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Monday, September 4, 2023

Yellowstone National Park

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Yellowstone_National_Park
Yellowstone National Park
Lower Yellowstone Falls
 
Location
Nearest townWest Yellowstone, Montana
Coordinates44°35′47″N 110°32′50″W
Area2,219,791 acres (8,983.18 km2)
Elevation8,104 ft (2,470 m)
EstablishedMarch 1, 1872; 151 years ago
Visitors3,290,242 (in 2022)
Governing bodyU.S. National Park Service
Websitewww.nps.gov/yell/

Yellowstone National Park is a national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowstone National Park Protection Act and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U.S. and is also widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features, especially the Old Faithful geyser, one of its most popular. While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.

While Native Americans have lived in the Yellowstone region for at least 11,000 years, aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park originally fell under the jurisdiction of the U.S. Department of the Interior, the first Secretary of the Interior to supervise the park being Columbus Delano. However, the U.S. Army was eventually commissioned to oversee the management of Yellowstone for 30 years between 1886 and 1916. In 1917, the administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites.

Yellowstone National Park spans an area of 3,468.4 sq mi (8,983 km2), comprising lakes, canyons, rivers, and mountain ranges. Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest super volcano on the continent. The caldera is considered a dormant volcano. It has erupted with tremendous force several times in the last two million years. Well over half of the world's geysers and hydrothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining nearly intact ecosystem in the Earth's northern temperate zone. In 1978, Yellowstone was named a UNESCO World Heritage Site.

Hundreds of species of mammals, birds, fish, reptiles, and amphibians have been documented, including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Yellowstone Park is the largest and most famous megafauna location in the contiguous United States. Grizzly bears, cougars, wolves, and free-ranging herds of bison and elk live in this park. The Yellowstone Park bison herd is the oldest and largest public bison herd in the United States. Forest fires occur in the park each year; in the large forest fires of 1988, nearly one-third of the park was burnt. Yellowstone has numerous recreational opportunities, including hiking, camping, boating, fishing, and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors often access the park by way of guided tours that use either snow coaches or snowmobiles.

History

The park contains the headwaters of the Yellowstone River, from which it takes its historical name. Near the end of the 18th century, French trappers named the river Roche Jaune, which is probably a translation of the Hidatsa name Mi tsi a-da-zi ("Yellow Stone River"). Later, American trappers rendered the French name in English as "Yellow Stone". Although it is commonly believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the Native American name source is unclear.

Detailed pictorial map from 1904

The human history of the park began at least 11,000 years ago when Native Americans began to hunt and fish in the region. During the construction of the post office in Gardiner, Montana, in the 1950s, an obsidian point of Clovis origin was found that dated from approximately 11,000 years ago. These Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian found in the park to make cutting tools and weapons. Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east. When the Lewis and Clark Expedition entered present-day Montana in 1805 they encountered the Nez Perce, Crow, and Shoshone tribes who described to them the Yellowstone region to the south, but they chose not to investigate.

In 1806, John Colter, a member of the Lewis and Clark Expedition, left to join a group of fur trappers. After splitting up with the other trappers in 1807, Colter passed through a portion of what later became the park, during the winter of 1807–1808. He observed at least one geothermal area in the northeastern section of the park, near Tower Fall. After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809, Colter described a place of "fire and brimstone" that most people dismissed as delirium; the supposedly mystical place was nicknamed "Colter's Hell". Over the next 40 years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers, and petrified trees, yet most of these reports were believed at the time to be a myth.

After an 1856 exploration, mountain man Jim Bridger (also believed to be the first or second European American to have seen the Great Salt Lake) reported observing boiling springs, spouting water, and a mountain of glass and yellow rock. These reports were largely ignored because Bridger was a known "spinner of yarns". In 1859, a U.S. Army Surveyor named Captain William F. Raynolds embarked on a two-year survey of the southern central Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party—which included geologist Ferdinand V. Hayden and guide Jim Bridger—attempted to cross the Continental Divide over Two Ocean Plateau from the Wind River drainage in northwest Wyoming. Heavy spring snows prevented their passage but had they been able to traverse the divide, the party would have been the first organized survey to enter the Yellowstone region. The American Civil War hampered further organized explorations until the late 1860s.

Ferdinand V. Hayden (1829–1887), an American geologist who convinced Congress to make Yellowstone a national park in 1872

The first detailed expedition to the Yellowstone area was the Cook–Folsom–Peterson Expedition of 1869, which consisted of three privately funded explorers. The Folsom party followed the Yellowstone River to Yellowstone Lake. The members of the Folsom party kept a journal and based on the information it reported, a party of Montana residents organized the Washburn–Langford–Doane Expedition in 1870. It was headed by the surveyor-general of Montana Henry Washburn, and included Nathaniel P. Langford (who later became known as "National Park" Langford) and a U.S. Army detachment commanded by Lt. Gustavus Doane. The expedition spent about a month exploring the region, collecting specimens, and naming sites of interest.

A Montana writer and lawyer named Cornelius Hedges, who had been a member of the Washburn expedition, proposed that the region should be set aside and protected as a national park; he wrote detailed articles about his observations for the Helena Herald newspaper between 1870 and 1871. Hedges essentially restated comments made in October 1865 by acting Montana Territorial Governor Thomas Francis Meagher, who had previously commented that the region should be protected. Others made similar suggestions. An 1871 letter to Ferdinand V. Hayden from Jay Cooke, a businessman who wanted to bring tourists to the region, encouraged him to mention it in his official report of the survey. Cooke wrote that his friend, Congressman William D. Kelley had also suggested "Congress pass a bill reserving the Great Geyser Basin as a public park forever".

Park creation

An old contour map showing mountainous terrain and a large lake
Ferdinand V. Hayden's map of Yellowstone National Park, 1871

In 1871, eleven years after his failed first effort, Ferdinand V. Hayden was finally able to explore the region. With government sponsorship, he returned to the region with a second, larger expedition, the Hayden Geological Survey of 1871. He compiled a comprehensive report, including large-format photographs by William Henry Jackson and paintings by Thomas Moran. The report helped to convince the U.S. Congress to withdraw this region from public auction. On March 1, 1872, President Ulysses S. Grant signed The Act of Dedication law that created Yellowstone National Park.

Hayden, while not the only person to have thought of creating a park in the region, was its first and most enthusiastic advocate. He believed in "setting aside the area as a pleasure ground for the benefit and enjoyment of the people" and warned that there were those who would come and "make merchandise of these beautiful specimens". Worrying the area could face the same fate as Niagara Falls, he concluded the site should "be as free as the air or Water". In his report to the Committee on Public Lands, he concluded that if the bill failed to become law, "the vandals who are now waiting to enter into this wonder-land, will in a single season despoil, beyond recovery, these remarkable curiosities, which have required all the cunning skill of nature thousands of years to prepare".

Hayden and his 1871 party recognized Yellowstone as a unique place that should be available for further research. He also was encouraged to preserve it for others to see and experience it as well. In 1873, Congress authorized and funded a survey to find a wagon route to the park from the south which was completed by the Jones Expedition of 1873. Eventually the railroads and, sometime after that, the automobile would make that possible. The park was not set aside strictly for ecological purposes; however, the designation "pleasure ground" was not an invitation to create an amusement park. Hayden imagined something akin to the scenic resorts and baths in England, Germany, and Switzerland.

THE ACT OF DEDICATION

AN ACT to set apart a certain tract of land lying near the headwaters of the Yellowstone River as a public park. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the tract of land in the Territories of Montana and Wyoming ... is hereby reserved and withdrawn from settlement, occupancy, or sale under the laws of the United States, and dedicated and set apart as a public park or pleasuring ground for the benefit and enjoyment of the people; and all persons who shall locate, or settle upon, or occupy the same or any part thereof, except as hereinafter provided, shall be considered trespassers and removed there from ...

Approved March 1, 1872.

Signed by:

A middle-aged man in formal attire with a beard
Portrait of Nathaniel P. Langford (1870), the first superintendent of the park

There was considerable local opposition to Yellowstone National Park during its early years. Some of the locals feared that the regional economy would be unable to thrive if there remained strict federal prohibitions against resource development or settlement within park boundaries and local entrepreneurs advocated reducing the size of the park so that mining, hunting, and logging activities could be developed. To this end, numerous bills were introduced into Congress by Montana representatives who sought to remove the federal land-use restrictions.

After the park's official formation, Nathaniel Langford was appointed as the park's first superintendent in 1872 by the Secretary of Interior Columbus Delano, the first overseer and controller of the park. Langford served for five years but was denied a salary, funding, and staff. Langford lacked the means to improve the land or properly protect the park, and without formal policy or regulations, he had few legal methods to enforce such protection. This left Yellowstone vulnerable to poachers, vandals, and others seeking to raid its resources. He addressed the practical problems park administrators faced in the 1872 Report to the Secretary of the Interior and correctly predicted that Yellowstone would become a major international attraction deserving the continuing stewardship of the government. In 1874, both Langford and Delano advocated the creation of a federal agency to protect the vast park, but Congress refused. In 1875, Colonel William Ludlow, who had previously explored areas of Montana under the command of George Armstrong Custer, was assigned to organize and lead an expedition to Montana and the newly established Yellowstone Park. Observations about the lawlessness and exploitation of park resources were included in Ludlow's Report of a Reconnaissance to the Yellowstone National Park. The report included letters and attachments by other expedition members, including naturalist and mineralogist George Bird Grinnell.

Great Falls of the Yellowstone, U.S. Geological and Geographic Survey of the Territories (1874–1879), photographer William Henry Jackson

Grinnell documented the poaching of buffalo, deer, elk, and antelope for hides: "It is estimated that during the winter of 1874–1875, not less than 3,000 buffalo and mule deer suffer even more severely than the elk, and the antelope nearly as much."

As a result, Langford was forced to step down in 1877. Having traveled through Yellowstone and witnessed land management problems, Philetus Norris volunteered for the position following Langford's exit. Congress finally saw fit to implement a salary for the position, as well as to provide minimal funding to operate the park. Norris used these funds to expand access to the park, building numerous crude roads and facilities.

