Mastodon

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Mastodon 

Mastodon Temporal range: Early Pliocene – Late Pleistocene, 5.3–0.011 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Mounted M. americanum skeleton (the "Warren mastodon"), AMNH
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Family:	†Mammutidae
Genus:	†Mammut Blumenbach, 1799
Type species
†Elephas americanum Kerr, 1792
Species
†M. americanum (Kerr, 1792) †M. cosoensis Schultz, 1937 †M. matthewi Osborn, 1921 †M. pacificus Dooley et al., 2019 †M. raki Frick, 1933
The inferred range of Mammut (Eurasian range includes that of Zygolophodon borsoni, whose genus assignment is uncertain, and M. matthewi)
Synonyms
Mastodon Cuvier, 1817 Tetracaulodon Godman, 1830 Missourium Koch, 1840 Leviathan Koch, 1841 (Emend. Koch, 1843) Pliomastodon Osborn, 1926

A mastodon (mastós 'breast' + odoús 'tooth') is any proboscidean belonging to the extinct genus Mammut (family Mammutidae) that inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago. Mastodons lived in herds and were predominantly forest-dwelling animals. They survived on a mixed diet and obtained food by browsing and grazing, somewhat similar to modern elephants, but probably with greater emphasis on browsing

M. americanum, the American mastodon, and M. pacificus, the Pacific mastodon, are the youngest and best-known species of the genus. Mastodons disappeared from North America as part of a mass extinction of most of the Pleistocene megafauna, widely believed to have been caused by a combination of climate changes at the end of the Pleistocene combined with overexploitation by Clovis hunters.

History

Exhuming the First American Mastodon, 1806 painting by Charles Willson Peale

A Dutch tenant farmer found the first recorded remnant of Mammut, a tooth some 2.2 kg (5 lb) in weight, in the village of Claverack, New York, in 1705. The mystery animal became known as the "incognitum". In 1739 French soldiers at present-day Big Bone Lick State Park, Kentucky, found the first bones to be collected and studied scientifically. They carried them to the Mississippi River, from where they were transported to the National Museum of Natural History in Paris. Similar teeth were found in South Carolina, and some of the African slaves there supposedly recognized them as being similar to the teeth of African elephants. There soon followed discoveries of complete bones and tusks in Ohio. People started referring to the "incognitum" as a "mammoth", like the ones that were being dug out in Siberia – in 1796 the French anatomist Georges Cuvier proposed the radical idea that mammoths were not simply elephant bones that had been somehow transported north, but a species which no longer existed. Johann Friedrich Blumenbach assigned the scientific name Mammut to the American "incognitum" remains in 1799, under the assumption that they belonged to mammoths. Other anatomists noted that the teeth of mammoths and elephants differed from those of the "incognitum", which possessed rows of large conical cusps, indicating that they were dealing with a distinct species. In 1817 Cuvier named the "incognitum" Mastodon.

Cuvier assigned the name mastodon (or mastodont) - meaning "breast tooth" (Ancient Greek: μαστός "breast" and ὀδούς, "tooth"), - for the nipple-like projections on the crowns of the molars.

Taxonomy

Mastodon as a genus name is obsolete; the valid name is Mammut, as that name preceded Cuvier's description, making Mastodon a junior synonym. The change was met with resistance, and authors sometimes applied "Mastodon" as an informal name; consequently it became the common term for members of the genus.

Species include:

• M. americanum, the American mastodon, is one of the best known and among the last species of Mammut. Its earliest occurrences date from the early-middle Pliocene (early Blancan stage). It was formerly regarded (see below) as having a continent-wide distribution, especially during the Pleistocene epoch, known from fossil sites ranging from present-day Alaska, Ontario and New England in the north, to Florida, southern California, and as far south as Honduras. The American mastodon has been widely thought to have resembled a woolly mammoth in appearance. However, consideration of the long tail (usually present in animals living in warm climates), size, body mass and environment implies the animal was not similarly hairy, and there is scant preserved evidence of body hair (what little has been recovered suggests a semiaquatic lifestyle). It had tusks that sometimes exceeded 5 m (16 ft) in length; they curved upwards, but less dramatically than those of the woolly mammoth. Its main habitat was cold spruce woodlands, and it is believed to have browsed in herds. It became extinct at the end of the Pleistocene approximately 11,000 years ago.
• M. matthewi — found in the Snake Creek Formation of Nebraska, dating to the late Hemphillian. Some authors consider it practically indistinguishable from M. americanum. There is one report of it in China.
• M. pacificus — based on a 2019 analysis, Pleistocene specimens from California and southern Idaho have been transferred from M. americanum to this new species. It differs from the eastern population in having narrower molars, six as opposed to five sacral vertebrae, a thicker femur, and a consistent absence of mandibular tusks.
• M. raki — Its remains were found in the Palomas Formation, near Truth or Consequences, New Mexico, dating from the early-middle Pliocene, between 4.5 and 3.6 Ma. It coexisted with Equus simplicidens and Gigantocamelus and differs from M. americanum in having a relatively longer and narrower third molar, similar to the description of the defunct genus Pliomastodon, which supports its arrangement as an early species of Mammut. However, like M. matthewi, some authors do not consider it sufficiently distinct from M. americanum to warrant its own species.
• M. cosoensis — found in the Coso Formation of California, dating to the Late Pliocene, originally a species of Pliomastodon, it was later assigned to Mammut.

Since a tentative 1977 report of M. matthewi in China, there have been no reports of currently recognized Mammut species outside of North America according to Paleobiology database (which does not recognize M. borsoni). However, the status of Mammut or Zygolophodon borsoni in the literature appears equivocal.

Evolution

Comparison of woolly mammoth (L) and American mastodon (R)

 

Excavation of a specimen in a golf course in Heath, Ohio, 1989

Mammut is a genus of the extinct family Mammutidae, closely related to the proboscidean family Elephantidae (mammoths and elephants), from which it originally diverged approximately twenty-seven million years ago. The following cladogram shows the placement of the American mastodon among other proboscideans, based on hyoid characteristics:

	Mammut americanum (American mastodon)       Gomphotherium sp.       Stegodon zdanskyi       Loxodonta africana (African elephant)       Elephas maximus (Asian elephant)     Mammuthus columbi (Columbian mammoth)

Over the years, several fossils from localities in North America, Africa and Asia have been attributed to Mammut, but only the North American remains have been named and described, one of them being M. furlongi, named from remains found in the Juntura Formation of Oregon, dating from the late Miocene. However, it is no longer considered valid, leaving only five valid species.

A complete mitochondrial DNA (mtDNA) sequence has been obtained from the tooth of an M. americanum skeleton found in permafrost in northern Alaska. The remains are thought to be 50,000 to 130,000 years old. This sequence has been used as an outgroup to refine divergence dates in the evolution of the Elephantidae. The rate of mtDNA sequence change in proboscideans was found to be significantly lower than in primates.

A 2020 analysis of mtDNA from American mastodon remains collected in eastern Beringia indicated they belonged to two genetically divergent clades. The clades were dated to different interglacials, suggesting a repeating pattern of colonization during an interglacial followed by extirpation during the subsequent glacial advance. The Beringian clades had less genetic diversity than populations present south of the ice sheets, suggesting they were founded by relatively small migrating populations.

Description

Restoration of an American mastodon

Modern reconstructions based on partial and skeletal remains reveal that mastodons were very similar in appearance to elephants and, to a lesser degree, mammoths, though not closely related to either one. Compared to mammoths, mastodons had shorter legs and a longer body and were more heavily muscled, a build similar to that of the current Asian elephants. The average body size of the species M. americanum was around 2.3 m (7 ft 7 in) in height at the shoulders, corresponding to a large female or a small male; large males were up to 2.8 m (9 ft 2 in) in height. Among the largest male specimens, the 35-year-old AMNH 9950 was 2.89 m (9.5 ft) tall and weighed 7.8 tonnes (7.7 long tons; 8.6 short tons), while another was 3.25 m (10.7 ft) tall and weighed 11 tonnes (11 long tons; 12 short tons).