In 1880, Harry Yount was appointed as a gamekeeper to control poaching and vandalism in the park. Yount had previously spent decades exploring the mountain country of present-day Wyoming, including the Grand Tetons, after joining F V. Hayden's Geological Survey in 1873. Yount is the first national park ranger, and Yount's Peak, at the head of the Yellowstone River, was named in his honor. However, these measures still proved to be insufficient in protecting the park, as neither Norris nor the three superintendents who followed, were given sufficient manpower or resources.

The Northern Pacific Railroad built a train station in Livingston, Montana as a gateway terminus to connect to the northern entrance area in 1883, which helped to increase visitation from 300 in 1872 to 5,000 in 1883. The spur line was completed in fall of that year from Livingston to Cinnabar for stage connection to Mammoth, then in 1902 extended to Gardiner station, where passengers also switched to stagecoach. Visitors in these early years faced poor and dusty roads plus limited services, with automobiles first admitted in phases beginning only in 1915. By 1901 a Chicago, Burlington & Quincy connection opened via Cody and in 1908 a Union Pacific Railroad connection to West Yellowstone, followed by a 1927 Milwaukee Road connection to Gallatin Gateway near Bozeman, also motorcoaching visitors via West Yellowstone. Rail visitation fell off considerably by World War II and ceased regular service in favor of the automobile around the 1960s, though special excursions occasionally continued into the early 1980s.

Top: Thomas Moran painted Tower Creek while on the Hayden Geological Survey of 1871. Bottom: Travertine Terrace, Mammoth Hot Springs

During the 1870s and 1880s, Native American tribes were effectively excluded from the national park. Under a half-dozen tribes had made seasonal use of the Yellowstone area- the only year-round residents were small bands of Eastern Shoshone known as "Sheepeaters". They left the area under the assurances of a treaty negotiated in 1868, under which the Sheepeaters ceded their lands but retained the right to hunt in Yellowstone. The United States never ratified the treaty and refused to recognize the claims of the Sheepeaters or any other tribe that had used Yellowstone.

The Nez Perce band associated with Chief Joseph, numbering about 750 people, passed through Yellowstone National Park in thirteen days in late August 1877. They were being pursued by the U.S. Army and entered the national park about two weeks after the Battle of the Big Hole. Some of the Nez Perce were friendly to the tourists and other people they encountered in the park; some were not. Nine park visitors were briefly taken captive. Despite Joseph and other chiefs ordering that no one should be harmed, at least two people were killed and several wounded. One of the areas where encounters occurred was in Lower Geyser Basin and east along a branch of the Firehole River to Mary Mountain and beyond. That stream is still known as Nez Perce Creek. A group of Bannocks entered the park in 1878, alarming park Superintendent Philetus Norris. In the aftermath of the Sheepeater Indian War of 1879, Norris built a fort to prevent Native Americans from entering the national park.

A group of buildings with trees and hills in background
Fort Yellowstone (circa 1910), formerly a U.S. Army post, now serves as park headquarters.

Ongoing poaching and destruction of natural resources continued unabated until the U.S. Army arrived at Mammoth Hot Springs in 1886 and built Camp Sheridan. Over the next 22 years, as the army constructed permanent structures, Camp Sheridan was renamed Fort Yellowstone. On May 7, 1894, the Boone and Crockett Club, acting through the personality of George G. Vest, Arnold Hague, William Hallett Phillips, W. A. Wadsworth, Archibald Rogers, Theodore Roosevelt, and George Bird Grinnell were successful in carrying through the Park Protection Act, which saved the park. The Lacey Act of 1900 provided legal support for the officials prosecuting poachers. With the funding and manpower necessary to keep a diligent watch, the army developed its own policies and regulations that permitted public access while protecting park wildlife and natural resources. When the National Park Service was created in 1916, many of the management principles developed by the army were adopted by the new agency. The army turned control over to the National Park Service on October 31, 1918.

In 1898, the naturalist John Muir described the park as follows:

However orderly your excursions or aimless, again and again amid the calmest, stillest scenery you will be brought to a standstill hushed and awe-stricken before phenomena wholly new to you. Boiling springs and huge deep pools of purest green and azure water, thousands of them, are plashing and heaving in these high, cool mountains as if a fierce furnace fire were burning beneath each one of them; and a hundred geysers, white torrents of boiling water and steam, like inverted waterfalls, are ever and anon rushing up out of the hot, black underworld.

Later history

Superintendent Horace M. Albright and black bears (1922). Tourists often fed black bears in the park's early years, with 527 injuries reported from 1931 to 1939.

By 1915, 1,000 automobiles per year were entering the park, resulting in conflicts with horses and horse-drawn transportation. Horse travel on roads was eventually prohibited.

The Civilian Conservation Corps (CCC), a New Deal relief agency for young men, played a major role between 1933 and 1942 in developing Yellowstone facilities. CCC projects included reforestation, campground development of many of the park's trails and campgrounds, trail construction, fire hazard reduction, and fire-fighting work. The CCC built the majority of the early visitor centers, campgrounds, and the current system of park roads.

During World War II, tourist travel fell sharply, staffing was cut, and many facilities fell into disrepair. By the 1950s, visitation increased tremendously in Yellowstone and other national parks. To accommodate the increased visitation, park officials implemented Mission 66, an effort to modernize and expand park service facilities. Planned to be completed by 1966, in honor of the 50th anniversary of the founding of the National Park Service, Mission 66 construction diverged from the traditional log cabin style with design features of a modern style. During the late 1980s, most construction styles in Yellowstone reverted to the more traditional designs. After the enormous forest fires of 1988 damaged much of Grant Village, structures there were rebuilt in the traditional style. The visitor center at Canyon Village, which opened in 2006, incorporates a more traditional design as well.

A large arch made of irregular-shaped natural stone over a road
The Roosevelt Arch in Gardiner, Montana, at the north entrance

The 1959 Hebgen Lake earthquake just west of Yellowstone at Hebgen Lake damaged roads and some structures in the park. In the northwest section of the park, new geysers were found, and many existing hot springs became turbid. It was the most powerful earthquake to hit the region in recorded history.

In 1963, after several years of public controversy regarding the forced reduction of the elk population in Yellowstone, the United States Secretary of the Interior Stewart Udall appointed an advisory board to collect scientific data to inform future wildlife management of the national parks. In a paper known as the Leopold Report, the committee observed that culling programs at other national parks had been ineffective, and recommended the management of Yellowstone's elk population.

The wildfires during the summer of 1988 were the largest in the history of the park. Approximately 793,880 acres (3,210 km2; 1,240 sq mi) or 36% of the parkland was impacted by the fires, leading to a systematic re-evaluation of fire management policies. The fire season of 1988 was considered normal until a combination of drought and heat by mid-July contributed to an extreme fire danger. On "Black Saturday", August 20, 1988, strong winds expanded the fires rapidly, and more than 150,000 acres (610 km2; 230 sq mi) burned.

Pictorial map by Heinrich C. Berann (1991); scale exaggerated

The expansive cultural history of the park has been documented by the 1,000 archeological sites that have been discovered. The park has 1,106 historic structures and features, and of these Obsidian Cliff and five buildings have been designated National Historic Landmarks. Yellowstone was designated an International Biosphere Reserve on October 26, 1976, and a UN World Heritage Site on September 8, 1978. The park was placed on the List of World Heritage in Danger from 1995 to 2003 due to the effects of tourism, infection of wildlife, and issues with invasive species. In 2010, Yellowstone National Park was honored with its own quarter under the America the Beautiful Quarters Program.

Justin Farrell explores three moral sensibilities that motivated activists in dealing with Yellowstone. First came the utilitarian vision of maximum exploitation of natural resources, a characteristic of developers in the late 19th century. Second was the spiritual vision of nature inspired by Romanticism and the transcendentalists in the mid-19th century. The twentieth century saw the biocentric moral vision that focuses on the health of the ecosystem as theorized by Aldo Leopold, which led to the expansion of federally protected areas and the surrounding ecosystems.

Heritage and Research Center

The Heritage and Research Center is located at Gardiner, Montana, near the north entrance to the park. The center is home to the Yellowstone National Park's museum collection, archives, research library, historian, archeology lab, and herbarium. The Yellowstone National Park Archives maintain collections of historical records of Yellowstone and the National Park Service. The collection includes the administrative records of Yellowstone, as well as resource management records, records from major projects, and donated manuscripts and personal papers. The archives are affiliated with the National Archives and Records Administration.

Geography

Official park map c. 2020 (click on map to enlarge)
Satellite image of Yellowstone National Park in 2020

Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming. Another three percent is within Montana, with the remaining one percent in Idaho. The park is 63 miles (101 km) north to south, and 54 miles (87 km) west to east by air. Yellowstone is 2,219,789 acres (8,983 km2; 3,468 sq mi) in area, larger than either of the states of Rhode Island or Delaware. Rivers and lakes cover five percent of the land area, with the largest water body being Yellowstone Lake at 87,040 acres (352 km2; 136 sq mi). Yellowstone Lake is up to 400 feet (120 m) deep and has 110 miles (180 km) of shoreline. At an elevation of 7,733 feet (2,357 m) above sea level, Yellowstone Lake is the largest high-elevation lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland.

The Continental Divide of North America runs diagonally through the southwestern part of the park. The divide is a topographic feature that separates the Pacific Ocean and Atlantic Ocean water drainages. About one-third of the park lies on the west side of the divide. The origins of the Yellowstone and Snake Rivers are near each other but on opposite sides of the divide. As a result, the waters of the Snake River flow to the Pacific Ocean, while those of the Yellowstone find their way to the Gulf of Mexico.

The park sits on the Yellowstone Plateau, at an average elevation of 8,000 feet (2,400 m) above sea level. The plateau is bounded on nearly all sides by mountain ranges of the Middle Rocky Mountains, which range from 9,000 to 11,000 feet (2,700 to 3,400 m) in elevation. The highest point in the park is atop Eagle Peak (11,358 feet or 3,462 metres) and the lowest is along Reese Creek (5,282 feet or 1,610 metres). Nearby mountain ranges include the Gallatin Range to the northwest, the Beartooth Mountains in the north, the Absaroka Range to the east, the Teton Range to the south, and the Madison Range to the west. The most prominent summit on the Yellowstone Plateau is Mount Washburn at 10,243 feet (3,122 m).

Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least 15 feet (4.6 m), the highest being the Lower Falls of the Yellowstone River at 308 feet (94 m).

Three deep canyons are located in the park, cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640,000 years. The Lewis River flows through Lewis Canyon in the south, and the Yellowstone River has carved two colorful canyons, the Grand Canyon of the Yellowstone and the Black Canyon of the Yellowstone in its journey north.

Geology

Volcanism

Columnar basalt near Tower Fall; large floods of basalt and other lava types preceded mega-eruptions of superheated ash and pumice.
Caldera rim on the horizon south of Yellowstone Lake.

Yellowstone is at the northeastern end of the Snake River Plain, a great bow-shaped arc through the mountains that extends roughly 400 miles (640 km) from the park to the Idaho-Oregon border.

The volcanism of Yellowstone is believed to be linked to the somewhat older volcanism of the Snake River Plain. Yellowstone is thus the active part of a hotspot that has moved northeast over time. The origin of this hotspot volcanism is disputed. One theory holds that a mantle plume has caused the Yellowstone hotspot to migrate northeast, while another theory explains migrating hotspot volcanism as the result of the fragmentation and dynamics of the subducted Farallon Plate in Earth's interior.

The Yellowstone Caldera is the largest volcanic system in North America, and worldwide it is only rivaled by the Lake Toba Caldera on Sumatra. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The magma chamber that lies under Yellowstone is estimated to be a single connected chamber, about 37 miles (60 km) long, 18 miles (29 km) wide, and 3 to 7 miles (4.8 to 11.3 km) deep. The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released more than 240 cu mi (1,000 km3) of ash, rock and pyroclastic materials. This eruption was more than 1,000 times larger than the 1980 eruption of Mount St. Helens. It produced a caldera nearly ⁵⁄₈ of a mile (1 km) deep and 45 by 28 miles (72 by 45 km) in area and deposited the Lava Creek Tuff, a welded tuff geologic formation. The most violent known eruption, which occurred 2.1 million years ago, ejected 588 cu mi (2,450 km3) of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff and the Island Park Caldera. A smaller eruption ejected 67 cu mi (280 km3) of material 1.3 million years ago, forming the Henry's Fork Caldera and depositing the Mesa Falls Tuff.

Each of the three climactic eruptions released vast amounts of ash that blanketed much of central North America, falling many hundreds of miles away. The amount of ash and gases released into the atmosphere probably caused significant impacts on world weather patterns and led to the extinction of some species, primarily in North America.

Boardwalks allow visitors to safely approach the thermal features, such as Grand Prismatic Spring.

A subsequent caldera-forming eruption occurred about 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Since the last supereruption, a series of smaller eruptive cycles between 640,000 and 70,000 years ago, has nearly filled in the Yellowstone Caldera with 80 different eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation.

Each eruption is part of an eruptive cycle that climaxes with the partial collapse of the roof of the volcano's partially emptied magma chamber. This creates a collapsed depression, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 800,000 years, but the small number of such climactic eruptions cannot be used to make an accurate prediction for future volcanic events.

Geysers and the hydrothermal system

Old Faithful erupts approximately every 90 minutes.
 
Steamboat Geyser is the world's largest active geyser.

The most famous geyser in the park, and perhaps the world, is Old Faithful geyser, located in Upper Geyser Basin. Castle Geyser, Lion Geyser, Beehive Geyser, Grand Geyser (the world's tallest predictable geyser), Giant Geyser (the world's most voluminous geyser), Riverside Geyser and numerous other geysers are in the same basin. The park contains the tallest active geyser in the world—Steamboat Geyser in the Norris Geyser Basin. A study that was completed in 2011 found that at least 1,283 geysers have erupted in Yellowstone. Of these, an average of 465 are active in a given year. Yellowstone contains at least 10,000 geothermal features altogether, including geysers, hot springs, mudpots, and fumaroles. Over half of the world's geysers and hydrothermal features are concentrated in Yellowstone.

In May 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah created the Yellowstone Volcano Observatory (YVO), a partnership for long-term monitoring of the geological processes of the Yellowstone Plateau volcanic field, for disseminating information concerning the potential hazards of this geologically active region.

In 2003, changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin. New fumaroles were observed, and several geysers showed enhanced activity and increasing water temperatures. Several geysers became so hot that they were transformed into purely steaming features; the water had become superheated and they could no longer erupt normally. This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past. Research indicated that these uplifts posed no immediate threat of a volcanic eruption, since they may have developed long ago, and there had been no temperature increase found near the uplifts.

On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion. This was closely followed by an upsurge in earthquake activity in April 2004. In 2006, it was reported that the Mallard Lake Dome and the Sour Creek Dome—areas that have long been known to show significant changes in their ground movement—had risen at a rate of 1.5 to 2.4 inches (3.8 to 6.1 cm) per year from mid–2004 through 2006. As of late 2007, the uplift has continued at a reduced rate. These events inspired a great deal of media attention and speculation about the geologic future of the region. Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future. However, these changes demonstrate the dynamic nature of the Yellowstone hydrothermal system.

Earthquakes

Infrastructure damage at Hebgen Lake due to the 7.2 magnitude earthquake of 1959

Yellowstone experiences thousands of small earthquakes every year, virtually all of which are undetectable to people. There have been six earthquakes with at least magnitude 6 or greater in historical times, including the 7.2‑magnitude Hebgen Lake earthquake which occurred just outside the northwest boundary of the park in 1959. This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake; immediately downstream, the sediment from the landslide dammed the river and created a new lake, known as Earthquake Lake. Twenty-eight people were killed, and property damage was extensive in the immediate region. The earthquake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs that normally have clear water turned muddy. A 6.1‑magnitude earthquake struck inside the park on June 30, 1975, but the damage was minimal.

For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera. Beginning on April 30, 2007, 16 small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008. In December 2008, over 250 earthquakes were measured over four days under Yellowstone Lake, the largest measuring a magnitude of 3.9. In January 2010, more than 250 earthquakes were detected over two days. Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey.

On March 30, 2014, a magnitude 4.8 earthquake struck almost the very middle of Yellowstone near the Norris Basin at 6:34 am; reports indicated no damage. This was the largest earthquake to hit the park since February 22, 1980.

Biology and ecology

Meadow in Yellowstone National Park

Yellowstone National Park is the centerpiece of the 20 million acres (80,940 km2; 31,250 sq mi) Greater Yellowstone Ecosystem, a region that includes Grand Teton National Park, adjacent National Forests and expansive wilderness areas in those forests. The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the contiguous United States, considered the world's largest intact ecosystem in the northern temperate zone. With the successful wolf reintroduction program, which began in the 1990s, much the original faunal and floral species known to inhabit the region when the first explorers entered the area can be found there.

Flora

Over 69000 species of trees and other vascular plants are native to the park. Another 170 species are considered to be exotic species and are non-native. Of the eight conifer tree species documented, Lodgepole Pine forests cover 80% of the total forested areas. Other conifers, such as Subalpine Fir, Engelmann Spruce, Rocky Mountain Douglas-fir and Whitebark Pine, are found in scattered groves throughout the park. As of 2007, the whitebark pine is threatened by a fungus known as white pine blister rust; however, this is mostly confined to forests well to the north and west. In Yellowstone, about seven percent of the whitebark pine species have been impacted with the fungus, compared to nearly complete infestations in northwestern Montana. Quaking Aspen and willows are the most common species of deciduous trees. The aspen forests have declined significantly since the early 20th century, but scientists at Oregon State University attribute the recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk.

Yellowstone sand verbena are endemic to Yellowstone's lakeshores.

There are dozens of species of flowering plants that have been identified, most of which bloom between May and September. The Yellowstone sand verbena is a rare flowering plant found only in Yellowstone. It is closely related to species usually found in much warmer climates, making the sand verbena an enigma. The estimated 8,000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake, well above the waterline.

Microbial mat in cooled geyser water, Upper Geyser Basin.

In Yellowstone's hot waters, bacteria form mats of bizarre shapes consisting of trillions of individuals. These bacteria are some of the most primitive life forms on earth. Flies and other arthropods live on the mats, even in the middle of the bitterly cold winters. Initially, scientists thought that microbes there gained sustenance only from sulfur. In 2005 researchers from the University of Colorado at Boulder discovered that the sustenance for at least some of the diverse hyperthermophilic species is molecular hydrogen.

Thermus aquaticus is a bacterium found in the Yellowstone hot springs that produces an important enzyme (Taq polymerase) that is easily replicated in the lab and is useful in replicating DNA as part of the polymerase chain reaction (PCR) process. The retrieval of these bacteria can be achieved with no impact on the ecosystem. Other bacteria in the Yellowstone hot springs may also prove useful to scientists who are searching for cures for various diseases. In 2016, researchers from Uppsala University reported the discovery of a class of thermophiles, Hadesarchaea, in Yellowstone's Culex Basin. These organisms are capable of converting carbon monoxide and water to carbon dioxide and hydrogen.

Non-native plants sometimes threaten native species by occupying nutrient resources. Though exotic species are most commonly found in areas with the greatest human visitation, such as near roads and at major tourist areas, they have also spread into the backcountry. Generally, most exotic species are controlled by pulling the plants out of the soil or by spraying, both of which are time-consuming and expensive.

Fauna

Yellowstone is widely considered to be the finest megafauna wildlife habitat in the lower 48 states. There are almost 60 species of mammals in the park, including the Rocky Mountain wolf, coyote, the Canadian lynx, cougars, and black and grizzly bears. Other large mammals include the bison (often referred to as buffalo), elk, moose, mule deer, white-tailed deer, mountain goat, pronghorn, and bighorn sheep.

American bison

The Yellowstone Park bison herd is the largest public herd of American bison in the United States. Bison once numbered between 30 and 60 million individuals throughout North America, and Yellowstone remains one of their last strongholds. Their populations had increased from less than 50 in the park in 1902 to 4,000 by 2003. The Yellowstone Park bison herd reached a peak in 2005 with 4,900 animals. Despite a summer estimated population of 4,700 in 2007, the number dropped to 3,000 in 2008 after a harsh winter and controversial brucellosis management strategies which sent hundreds to slaughter.

Elk mother nursing her calf

The Yellowstone Park bison herd is believed to be one of only four free-roaming and genetically pure herds on public lands in North America. The other three herds are the Henry Mountains bison herd of Utah, at Wind Cave National Park in South Dakota, and in Elk Island National Park in Alberta.