American mastodon molars at the State Museum of Pennsylvania

As in modern elephants, the females were smaller than the males. They had a low and long skull with long curved tusks, with those of the males being more massive and more strongly curved. Mastodons had cusp-shaped teeth, very different from mammoth and elephant teeth (which have a series of enamel plates), well-suited for chewing leaves and branches of trees and shrubs.

Mastodons are typically depicted with a thick woolly mammoth-like coat of hair, but there is no preserved evidence for this.

Paleobiology

Social behavior

M. pacificus female and calf at the George C. Page Museum

Based on the characteristics of mastodon bone sites, it can be inferred that, as in modern proboscideans, the mastodon social group consisted of adult females and young, living in bonded groups called mixed herds. The males abandoned the mixed herds once reaching sexual maturity and lived either alone or in male bond groupings. As in modern elephants, there probably was no seasonal synchrony of mating activity, with both males and females seeking out each other for mating when sexually active.

M. americanum male and female, University of Michigan

Diet

Mastodons have been characterized as predominantly browsing animals. Of New World proboscids, they appear to have been the most consistent in browsing rather than grazing, consuming C₃ as opposed to C₄ plants, and in occupying closed forests versus more open habitats. This dietary inflexibility may have prevented them from invading South America during the Great American Interchange, due to the need to cross areas of grassland to do so. Most accounts of gut contents have identified coniferous twigs as the dominant element in their diet. Other accounts (e.g., the Burning Tree mastodon) have reported no coniferous content and suggest selective feeding on low, herbaceous vegetation, implying a mixed browsing and grazing diet, with evidence provided by studies of isotopic bone chemistry indicating a seasonal preference for browsing. Study of mastodon teeth microwear patterns indicates that mastodons could adjust their diet according to the ecosystem, with regionally specific feeding patterns corresponding to boreal forest versus cypress swamps, while a population at a given location was sometimes able to maintain its dietary niche through changes in climate and browse species availability.

Distribution and habitat

Restoration of an American mastodon herd by Charles R. Knight

The range of most species of Mammut is unknown as their occurrences are restricted to few localities, the exception being the American mastodon (M. americanum), which is one of the most widely distributed Pleistocene proboscideans in North America. M. americanum fossil sites range in time from the Blancan to Rancholabrean faunal stages and in locations from as far north as Alaska, as far east as Florida, and as far south as the state of Puebla in central Mexico, with an isolated record from Honduras, probably reflecting the results of the maximum expansion achieved by the American mastodon during the Late Pleistocene. A few isolated reports tell of mastodons being found along the east coast up to the New England region, with high concentrations in the Mid-Atlantic region. There is strong evidence indicating that the members of Mammut were forest dwelling proboscideans, predominating in woodlands and forests, and browsed on trees and shrubs. They apparently did not disperse southward to South America, it being speculated that this was because of a dietary specialization on a particular type of vegetation.

Extinction

Fossil evidence indicates that mastodons probably disappeared from North America about 10,500 years ago as part of a mass extinction of most of the Pleistocene megafauna that is widely believed to have been a result of human hunting pressure. The latest Paleo-Indians entered the Americas and expanded to relatively large numbers 13,000 years ago, and their hunting may have caused a gradual attrition of the mastodon population. Analysis of tusks of mastodons from the American Great Lakes region over a span of several thousand years prior to their extinction in the area shows a trend of declining age at maturation; this is contrary to what one would expect if they were experiencing stresses from an unfavorable environment, but is consistent with a reduction in intraspecific competition that would result from a population being reduced by human hunting.

On the other hand, environmental DNA sequencing indicates that disappearance of megafaunal DNA in North America correlates in time with major changes in plant DNA, suggesting a key role of climate change. Modeling based on the whole of the proboscid fossil record also suggests climate was the more important factor, though with human hunting imposing a "double jeopardy" on mastodons and their kin.