The relatively large bison populations are a concern for ranchers, who fear that the species can transmit bovine diseases to their domesticated cousins. About half of Yellowstone's bison have been exposed to brucellosis, a bacterial disease that came to North America with European cattle that may cause cattle to miscarry. The disease has little effect on park bison, and no reported cases of transmission from wild bison to domestic livestock have been filed. However, the Animal and Plant Health Inspection Service (APHIS) has stated that bison are the "likely source" of the spread of the disease in cattle in Wyoming and North Dakota. Elk also carry the disease and are believed to have transmitted the infection to horses and cattle.

To combat the perceived threat of brucellosis transmission to cattle, national park personnel regularly corral bison herds back into the park when they venture outside of the area's borders. During the winter of 1996–1997, the bison herd was so large that 1,079 bison that had exited the park were either shot or sent to slaughter. Animal rights activists argue that this is a cruel practice and that the possibility for disease transmission is not as great as some ranchers maintain. Ecologists point out that the bison are merely traveling to seasonal grazing areas that lie within the Greater Yellowstone Ecosystem that have been converted to cattle grazing, some of which are within National Forests and are leased to private ranchers. APHIS has stated that with vaccinations and other means, brucellosis can be eliminated from the bison and elk herds throughout Yellowstone.

A reintroduced wolf in Yellowstone National Park

Starting in 1914, to protect elk populations, the U.S. Congress appropriated funds to be used for "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves. Gradually, wolves were virtually eliminated from Yellowstone. Further exterminations continued until the National Park Service ended the practice in 1935. With the passing of the Endangered Species Act in 1973, the wolf was one of the first mammal species listed. After the wolves were extirpated from Yellowstone, the coyote then became the park's top canine predator. Since the coyote is not able to bring down large animals, this lack of an apex predator resulted in a marked increase in lame and sick megafauna.

By the 1990s, the Federal government had reversed its views on wolves. In a controversial decision by the U.S. Fish and Wildlife Service (which oversees threatened and endangered species), northwestern wolves imported from Canada were reintroduced into the park. Reintroduction efforts have been successful, with populations remaining relatively stable. A survey conducted in 2005 reported that there were 13 wolf packs, totaling 118 individuals in Yellowstone and 326 in the entire ecosystem. These park figures were lower than those reported in 2004, but may be attributable to wolf migration to other nearby areas as suggested by the substantial increase in the Montana population during that interval. Almost all the wolves documented were descended from the 66 wolves reintroduced in 1995–96. The recovery of populations throughout the states of Wyoming, Montana, and Idaho has been so successful that on February 27, 2008, the U.S. Fish and Wildlife Service removed the Northern Rocky Mountain wolf population from the endangered species list.

Black bear and cub near Tower Fall

Black bears are common in the park and were a park symbol due to visitor interaction with the bears starting in 1910. Feeding and close contact with bears has not been permitted since the 1960s to reduce their desire for human foods. Yellowstone is one of the few places in the United States where black bears can be seen coexisting with grizzly bears. Black bear observations occur most often in the park's northern ranges, and in the Bechler area which is in the park's southwestern corner.

As of 2017, an estimated 700 grizzly bears were living in the Greater Yellowstone Ecosystem, with about 150 grizzlies living wholly or partially within Yellowstone National Park. The grizzly was initially listed as a threatened species in the contiguous United States on July 28, 1975, by the Fish and Wildlife Service. The grizzly bear was taken off the endangered species list in 2007. Opponents of delisting the grizzly expressed concerns that states might once again allow hunting and that better conservation measures were needed to ensure a sustainable population. A federal district judge overturned the delisting ruling in 2009, reinstating the grizzly; however, the grizzly was once again removed from the list in 2017. In September 2018, a U.S. district judge ruled that the grizzly's protections must be restored in full, arguing the Fish and Wildlife Service was mistaken in removing the bear from the threatened status list. Regardless of the rulings, hunting is prohibited within Yellowstone National Park. Hunters who legally hunt animals outside park boundaries may transport the carcass through the park with a permit.

Elk in Hayden Valley

Population figures for elk are more than 30,000—the largest population of any large mammal species in Yellowstone. The northern herd has decreased enormously since the mid‑1990s; this has been attributed to wolf predation and causal effects such as elk using more forested regions to evade predation, consequently making it harder for researchers to accurately count them. The northern herd migrates west into southwestern Montana in the winter. The southern herd migrates southward, and the majority of this elk winter on the National Elk Refuge, immediately southeast of Grand Teton National Park. The southern herd migration is the largest mammalian migration remaining in the U.S. outside of Alaska.

In 2003 the tracks of one female lynx and her cub were spotted and followed for over 2 miles (3.2 km). Fecal material and other evidence obtained were tested and confirmed to be those of a lynx. No visual confirmation was made, however. Lynx have not been seen in Yellowstone since 1998, though DNA taken from hair samples obtained in 2001 confirmed that lynx were at least transient to the park. Other less commonly seen mammals include the mountain lion and wolverine. The mountain lion has an estimated population of only 25 individuals parkwide. Accurate population figures for the wolverine are not known. These uncommon and rare mammals provide insight into the health of protected lands such as Yellowstone and help managers make determinations as to how best to preserve habitats.

Pronghorn are commonly found on the grasslands in the park.

Eighteen species of fish live in Yellowstone, including the core range of the Yellowstone cutthroat trout—a fish highly sought by anglers. The Yellowstone cutthroat trout has faced several threats since the 1980s, including the suspected illegal introduction into Yellowstone Lake of lake trout, an invasive species which consume the smaller cutthroat trout. Although lake trout were established in Shoshone and Lewis lakes (on the Snake River drainage) after U.S. government stocking operations in 1890, it was never officially introduced into the Yellowstone River drainage. The cutthroat trout has also faced an ongoing drought, as well as the accidental introduction of a parasite—whirling disease—which causes a terminal nervous system disease in younger fish. Since 2001, all native sport fish species caught in Yellowstone waterways are subject to catch and release regulations.

Yellowstone is also home to seven species of reptiles, including the painted turtle, Rubber boa, and prairie rattlesnake, bullsnake, sagebrush lizard, valley garter snake and wandering garter snake and four species of amphibians, including the boreal chorus frog, tiger salamander, western toad and columbia spotted frog.

Three hundred eleven species of birds have been reported, almost half of which nest in Yellowstone. In 1999, twenty-six pairs of nesting bald eagle were documented. Extremely rare sightings of whooping cranes have been recorded, however, only three examples of this species are known to live in the Rocky Mountains, out of 385 known worldwide. Other birds, considered to be species of special concern because of their rarity in Yellowstone, include the common loon, harlequin duck, osprey, peregrine falcon and the trumpeter swan.

Forest fires

Fire in Yellowstone National Park

As wildfire is a natural part of most ecosystems, plants that are indigenous to Yellowstone have adapted in a variety of ways. Douglas-fir have a thick bark that protects the inner section of the tree from most fires. Lodgepole Pines—the most common tree species in the park—generally have cones that are only opened by the heat of a fire. Their seeds are held in place by a tough resin, and fire assists in melting the resin, allowing the seeds to disperse. Fire clears out dead and downed wood, providing fewer obstacles for lodgepole pines to flourish. Subalpine Fir, Engelmann Spruce, Whitebark Pine, and other species tend to grow in colder and moister areas, where the fire is less likely to occur. Aspen trees sprout new growth from their roots, and even if a severe fire kills the tree above ground, the roots often survive unharmed because they are insulated from the heat by soil. The National Park Service estimates that in natural conditions, grasslands in Yellowstone burned an average of every 20 to 25 years, while forests in the park would experience fire about every 300 years.

About thirty-five natural forest fires are ignited each year by lightning, while another six to ten are started by people—in most cases by accident. Yellowstone National Park has three fire lookout towers, each staffed by trained firefighters. The easiest one to reach is atop Mount Washburn, which has interpretive exhibits and an observation deck open to the public. The park also monitors fire from the air and relies on visitor reports of smoke and/or flames. Fire towers are staffed almost continuously from late June to mid-September—the primary fire season. Fires burn with the greatest intensity in the late afternoon and evening. Few fires burn more than 100 acres (40 ha), and the vast majority of fires reach only a little over an acre (0.5 ha) before they burn themselves out. Fire management focuses on monitoring dead and down wood quantities, soil, and tree moisture, and the weather, to determine those areas most vulnerable to fire should one ignite. The current policy is to suppress all human-caused fires and to evaluate natural fires, examining the benefit or detriment they may pose to the ecosystem. If a fire is considered to be an immediate threat to people and structures, or will burn out of control, then fire suppression is performed.

Wildfire in Yellowstone National Park produces a pyrocumulus cloud.

To minimize the chances of out-of-control fires and threats to people and structures, park employees do more than just monitor the potential for fire. Controlled burns are prescribed fires that are deliberately started to remove dead timber under conditions that allow firefighters an opportunity to carefully control where and how much wood is consumed. Natural fires are sometimes considered prescribed fires if they are left to burn. In Yellowstone, unlike some other parks, there have been very few fires deliberately started by employees as prescribed burns. However, over the last 30 years, over 300 natural fires have been allowed to burn naturally. In addition, firefighters remove dead and down wood and other hazards from areas where they will be a potential fire threat to lives and property, reducing the chances of fire danger in these areas. Fire monitors also regulate fire through educational services to the public and have been known to temporarily ban campfires from campgrounds during periods of high fire danger. The common notion in early United States land management policies was that all forest fires were bad. The fire was seen as a purely destructive force and there was little understanding that it was an integral part of the ecosystem. Consequently, until the 1970s, when a better understanding of wildfire was developed, all fires were suppressed. This led to an increase in dead and dying forests, which would later provide the fuel load for fires that would be much harder, and in some cases, impossible to control. The latest Fire Management Plan (2014) allows natural fires to burn if they posed no immediate threat to lives and property.

A crown fire approaches the Old Faithful complex on September 7, 1988.