 

Proboscidea

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Proboscidea 

Proboscidea Temporal range: Middle Paleocene-Holocene 60.0–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
African bush elephant, Loxodonta africana
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Clade:	Tethytheria
Order:	Proboscidea Illiger, 1811
Subclades
†Eritherium †Moeritherium †Saloumia †Plesielephantiformes Elephantiformes

The Proboscidea (/prɒbəˈsɪdiːə/, from the Greek προβοσκίς and the Latin proboscis) are a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. From the mid-Miocene onwards, most proboscideans were very large. The largest land mammal of all time may have been a proboscidean; Palaeoloxodon namadicus was up to 5.2 m (17.1 ft) at the shoulder and may have weighed up to 22 t (24.3 short tons), almost double the weight of some sauropods like Diplodocus carnegii. The largest extant proboscidean is the African bush elephant, with a record of size of 4 m (13.1 ft) at the shoulder and 10.4 t (11.5 short tons). In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans.

Elephants are the largest existing land animals. Three species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Elephantidae is the only surviving family of the order Proboscidea; extinct members include the mastodons. The family Elephantidae also contains several extinct groups, including the mammoths and straight-tusked elephants. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears, and convex or level backs. Distinctive features of all elephants include a long proboscis called a trunk, tusks, large ear flaps, massive legs, and tough but sensitive skin. The trunk is used for breathing, bringing food and water to the mouth, and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. The pillar-like legs carry their great weight.

Evolution

The earliest known proboscidean is Eritherium, followed by Phosphatherium, a small animal about the size of a fox. Both date from late Paleocene deposits of Morocco.

Woolly mammoth and American mastodon

Proboscideans evolved in Africa, where they increased in size and diversity during the Eocene and early Oligocene. Proboscideans have evolved greatly over time through three major forms of radiation: radiation of primitive Lophodont forms, radiation of gomphotheres and stegodons, and radiation of elepphantidae. These forms of radiation have illustrated that proboscideans characteristics such as trunk, large ears, tusks, flaps, and huge ears have evolved and were appearing late in the modern form. Several primitive families from these epochs have been described, including the Numidotheriidae, Moeritheriidae, and Barytheriidae, all found exclusively in Africa. The Anthracobunidae from the Indian subcontinent were also believed to be a family of proboscideans, but were excluded from the Proboscidea by Shoshani and Tassy (2005) and have more recently been assigned to the Perissodactyla. When Africa became connected to Europe and Asia after the shrinking of the Tethys Sea, proboscideans migrated into Eurasia, with some families eventually reaching the Americas. Proboscideans found in Eurasia as well as Africa include the Deinotheriidae, which thrived during the Miocene and into the early Quaternary, Stegolophodon, an early genus of the disputed family Stegodontidae; the highly diverse Gomphotheriidae and Amebelodontidae; and the Mammutidae, or mastodons.

Most proboscideans are now extinct, including all species endemic to the Americas, Europe, and northern Asia. Many of these extinctions occurred during or shortly after the last glacial period. Recently extinct species include the gomphotheres in the Americas, the American mastodon of family Mammutidae in North America, numerous stegodonts in Asia, the mammoths throughout the Northern Hemisphere, and several species of dwarf elephants found on various islands scattered around the world.

Classification

[[DJS -- see Wiki article above for an unranked taxonomy of proboscidean genera as of 2019 --]]

Elephantidae

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Elephantidae 

 

Elephantidae Temporal range: Pliocene–Holocene PreꞒ Ꞓ O S D C P T J K Pg N
A male Asian elephant (Elephas maximus) in the wild at Bandipur National Park in India
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Superfamily:	Elephantoidea
Family:	Elephantidae Gray, 1821
Type genus
Elephas Linnaeus, 1758
Genera
Elephas Linnaeus, 1758 Loxodonta Anonymous, 1827 Mammuthus Brookes, 1828 † Palaeoloxodon Matsumoto, 1925 † Primelephas Maglio, 1970 † Stegotetrabelodon Petrocchi, 1941†[1]
Synonyms
Elephasidae Lesson, 1842

Elephantidae is a family of large, herbivorous proboscidean mammals collectively called elephants and mammoths. These are terrestrial large mammals with a snout modified into a trunk and teeth modified into tusks. Most genera and species in the family are extinct. Only two genera, Loxodonta (African elephants) and Elephas (Asiatic elephants), are living.

The family was first described by John Edward Gray in 1821, and later assigned to taxonomic ranks within the order Proboscidea. Elephantidae has been revised by various authors to include or exclude other extinct proboscidean genera.

Classification

See also: List of elephant species and Elephants

 

"Man, and the elephant" plate from Hawkins' A comparative view of the human and animal frame, 1860

 

Skeleton of Mammuthus meridionalis at the French Museum of Natural History

Scientific classification of Elephantidae taxa embraces an extensive record of fossil specimens, over millions of years, some of which existed until the end of the last ice age. Some species were extirpated more recently. The discovery of new specimens and proposed cladistics have resulted in systematic revisions of the family and related proboscideans.

Elephantids are classified informally as the elephant family, or in a paleobiological context as elephants and mammoths. The common name elephant primarily refers to the living taxa, the modern elephants, but may also refer to a variety of extinct species, both within this family and in others. Other members of the Elephantidae, especially members of the genus Mammuthus, are commonly called mammoths.

The family diverged from a common ancestor of the mastodons of Mammutidae. The classification of proboscideans is unstable and has been frequently revised.

The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on a 2007 study of hyoid characteristics:

Elephantidae	Elephantinae   Loxodontini Loxodonta (2 species)   (African elephants)     Elephantini   †Palaeoloxodontina         †Palaeoloxodon     Elephantina   Elephas (3~6 subspecies)   (Asian elephants)       †Mammuthus   (Mammoths)

The most accurate phylogenetic tree of the elephants and mammoths as of 2010

However, a 2017 study of mitochondrial and nuclear DNA placed Palaeoloxodon as more closely related to Loxodonta (in particular, the African forest elephant) than to Elephantina.

The systematics of the living subspecies and species of the modern elephants has undergone several revisions. A list of the extant Elephantidae includes:

Elephantidae

Loxodonta (African)

L. africana African bush elephant

L. cyclotis African forest elephant

Elephas (Asiatic)

E. maximus Asian elephant

E. m. maximus Sri Lankan elephant

E. m. indicus Indian elephant

E. m. sumatranus Sumatran elephant

E. m. borneensis Borneo elephant

Evolutionary history

Evolution of elephants from the ancient Eocene (bottom) to the modern day (top)

Although the fossil evidence is uncertain, by comparing genes, scientists have discovered evidence that elephantids and other proboscideans share a distant ancestry with Sirenia (sea cows) and Hyracoidea (hyraxes). These have been assigned, along with the extinct demostylians and embrithopods, to the clade Paenungulata. In the distant past, members of the various hyrax families grew to large sizes, and the common ancestor of all three modern families is thought to have been some kind of amphibious hyracoid. One hypothesis is that these animals spent most of their time under water, using their trunks like snorkels for breathing. Modern elephants have this ability and are known to swim in that manner for up to six hours and 50 km (31 mi).

In the past, a much wider variety of genera and species was found, including the mammoths and stegodons.