The spring season of 1988 was wet, but by summer, drought began moving in throughout the northern Rockies, creating the driest year on record to that point. Grasses and plants which grew well in the early summer from the abundant spring moisture produced plenty of grass, which soon turned to dry tinder. The National Park Service began firefighting efforts to keep the fires under control, but the extreme drought made suppression difficult. Between July 15 and 21, 1988, fires quickly spread from 8,500 acres (3,400 ha; 13.3 sq mi) throughout the entire Yellowstone region, which included areas outside the park, to 99,000 acres (40,000 ha; 155 sq mi) on the park land alone. By the end of the month, the fires were out of control. Large fires burned together, and on August 20, 1988, the single worst day of the fires, more than 150,000 acres (61,000 ha; 230 sq mi) were consumed. Seven large fires were responsible for 95% of the 793,000 acres (321,000 ha; 1,239 sq mi) that were burned over the next couple of months. The cost of 25,000 firefighters and U.S. military forces participating in the suppression efforts was 120 million dollars. By the time winter brought snow that helped extinguish the last flames, the fires had destroyed 67 structures and caused several million dollars in damage. Though no civilians died, two personnel associated with the firefighting efforts were killed.

Contrary to media reports and speculation at the time, the fires killed very few park animals—surveys indicated that only about 345 elk (of an estimated 40,000–50,000), 36 deer, 12 moose, 6 black bears, and 9 bison had perished. Changes in fire management policies were implemented by land management agencies throughout the United States, based on knowledge gained from the 1988 fires and the evaluation of scientists and experts from various fields. By 1992, Yellowstone had adopted a new fire management plan which observed stricter guidelines for the management of natural fires.

Climate and weather

Winter scene in Yellowstone
Geyser at Yellowstone Lake

Yellowstone's climate is greatly influenced by altitude, with lower elevations generally found to be warmer year-round. The record high temperature was 99 °F (37 °C) in 2002, while the coldest temperature recorded is −66 °F (−54 °C) in 1933. During the summer months of June to early September, daytime highs are normally in the 70 to 80 °F (21 to 27 °C) range, while nighttime lows can go to below freezing (0 °C), especially at higher altitudes. Summer afternoons are frequently accompanied by thunderstorms. Spring and fall temperatures range between 30 and 60 °F (−1 and 16 °C) with nights in the teens to single digits (−5 to −20 °C). Winter in Yellowstone is accompanied by high temperatures usually between zero and twenty °F (−18 and −7 °C) and nighttime temperatures below zero °F (−18 °C) for most of the winter.

Precipitation in Yellowstone is highly variable and ranges from 15 inches (380 mm) annually near Mammoth Hot Springs, to 80 inches (2,000 mm) in the southwestern sections of the park. The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain to the west that was, in turn, formed by Yellowstone itself. Snow is possible in any month of the year, but most common between November and April, with averages of 150 inches (3,800 mm) annually around Yellowstone Lake, to twice that amount at higher elevations.

The climate at Yellowstone Lake is classified as subarctic (Dfc), according to Köppen-Geiger climate classification, while at the park headquarters, the classification is humid continental (Dfb).

Tornadoes in Yellowstone are rare; however, on July 21, 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness of Bridger-Teton National Forest and hit Yellowstone National Park. Called the Teton–Yellowstone tornado, it was classified as an F4, with wind speeds estimated at between 207 and 260 miles per hour (333 and 418 km/h). The tornado left a path of destruction 1 to 2 miles (1.6 to 3.2 km) wide, and 24 miles (39 km) long, and leveled 15,000 acres (6,100 ha; 23 sq mi) of mature pine forest.

In June 2022, the park closed entrances and evacuated visitors after experiencing record-level rainfall and flooding that caused multiple road and bridge failures, power outages, and mudslides. A combination of heavy rain and rapid snow melt resulted in the Yellowstone River rising to a new record height at 13.88 feet (4.23 m), breaking a previous record of 11.5 feet (3.5 m) set in 1918. Flooding on the Lamar River reached 16.7 feet (5.1 m), beating a 1996 record of 12.15 feet (3.70 m). Damage from the flooding includes washed out roads and bridges, and damage to infrastructure systems including electricity, water and wastewater systems. It was initially forecasted that the park would not be able to reopen the north entrance by Gardiner, MT, or the northeast entrance near Cooke City, MT, during the 2022 season. The park partially reopened Wednesday, June 22, after a 9-day closure. The north entrance was opened on October 30, two days ahead of schedule. The northeast entrance was opened on October 15. To limit the nearly one million visitors per month that visit in the summer, the park temporarily restricted entry to cars based on license plates. 

Recreation

Union Pacific Railroad brochure promoting travel to the park (1921)

Yellowstone ranks among the most popular national parks in the United States. Since the mid-1960s, at least 2 million tourists have visited the park almost every year. Average annual visitation increased to 3.5 million during the ten years from 2007 to 2016, with a record of 4,257,177 recreational visitors in 2016. July is the busiest month for Yellowstone National Park. At peak summer levels, 3,700 employees work for Yellowstone National Park concessionaires. Concessionaires manage nine hotels and lodges, with a total of 2,238 hotel rooms and cabins available. They also oversee gas stations, stores, and most of the campgrounds. Another 800 employees work either permanently or seasonally for the National Park Service.

Tourists watch Old Faithful erupt, 2019.

Park service roads lead to major features; however, road reconstruction has produced temporary road closures. Yellowstone is in the midst of a long-term road reconstruction effort, which is hampered by a short repair season. In the winter, all roads aside from the one which enters from Gardiner, Montana, and extends to Cooke City, Montana, are closed to wheeled vehicles. Park roads are closed to wheeled vehicles from early November to mid-April, but some park roads remain closed until mid-May. The park has 310 miles (500 km) of paved roads which can be accessed from five different entrances. There is no public transportation available inside the park, but several tour companies can be contacted for guided (including self-guided) motorized transport. In the winter, concessionaires operate guided snowmobile and snow coach tours, though their numbers and access are based on quotas established by the National Park Service. Facilities in the Old Faithful, Canyon and Mammoth Hot Springs areas of the park are very busy during the summer months. Traffic jams created by road construction or by people observing wildlife can result in long delays.

The National Park Service maintains nine visitor centers and museums and is responsible for the maintenance of historical structures and many of the other 2,000 buildings. These structures include National Historical Landmarks such as the Old Faithful Inn built from 1903 to 1904 and the entire Fort Yellowstone – Mammoth Hot Springs Historic District. A historical and educational tour is available at Fort Yellowstone which details the history of the National Park Service and the development of the park. Campfire programs, guided walks, and other interpretive presentations normally available at numerous locations in the summer, and on a limited basis during other seasons were suspended in 2021 as a response to COVID-19.

Camping is available at a dozen campgrounds with more than 2,000 campsites. Camping is also available in surrounding National Forests, as well as in Grand Teton National Park to the south. Backcountry campsites are accessible only by foot or by horseback and require a permit. There are 1,100 miles (1,800 km) of hiking trails available. The park is not considered to be a good destination for mountaineering because of the instability of volcanic rock which predominates. Visitors with pets are required to keep them on a leash at all times and are limited to areas near roadways and in "front country" zones such as drive-in campgrounds. Around thermal features, wooden and paved trails have been constructed to ensure visitor safety, and most of these areas are handicapped accessible. The National Park Service maintains a year-round clinic at Mammoth Hot Springs and provides emergency services throughout the year.

Hunting is not permitted, though it is allowed in the surrounding national forests during the open season. Fishing is a popular activity, and a Yellowstone Park fishing license is required to fish in park waters. Many park waters are fly fishing only and all native fish species are catch and release only. Boating is prohibited on rivers and creeks except for a 5 miles (8.0 km) stretch of the Lewis River between Lewis and Shoshone lakes, and it is open to non-motorized use only. Yellowstone Lake has a marina at Bridge Bay while there is a boat ramp at the Lewis lake campground.

Vintage photo of human-habituated bears seeking food from visitors

In the early history of the park, visitors were allowed, and sometimes even encouraged, to feed the bears. Visitors welcomed the chance to get their pictures taken with the bears, who had learned to beg for food. This led to numerous injuries to humans each year. In 1970, park officials changed their policy and started a vigorous program to educate the public on the dangers of close contact with bears, and to try to eliminate opportunities for bears to find food in campgrounds and trash collection areas. Although it has become more difficult to observe bears in recent years, the number of human injuries and deaths has taken a significant drop and visitors are in less danger. The eighth recorded bear-related death in the park's history occurred in August 2015.

Other protected lands in the region include Caribou-Targhee, Gallatin, Custer, Shoshone and Bridger-Teton National Forests. The National Park Service's John D. Rockefeller, Jr. Memorial Parkway is to the south and leads to Grand Teton National Park. The famed Beartooth Highway provides access from the northeast and has spectacular high-altitude scenery. Nearby communities include West Yellowstone, Montana; Cody, Wyoming; Red Lodge, Montana; Ashton, Idaho; and Gardiner, Montana. The closest air transport is available by way of Bozeman, Montana; Billings, Montana; Jackson; Cody, Wyoming, or Idaho Falls, Idaho. Salt Lake City, 320 miles (510 km) to the south, is the closest large metropolitan area.

Legal jurisdiction

Idaho portion of park highlighted in southwest corner (click to enlarge)

The entire park is within the jurisdiction of the United States District Court for the District of Wyoming, making it the only federal court district that includes portions of more than one state (Idaho, Montana, and Wyoming). Law professor Brian C. Kalt has argued that it may be impossible to impanel a jury in compliance with the Vicinage Clause of the Sixth Amendment for a crime committed solely in the unpopulated Idaho portion of the park (and that it would be difficult to do so for a crime committed solely in the lightly populated Montana portion). One defendant, who was accused of a wildlife-related crime in the Montana portion of the park, attempted to raise this argument but eventually pleaded guilty, with the plea deal including his specific agreement not to raise the issue in his appeal.

Sunday, September 3, 2023

Clovis culture

From Wikipedia, the free encyclopedia
 
Clovis
Map showing the extent of the Clovis culture
Geographical rangeNorth America
PeriodLithic
Datesc. 11,500 – 10,800 BCE
Type siteBlackwater Draw
Preceded byPaleo-Indians
Followed byFolsom tradition
"A Clovis blade with medium to large lanceolate spear-knife points. Side is parallel to convex and exhibit careful pressure flaking along the blade edge. The broadest area is near the midsection or toward the base. The base is distinctly concave with a characteristic flute or channel flake removed from one or, more commonly, both surfaces of the blade. The lower edges of the blade and base is ground to dull edges for hafting. Clovis points also tend to be thicker than the typically thin later stage Folsom points. Length: 4–20 cm/1.5–8 in. Width: 2.5–5 cm/1–2
A Clovis point created using bifacial percussion flaking, (which flakes both edges with a percussor). The deep flake initiated from the base constitutes the "flute" characteristic of Clovis and some other early Paleoindian points.