Mammoth

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Mammoth 

Mammoth Temporal range: Early Pliocene to Late Holocene, 5–0.0037 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Columbian mammoth in the Page Museum in Los Angeles.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Proboscidea
Family:	Elephantidae
Subfamily:	Elephantinae
Tribe:	Elephantini
Genus:	†Mammuthus Brookes, 1828
Type species
†Elephas primigenius Blumenbach, 1799
Species
†M. africanavus †M. columbi †M. creticus †M. exilis †M. lamarmorai †M. meridionalis †M. primigenius (formerly Elephas primigenius) †M. rumanus †M. subplanifrons †M. trogontherii
Synonyms
Archidiskodon Pohling, 1888 Parelephas Osborn, 1924 Mammonteus

A mammoth is any species of the extinct elephantid genus Mammuthus, one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks and, in northern species, a covering of long hair. They lived from the Pliocene epoch (from around 5 million years ago) into the Holocene at about 4,000 years ago, and various species existed in Africa, Europe, Asia, and North America. They were members of the family Elephantidae, which also contains the two genera of modern elephants and their ancestors. Mammoths are more closely related to living Asian elephants than African Elephants.

The oldest representative of Mammuthus, the South African mammoth (M. subplanifrons), appeared around 5 million years ago during the early Pliocene in what is now southern and eastern Africa. Descendant species of these mammoths moved north and continued to propagate into numerous subsequent species, eventually covering most of Eurasia before extending into the Americas at least 600,000 years ago. The last species to emerge, the woolly mammoth (M. primigenius), developed about 400,000 years ago in East Asia, with some surviving on Russia's Wrangel Island in the Arctic Ocean until as recently as roughly 3,700 to 4,000 years ago, still extant during the construction of the Great Pyramid of ancient Egypt.

Evolution

The earliest known proboscideans, the clade that contains the elephants, existed about 55 million years ago around the Tethys Sea area. The closest relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae is known to have existed six million years ago in Africa, and includes the living elephants and the mammoths. Among many now extinct clades, the mastodon is only a distant relative of the mammoths, and part of the separate Mammutidae family, which diverged 25 million years before the mammoths evolved.

The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on hyoid characteristics: [[DJS -- See Wiki article above for cladogram]].

Comparison of a woolly mammoth (left) and an American mastodon (right).

Since many remains of each species of mammoth are known from several localities, it is possible to reconstruct the evolutionary history of the genus through morphological studies. Mammoth species can be identified from the number of enamel ridges on their molars; the primitive species had few ridges, and the amount increased gradually as new species evolved and replaced the former ones. At the same time, the crowns of the teeth became longer, and the skulls become higher from top to bottom and shorter from the back to the front over time to accommodate this.

Tooth of M. africanavus, one of the earliest known species of mammoth, from North Africa.

The first known members of the genus Mammuthus are the African species Mammuthus subplanifrons from the Pliocene and Mammuthus africanavus from the Pleistocene. The former is thought to be the ancestor of later forms. Mammoths entered Europe around 3 million years ago; the earliest known type has been named M. rumanus, which spread across Europe and China. Only its molars are known, which show it had 8–10 enamel ridges. A population evolved 12–14 ridges and split off from and replaced the earlier type, becoming M. meridionalis. In turn, this species was replaced by the steppe mammoth, M. trogontherii, with 18–20 ridges, which evolved in East Asia ca. 1.8 million years ago. Steppe mammoth populations replaced M. meridionalis in Europe between 1 and 0.7 million years ago. The Columbian mammoth, M. columbi, evolved from a population of M. trogontherii that had entered North America over 1 million years ago. Mammoths derived from M. trogontherii evolved molars with 26 ridges between 800,000 and 400,000 years ago in Siberia, becoming the woolly mammoth, M. primigenius. The woolly mammoth would replace the steppe mammoth in Europe during the late Middle Pleistocene around 200,000 years ago. A 2011 genetic study showed that two examined specimens of the Columbian mammoth were grouped within a subclade of woolly mammoths. This suggests that the two populations interbred and produced fertile offspring. It also suggested that a North American form known as "M. jeffersonii" may be a hybrid between the two species.