Clovis culture is a prehistoric Paleoamerican archaeological culture, named for distinct stone and bone tools found in close association with Pleistocene fauna, particularly two Columbian mammoths, at Blackwater Locality No. 1 near Clovis, New Mexico, in 1936 and 1937, though Paleoindian artifacts had been found at the site since the 1920s. It existed from roughly 11,500 to 10,800 BCE (≈13,500-12,800 years Before Present) near the end of the Last Glacial Period.

Clovis culture is characterized by the manufacture of "Clovis points" and distinctive bone and ivory tools, and it is represented by hundreds of sites, from which over 10,000 Clovis points have been recovered. Knowledge of the Clovis culture has primarily been gathered from North America. In South America, the similar related Fishtail or Fell projectile point style was contemporaneous to the usage of Clovis points in North America, and possibly developed from Clovis points.

The only human burial that has been directly associated with tools from the Clovis culture included the remains of an infant boy found in Montana that researchers named Anzick-1. Paleogenetic analyses of Anzick-1's ancient nuclear, mitochondrial, and Y-chromosome DNA reveal that Anzick-1 is closely related to some modern Native American populations, including those in Southern North America, Central America, and South America and populations in Central Asia and Siberia, which lends support to the Beringia or coastal Pacific hypotheses that they were responsible for the initial settlement of the Americas.

The Clovis culture is traditionally considered to have been based on highly mobile hunter-gatherer populations that heavily engaged in big game hunting, though some recent scholarship has questioned how reliant Clovis hunters were on big game. Recent experimental research casts doubt on whether Clovis points were well-suited for hunting mammoth at all, and suggests they were more often used as knives; however, a counterargument supports the traditional interpretation of points as effective hunting weapons used on large game, including mammoth and other proboscideans. 

The Clovis culture was replaced by several more localized regional societies from the Younger Dryas cold-climate period onward. Post-Clovis cultures include the Folsom tradition, Gainey, Suwannee, Simpson, Plainview-Goshen, Cumberland, and Redstone. Each of these is thought to derive directly from Clovis, in some cases apparently differing only in the length of the fluting on their projectile points. Although this is generally held to be the result of normal cultural change through time, numerous other reasons have been suggested as driving forces to explain changes in the archaeological record, such as the Younger Dryas postglacial climate change, and the decline and extinction of North American megafauna as part of the Quaternary extinction event. The potential causal role of Clovis hunters in the extinction of the megafauna has been the subject of controversy.

After the discovery of several Clovis sites in western North America in the 1930s (such as Blackwater Draw, NM and Dent, CO), the Clovis people came to be regarded as the first human inhabitants who created a widespread culture in the Americas and the ancestors of most of the indigenous peoples of the Americas.

Several archaeological discoveries have cast significant doubt on the Clovis-first theory, including sites discovered in present-day Cactus Hill near Richmond, Virginia, Paisley Caves in Paisley, Oregon, the Topper site in Allendale County, South Carolina, Meadowcroft Rockshelter in Jefferson Township, Pennsylvania, the Buttermilk Creek complex site near Salado, Texas, Cueva Fell and Monte Verde in Chile, and the White Sands site near Alamogordo, New Mexico.

The oldest claimed human archaeological site in the Americas is the Pedra Furada hearths in Brazil, controversially dated to 19,000 to 30,000 years before the earliest Clovis sites.

Description

Clovis points from the Rummells-Maske Cache Site in present-day Iowa

A hallmark of the toolkit associated with the Clovis culture is the distinctively shaped, fluted-stone spear point known as the Clovis point. The Clovis point is bifacial and typically fluted on both sides. Clovis tools were produced during a roughly 300-year period. Archaeologists do not agree on whether the widespread presence of these artifacts indicates the proliferation of a single people or the adoption of a superior technology by diverse population groups.

The culture is named after artifacts found between 1932 and 1936 at Blackwater Locality No. 1, an archaeological site between the towns of Clovis and Portales, New Mexico. These finds were deemed especially important due to their direct association with mammoth species and the extinct Bison antiquus. The in situ finds of 1936 and 1937 included four stone Clovis points, two long bone points with impact damage, stone blades, a portion of a Clovis blade core, and several cutting tools made on stone flakes. Clovis sites have since been identified throughout much of the contiguous United States, as well as in Mexico and parts of Central America, and even into northern South America.

Clovis people are generally accepted to have hunted mammoths, as well as extinct bison, mastodon, gomphotheres, ground sloths, tapir, Camelops, horse, and other smaller animals. More than 125 species of plants and animals are known to have been used by Clovis people in the portion of the Western Hemisphere they inhabited.

The oldest Clovis site in North America has been suggested to be El Fin del Mundo in northwestern Sonora, Mexico, discovered during a 2007 survey. At the site, remains of the gomphothere (elephant relative) Cuvieronius were found associated with Clovis points. In a 2013 study it was estimated to date to 13,390 years Before Present (BP). However, other authors have contested these dates, suggesting the site is likely younger than this, with a 2020 study finding that all reliably datable Clovis sites span from around 13,050 to 12,750 years BP.

Disappearance of Clovis

The most commonly held perspective on the end of the Clovis culture is that a decline in the availability of megafauna, combined with an overall increase in a less mobile population, led to local differentiation of lithic and cultural traditions across the Americas. After this time, Clovis-style fluted points were replaced by other fluted-point traditions (such as the Folsom culture) with an essentially uninterrupted sequence across North and Central America. An effectively continuous cultural adaptation proceeds from the Clovis period through the ensuing Middle and Late Paleoindian periods.

Whether the Clovis culture drove the mammoth, and other species, to extinction via overhunting – the Pleistocene overkill hypothesis – is still an open, and controversial, theory. It has also been hypothesized that the Clovis culture experienced decline in the wake of the Younger Dryas cold phase. This "cold shock", lasting roughly 1,500 years, affected many parts of the world, including North America. This appears to have been triggered by a vast amount of meltwater – possibly from Lake Agassiz – emptying into the North Atlantic, disrupting the thermohaline circulation.

The Younger Dryas Impact hypothesis, or Clovis Comet hypothesis, originally proposed that a large air burst or earth impact from a comet or comets initiated the Younger Dryas cold period about 12,900 years ago (10,900 14C years ago). This hypothesis has been largely contradicted, with research showing that most of the original findings cannot be replicated by other scientists. This hypothesis is criticized because of its misinterpretation of data and the lack of confirmatory evidence.

Proponents of the hypothesis have responded, disputing the accusation of irreproducibility of their findings. In 2013, a group from Harvard reported finding a layer of increased platinum (Pt) composition exactly at the Younger Dryas onset in a Greenland ice core, followed in 2017 by a report that the Pt spike had been also been found at an additional 11 continental Younger Dryas sites. Since then, the lead author of the Greenland Pt paper has coauthored a comprehensive rebuttal of the impact hypothesis which shows problems with dating and reveals that the Pt anomaly is later than the climate change and therefore could not have caused it.

Discovery

On 29 August 1927, the first in place evidence of Pleistocene humans seen by multiple archaeologists in the Americas was discovered near Folsom, New Mexico. At this site they found the first in situ Folsom point with the extinct B. antiquus bones. This confirmation of a human presence in the Americas during the Pleistocene inspired many people to start looking for evidence of early humans. Another earlier example at Folsom was discovered by George McJunkin, a cowboy, who found an ancient bison (Bison antiquus, an extinct relative of the American bison) skeleton in 1908 after a flash flood. The site was first excavated in 1926 under the direction of Harold Cook and Jesse Figgins.

In 1929, 19-year-old Ridgely Whiteman, who had been closely following the excavations in nearby Folsom in the newspaper, discovered the Clovis site near the Blackwater Draw in eastern New Mexico. Despite several earlier Paleoindian discoveries, the best documented evidence of the Clovis complex was collected and excavated between 1932 and 1937 near Clovis, New Mexico, by a crew under the direction of Edgar Billings Howard until 1935 and later by John Cotter from the Academy of Natural Sciences at the University of Pennsylvania. Howard's crew left their excavation in Burnet Cave, the first truly professionally excavated Clovis site, in August, 1932, and visited Whiteman and his Blackwater Draw site. By November, Howard was back at Blackwater Draw to investigate additional finds from a construction project.

The American Journal of Archaeology, in its January–March 1932 edition, mentions E. B. Howard's work in Burnet Cave, including the discovery of extinct fauna and a "Folsom type" point 4 ft below a Basketmaker burial. This brief mention of the Clovis point found in place predates any work done at the Dent site in Colorado. The reference is made to a slightly earlier article on Burnet Cave in The University Museum Bulletin of November, 1931.

The first report of professional work at the Blackwater Draw Clovis site was published in the November 25th issue of Science News (V22 #601) in 1932. The publications on Burnet Cave and Blackwater Draw directly contradict statements by several authors (for example see Haynes 2002:56 The Early Settlement of North America) that Dent, Colorado was the first excavated Clovis site. The Dent site, in Weld County, Colorado, was simply a fossil mammoth excavation in 1932. The first Dent Clovis point was found on November 5, 1932, and the in situ point was found July 7, 1933. The in situ Clovis point from Burnet Cave was excavated in late August, 1931 (and was reported in early 1932).

A Clovis burial site was found in Montana in 1968. It contained the remains of a two-year-old child they named Anzick-1, or Anzick boy. Analysis of DNA recovered from the remains indicates that Anzick-1 is more closely related to all of the indigenous peoples of the Americas than to any other group.

Clovis Paleo-Indians

Available genetic data show that the Clovis people are the direct ancestors of roughly 80% of all living Native American populations in North and South America, with the remainder descended from ancestors who entered in later waves of migration. As reported in February 2014, DNA from the 12,600-year-old remains of Anzick boy, found in Montana, has affirmed this connection to the peoples of the Americas. In addition, this DNA analysis affirmed genetic connections back to ancestral peoples of northeast Asia. This adds weight to the theory that peoples migrated across a land bridge from Siberia to North America.

Clovis First

This theory, known as "Clovis First", had been the predominant hypothesis among archaeologists in the second half of the 20th century. According to Clovis First, the people associated with the Clovis culture were the first inhabitants of the Americas. The primary support for this claim was that no solid evidence of pre-Clovis human habitation had been found. According to the standard accepted theory, the Clovis people crossed the Beringia land bridge over the Bering Strait from Siberia to Alaska during the ice age when there was a period of lowered sea levels, then made their way southward through an ice-free corridor east of the Rocky Mountains, located in present-day Western Canada, as the glaciers retreated.

This hypothesis came to be challenged by ongoing studies that suggest pre-Clovis human occupation of the Americas. In 2011, following the excavation of an occupation site at Buttermilk Creek, Texas, a group of scientists identified the existence "of an occupation older than Clovis." At the site in Buttermilk, archaeologists discovered evidence of hunter-gatherer group living and the making of projectile spear points, blades, choppers, and other stone tools. The tools found were made from a local chert and could be dated back to as early as 15,000 years ago.

According to researchers Michael Waters and Thomas Stafford of Texas A&M University, new radiocarbon dates place Clovis remains from the continental United States in a shorter time window beginning 450 years later than the previously accepted threshold (13,200 to 12,900 BP).

Recently, the scientific consensus has changed to acknowledge the presence of pre-Clovis cultures in the Americas, ending the "Clovis first" consensus.

Alternatives to Clovis First

Evidence of human habitation before Clovis

Map of the Americas showing pre-Clovis settlements

There have been a great number of archaeological findings across the Americas that pre-date the arrival of humans prior to 11,500–11,000 uncalibrated years before present (YBP). The Buttermilk Creek Complex, located in Salado, Texas, is a site where over 15,000 artifacts have been found. These artifacts are composed of a variety of small stone tool assemblages. These artifacts stratigraphically underlie previously excavated Clovis assemblages, meaning that they were deposited prior to the Clovis artifacts. These pre-Clovis assemblages are dated to between 13,200 and 15,500 years ago.

Predecessors of the Clovis people may have migrated south along the North American coastlines, although arguments exist for many migrations along several different routes. Radiocarbon dating of the Monte Verde site in Chile places Clovis-like culture there as early as 18,500 to 14,500 years ago. Remains found at the Channel Islands of California place coastal Paleoindians there 12,500 years ago. This suggests that the Paleoindian migration could have spread more quickly along the Pacific coastline, proceeding south, and that populations that settled along that route could have then begun migrations eastward into the continent.

The Pedra Furada sites in Brazil include a collection of rock shelters, which were used for thousands of years by diverse human populations. The first excavations yielded artifacts with carbon-14 dates of 48,000 to 32,000 years BP. Repeated analyses have confirmed this dating, carrying the range of dates up to 60,000 BP. Among the best analyzed archaeological levels are those dated between 32,160 ± 1000 years BP and 17,000 ± 400 BP. These claims have become an issue of contention between North American archaeologists and their South American and European counterparts, who disagree on whether it is conclusively proven to be an older human site.

In 2004, worked stone tools were found at Topper in South Carolina that have been dated by radiocarbon techniques possibly to 50,000 years ago. But, there is significant scholarly dispute regarding these dates. Scholars agree that evidence of humans at the Topper Site date back to 22,900 cal yr BP.

A more substantiated claim is that of Paisley Caves in Oregon, where rigorous carbon-14 and genetic testing appear to indicate that humans related to modern Native Americans were present in the caves over 1000 14C years before the earliest evidence of Clovis. Traces and tools made by another people, the "Western Stemmed" tradition, were documented.

A study published in Science presents strong evidence that humans occupied sites in Monte Verde in Chile, at the southern tip of South America, as early as 13,000 years ago. If this is true, then humans may have entered North America long before the Clovis culture, perhaps as long as 16,000 years ago.

The Tlapacoya site in Mexico is on the base of a remnant volcanic hill on the shore of the former Lake Chalco. Seventeen excavations along the base of Tlapacoya Hill between 1956 and 1973 uncovered piles of disarticulated bones of bear and deer that appeared to have been butchered, plus 2,500 flakes and blades presumably from the butchering activities, plus one unfluted spear point. All were found in the same stratum containing three circular hearths filled with charcoal and ash. Bones of many other animal species were also present, including horses and migratory waterfowl. Two uncalibrated radiocarbon dates on carbon from the hearths came in around 24,000 and 22,000 years ago. At another location, a prismatic microblade of obsidian was found in association with a tree trunk radiocarbon dated (uncalibrated) at roughly 24,000 years ago. This obsidian blade has recently been hydration dated by Joaquín García-Bárcena to 22,000 years ago. The hydration results were published in a seminal article that deals with the evidence for pre-Clovis habitation of Mexico.

Other sites, like White Sands National Park in New Mexico, also demonstrate archaeological findings that predate Clovis populations. In White Sands, excavated surfaces uncovered multiple in situ human footprints that were stratigraphically located between layers of material that were radio carbon dated to be from between 21,000 and 23,000 years ago. The findings from this site predate previous theories about the timeline of human migration of the Americas by several thousand years. Archaeologist working on the site believe that their findings indicates that humans had been present in the region since 23,000 years prior. This would mean that humans were occupying North America during the Last Glacial Maximum (LGM) – a theory that had previously been dismissed.

Though it is not currently the widely-accepted theory, these archaeological sites support alternative theories of early human migration such as a coastal migration route or the Solutrean hypothesis. This archaeological evidence is also supported by genetic mapping of ancestral mitochondrial DNA.

Archaeological sites that predate Clovis that are well documented include:

Coastal migration route

Studies of the mitochondrial DNA of First Nations/Native Americans published in 2007 suggest that the people of the New World may have diverged genetically from Siberians as early as 20,000 years ago, far earlier than the standard theory suggests. According to one alternative theory, the Pacific coast of North America may have been free of ice, allowing the first peoples in North America to come down this route prior to the formation of the ice-free corridor in the continental interior. No evidence has yet been found to support this hypothesis except that genetic analysis of coastal marine life indicates diverse fauna persisting in refugia throughout the Pleistocene ice ages along the coasts of Alaska and British Columbia; these refugia include common food sources of coastal aboriginal peoples, suggesting that a migration along the coastline was feasible at the time. Some early sites on the coast, for example Namu, British Columbia, exhibit maritime focus on foods from an early point with substantial cultural continuity.

This lack of evidence is likely due to the change in sea level since the time of migration. During the Last Glacial Maximum the global sea level was more than 400 feet lower than it is today. Starting about 15,000 years ago, glaciers began retreating and sea levels began rising. Sea levels reached their current level about 8,000 years ago and have fluctuated slightly since then. This drastic change in sea level may prevent the discovery of sites located along what was once the coastline and is now located under over 400 feet of water. As of now, genetic analysis is one of the only means of tracking early human movements.

In February 2014, researchers reported on their DNA analysis of the remains of Anzick boy (referred to as Anzick-1) of Montana, the oldest skeleton found in the Americas and dated to 12,600 years ago. They found the mtDNA to be D4h3a, "one of the rare lineages associated with Native Americans." This was the same as the mtDNA associated with current coastal populations in North and South America. The study team suggest that finding this genetic evidence so far inland shows that "current distribution of genetic markers are not necessarily indicative of the movement or distribution of peoples in the past." The Y haplotype was found to be Q-L54*(xM3). Further testing found that Anzick-1 was most closely related to Native American populations (see below).

Solutrean hypothesis

The controversial Solutrean hypothesis proposed in 1999 by Smithsonian archaeologist Dennis Stanford and colleague Bruce Bradley (Stanford and Bradley 2002), suggests that the Clovis people could have inherited technology from the Solutrean people who lived in southern Europe 21,000–15,000 years ago, and who created the first Stone Age artwork in present-day southern France. The link is suggested by the similarity in technology between the projectile points of the Solutreans and those found at Clovis (and pre-Clovis) sites. Its proponents point to tools found at various pre-Clovis sites in eastern North America (particularly in the Chesapeake Bay region) as progenitors of Clovis-style tools. The model envisions these people making the crossing in small watercraft via the edge of the pack ice in the North Atlantic Ocean that then extended to the Atlantic coast of France, using skills similar to those of the modern Inuit, making landfall somewhere around the then-exposed Grand Banks of the North American continental shelf.

In a 2008 study of the relevant paleoceanographic data, Kieran Westley and Justin Dix concluded that "it is clear from the paleoceanographic and paleo-environmental data that the Last Glacial Maximum (LGM) North Atlantic does not fit the descriptions provided by the proponents of the Solutrean Atlantic Hypothesis. Although ice use and sea mammal hunting may have been important in other contexts, in this instance, the conditions militate against an ice-edge-following, maritime-adapted European population reaching the Americas."

University of New Mexico anthropologist Lawrence G. Straus, a primary critic of the Solutrean hypothesis, points to the theoretical difficulty of the ocean crossing, a lack of Solutrean-specific features in pre-Clovis artifacts, as well as the lack of art (such as that found at Lascaux in France) among the Clovis people, as major deficiencies in the Solutrean hypothesis. The 3,000 to 5,000 radiocarbon year gap between the Solutrean period of France and Spain and the Clovis of the New World also makes such a connection problematic. In response, Bradley and Stanford contend that it was "a very specific subset of the Solutrean who formed the parent group that adapted to a maritime environment and eventually made it across the north Atlantic ice-front to colonize the east coast of the Americas" and that this group may not have shared all Solutrean cultural traits.

Genetic evidence of east/west dichotomy

Mitochondrial DNA analysis in 2014 found that members of some native North American tribes have a maternal ancestry (called haplogroup X) linked to the maternal ancestors of some present-day individuals in western Asia and Europe, albeit distantly. This has also provided some support for pre-Clovis models. More specifically, a variant of mitochondrial DNA called X2a found in many Native Americans has been traced to western Eurasia, while not being found in eastern Eurasia.

Mitochondrial DNA analysis of Anzick-1 concluded that the boy belonged to what is known as haplogroup or lineage D4h3a. This finding is important because the D4h3a line is considered to be a lineage "founder", belonging to the first people to reach the Americas. Although rare in most of today's Native Americans in the US and Canada, D4h3a genes are more common among native peoples of South America, far from the site in Montana where Anzick-1 was buried. This suggests a greater genetic complexity among Native Americans than previously thought, including an early divergence in the genetic lineage 13,000 years ago. One theory suggests that after crossing into North America from Siberia, a group of the first Americans, with the lineage D4h3a, moved south along the Pacific coast and, over thousands of years, into Central and South America, while others may have moved inland, east of the Rocky Mountains. The apparent early divergence between North American and Central plus South American populations may or may not be associated with post-divergence gene flow from a more basal population into North America; however, analysis of published DNA sequences for 19 Siberian populations does not favor the latter scenario.

Spearheads and DNA found at the Paisley Caves site in Oregon suggest that North America was colonized by more than one culture, and that the Clovis culture was not the first. There is evidence to suggest an east/west dichotomy, with the Clovis culture located to the east.

But in 2014, the autosomal DNA of a 12,500+-year-old infant from Montana was sequenced. The DNA was taken from a skeleton referred to as Anzick-1, found in close association with several Clovis artifacts. Comparisons indicate strong affinities with DNA from Siberian sites, and virtually rule out close affinity with European sources (the "Solutrean hypothesis"). The DNA shows strong affinities with all existing Native American populations, which indicated that each of them derives from an ancient population that lived in or near Siberia, the Upper Palaeolithic Mal'ta population. Mal'ta belonged to Y-DNA haplogroup R and mitochrondrial macrohaplogroup U.

The data indicate that Anzick-1 is from a population directly ancestral to present South American and Central American Native American populations. This rules out hypotheses which posit that invasions subsequent to the Clovis culture overwhelmed or assimilated previous migrants into the Americas. Anzick-1 is less closely related to present North American Native American populations (including a Yaqui genetic sample), suggesting that the North American populations are basal to Anzick-1 and Central and South American populations. The apparent early divergence between North American and Central plus South American populations might be due to post-divergence gene flow from a more basal population into North America; however, analysis of published DNA sequences of 19 Siberian populations do not suggest this scenario. Anzick-1 belonged to Y-haplogroup Q-L54(xM3), which is by far the largest haplogroup among Native Americans.

The issue is complicated by the discovery that there was DNA backflow from North America to North Asia during the period in question.

Megafaunal migrations

Although there is no archaeological evidence that can be used to directly support a coastal migration route during the Last Glacial Maximum, genetic analysis has been used to support this thesis. In addition to human genetic lineage, megafaunal DNA linage can be used to trace movements of megafauna – large mammalian – as well as the early human groups who hunted them.

Bison, a type of megafauna, have been identified as an ideal candidate for the tracing of human migrations out of Europe because of both their abundance in North America as well as being one of the first megafauna for which ancient DNA was used to trace patterns of population movement. Unlike other types of fauna that moved between the Americas and Eurasia (mammoths, horses, and lions), Bison survived the North American extinction event that occurred at the end of the Pleistocene. Their genome, however, contains evidence of a bottleneck – something that can be used to test hypothesis on migrations between the two continents. Early human groups were largely nomadic, relying on following food sources for survival. Mobility was part of what made humans successful. As nomadic groups, early humans likely followed the food from Eurasia to the Americas – part of the reason why tracing megafaunal DNA is so helpful for garnering insight to these migratory patterns.

The grey wolf originated in the Americas and migrated into Eurasia prior to the Last Glacial Maximum – during which it was believed that remaining populations of the grey wolf residing in North America faced extinction and were isolated from the rest of the population. This, however, may not be the case. Radiocarbon dating of ancient grey wolf remains found in permafrost deposits in Alaska show a continuous exchange of population from 12,500 radiocarbon years BP to beyond radiocarbon dating capabilities. This indicates that there was viable passage for grey wolf populations to exchange between the two continents.

These faunas' ability to exchange populations during the period of the Last Glacial Maximum along with genetic evidence found from early human remains in the Americas provides evidence to support pre-Clovis migrations into the Americas.

Other sites

Mammuthus primigenius, a bearing tool cast skeleton produced and distributed by Triebold Paleontology Incorporated in Woodland Park, Colorado

Other sites include (in approximate reverse chronological order):

  • Pedra Furada, Serra da Capivara National Park in Piauí, Brazil. Site with evidence of non-Clovis human remains, a rock painting rupestre art drawings from at least 12,000–6,000 BP. Hearth samples C-14 dates of 48–32,000 BP were reported in a Nature article (Guidon and Delibrias 1986). New hearth samples with ABOX dates of 54,000 BP were reported in the Quaternary Science Reviews. Paleoindian components found here, have been challenged by American researchers such as Meltzer, Adovasio, and Dillehay.
  • The Monte Verde site in Chile, was occupied from 14,800 years BP, with bones and other finds dating on average 12,500 yrs BP. The earliest finds at the site were from between 32,840 and 33,900 years BP, but are controversial. 14C yr BP)
  • The Bluefish Caves site in Yukon, Canada, contains bones with evidence of human cut-marks which demonstrates a human presence as early as 24,000 yr BP. The Bluefish caves are currently the oldest archaeological site in North America and offers evidence regarding the Beringia Standstill hypothesis, which states a genetically isolated human population remained in the area during the last glacial maximum and then traveled within North America and South America after the glaciers receded.
  • Lagoa Santa, in Minas Gerais in Brazil, is erroneously asserted to be Clovis age or even possibly Pre-Clovis in age. The recent discussion of this site (specifically Lapa Vermelha IV) and the Luzia skull, reportedly 11,500 years old by Neves and Hubb, makes it clear that this date is a chronological date in years Before Present and not a raw radiocarbon date in eastern Brazil. Clovis sites mostly date between 11,500 and 11,000 radiocarbon years which means 13,000 years before present at a minimum. "Luzia" is at least 1,000 years younger than Clovis and Lapa Vermelha IV should not be considered a Pre-Clovis site.
  • Cueva del Milodón, in Patagonian Chile dates at least as early as 10,500 BP. This is a site found particularly early in the New World hunt for Early Man, circa 1896, and needs additional basic research, but 10,500 B.P. would be 1,500 years younger than Clovis, or if the dating is 10,500 RCYBP [radiocarbon years before present], it would still be roughly 500–700 years younger than Clovis. In either case this should not be considered a Pre-Clovis site.
  • Cueva Fell and Pali Aike Crater sites in Patagonia, with hearths, stone tools and other elements of human habitation dating to at least as early as 11,000 BP.
  • The Big Eddy Site in southwestern Missouri contains several claimed pre-Clovis artifacts or geofacts. In situ artifacts have been found in this well-stratified site in association with charcoal. Five different samples have been AMS dated to between 11,300 and 12,675 BP (Before Present).
  • Taima Taima, Venezuela has cultural material very similar to Monte Verde II, dating to 12,000 years BP. Recovered artifacts of the El Jobo complex in direct association with the butchered remains of a juvenile mastodon. Radiocarbon dates on associated wood twigs indicate a minimum age of 13,000 years before the present for the mastodon kill, a dating significantly older than that of the Clovis complex in North America.
  • The Page–Ladson site, on the Aucilla River in Florida, has yielded evidence that a mastodon was butchered by people 15,550 calendar years BP. A cut mastodon tusk dated to 12,300 years BP had previously been found near a few in situ artifacts of similar age. A test pit in 1983 yielded elephant bones, bone tools, and chips from tool making. Radiocarbon dating of organic material from the pit yielded dates from 13,000 to 11,700 years BP.
  • The Schaefer and Hebior mammoth sites in Kenosha County, Wisconsin indicate exploitation of this animal by humans. The Schaefer Mammoth site has over 13 highly purified collagen AMS dates and 17 dates on associated wood, dating it to 12,300–12,500 radiocarbon years before the present. Hebior has two AMS dates in the same range. Both animals show conclusive butchering marks and associated non-diagnostic tools.
  • A site in Walker, Minnesota with stone tools, alleged to be from 13,000 to 15,000 years old based on surrounding geology, was discovered in 2006. However, further examination suggests that the site does not represent a human occupation.
  • In a 2011 article in Science, Waters et al. 2011 describe an assemblage of 15,528 lithic artifacts from the Debra L. Friedkin site west of Salado, Texas. These artifacts (including 56 tools, 2,268 macrodebitage and 13,204 microdebitage) define the Buttermilk Creek Complex formation, which stratigraphically underlies a Clovis assemblage. While carbon dating could not be used to directly date the artifacts, 49 samples from the 20 cm Buttermilk floodplain sedimentary clay layer in which the artifacts were embedded were dated using optically stimulated luminescence (OSL). Eighteen OSL ages, ranging from 14,000 to 17,500 ka were obtained from this layer. The authors report "the most conservative estimate" of the age of the Buttermilk clays range from 13,200 to 15,500 ka, based on the minimum age represented by each of the 18 OSL ages.
  • Human coprolites have been found in Paisley Caves in Oregon, carbon dated at 14,300 years ago. Genetic analysis revealed that the coprolites contained mtDNA haplogroups A2 and B2, two of the five major Native American mtDNA haplogroups.
  • The Mud Lake site, in Kenosha County, Wisconsin, consists of the foreleg of a juvenile mammoth recovered in the 1930s. Over 100 stone tool butchering marks are found on the bones. Several purified collagen AMS dates show the animal to be 13,450 RCYBP with a range of plus or minus 1,500 RCYBP variance.
  • Meadowcroft Rockshelter in southwestern Pennsylvania, excavated between 1973 and 78, has evidence of occupancy dating back from 16,000 to 19,000 years ago.
  • Cactus Hill in southern Virginia, with artifacts such as unfluted bifacial stone tools with dates ranging from c. 15,000 to 17,000 years ago.
  • Sixty-eight stone and bone tools discovered in an orchard in East Wenatchee, Washington in 1987, excavated in 1988 and 1990. Five of the Clovis points are on display at the Wenatchee Valley Museum & Cultural Center.
  • Serpentine Hot Springs in the Seward Peninsula in Alaska, excavated 2010–2011, with evidence of what appears to have been a backflow in migration of Clovis people who may have moved north through the ice-free corridor to settle in Western Alaska on the Bering Sea. The spear points found were a modification of Clovis, either from a northward migration or of the adoption of the technology by indigenous inhabitants.
  • Pendejo Cave is a geological feature and archaeological site located in southern New Mexico. Archaeologist Richard S. MacNeish claimed that human occupation of the cave pre-dates by tens of thousands of years the Clovis Culture.
  • The Cerutti Mastodon site is a paleontological and possible archeological site in San Diego County, California. In 2017, researchers announced that broken mastodon bones at the site had been dated to around 130,700 years ago. Others have disputed the claim that humans had modified the cobbles found at the site or had broken the bones.

Operator (computer programming)

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