By the late Pleistocene, mammoths in continental Eurasia had undergone a major transformation, including a shortening and heightening of the cranium and mandible, increase in molar hypsodonty index, increase in plate number, and thinning of dental enamel. Due to this change in physical appearance, it became customary to group European mammoths separately into distinguishable clusters:

1. Early Pleistocene – Mammuthus meridionalis
2. Middle Pleistocene – Mammuthus trogontherii
3. Late Pleistocene – Mammuthus primigenius

There is speculation as to what caused this variation within the three chronospecies. Variations in environment, climate change, and migration surely played roles in the evolutionary process of the mammoths. Take M. primigenius for example: Woolly mammoths lived in opened grassland biomes. The cool steppe-tundra of the Northern Hemisphere was the ideal place for mammoths to thrive because of the resources it supplied. With occasional warmings during the ice age, climate would change the landscape, and resources available to the mammoths altered accordingly.

In February 2021, scientists reported that DNA from million-year old mammoth remains had become the oldest ever sequenced.

Etymology and early observations

Paleolithic painting of mammoth from the Rouffignac Cave

The word mammoth was first used in Europe during the early 17th century, when referring to maimanto tusks discovered in Siberia. John Bell, who was on the Ob River in 1722, said that mammoth tusks were well known in the area. They were called "mammon's horn" and were often found in washed-out river banks. Some local people claimed to have seen a living mammoth, but they came out only at night and always disappeared under water when detected. He bought one and presented it to Hans Sloan who pronounced it an elephant's tooth.

The folklore of some native peoples of Siberia, who would routinely find mammoth bones, and sometimes frozen mammoth bodies, in eroding river banks, had various interesting explanations for these finds. Among the Khanty people of the Irtysh River basin, a belief existed that the mammoth was some kind of a water spirit. According to other Khanty, the mammoth was a creature that lived underground, burrowing its tunnels as it went, and would die if it accidentally came to the surface. The concept of the mammoth as an underground creature was known to the Chinese, who received some mammoth ivory from the Siberian natives; accordingly, the creature was known in China as yǐn shǔ 隐鼠, "the hidden rodent".

Thomas Jefferson, who famously had a keen interest in paleontology, is partially responsible for transforming the word mammoth from a noun describing the prehistoric elephant to an adjective describing anything of surprisingly large size. The first recorded use of the word as an adjective was in a description of a large wheel of cheese (the "Cheshire Mammoth Cheese") given to Jefferson in 1802.

Description

Restoration of a steppe mammoth

Like their modern relatives, mammoths were quite large. The largest known species reached heights in the region of 4 m (13.1 ft) at the shoulder and weights of up to 8 tonnes (8.8 short tons), while exceptionally large males may have exceeded 12 tonnes (13.2 short tons). However, most species of mammoth were only about as large as a modern Asian elephant (which are about 2.5 m to 3 m high at the shoulder, and rarely exceeding 5 tonnes). Both sexes bore tusks. A first, small set appeared at about the age of six months, and these were replaced at about 18 months by the permanent set. Growth of the permanent set was at a rate of about 2.5 to 15.2 cm (1 to 6 in) per year.

Size of various mammoth species compared with a human

Based on studies of their close relatives, the modern elephants, mammoths probably had a gestation period of 22 months, resulting in a single calf being born. Their social structure was probably the same as that of African and Asian elephants, with females living in herds headed by a matriarch, whilst bulls lived solitary lives or formed loose groups after sexual maturity.

Scientists discovered and studied the remains of a mammoth calf, and found that fat greatly influenced its form, and enabled it to store large amounts of nutrients necessary for survival in temperatures as low as −50 °C (−58 °F). The fat also allowed the mammoths to increase their muscle mass, allowing the mammoths to fight against enemies and live longer.

Diet

Depending on the species or race of mammoth, the diet differed somewhat depending on location, although all mammoths ate similar things. For the Columbian mammoth, M. columbi, the diet was mainly grazing. American Columbian mammoths fed primarily on cactus leaves, trees, and shrubs. These assumptions were based on mammoth feces and mammoth teeth. Mammoths, like modern day elephants, have hypsodont molars. These features also allowed mammoths to live an expansive life because of the availability of grasses and trees.

For the Mongochen mammoth, its diet consisted of herbs, grasses, larch, and shrubs, and possibly alder. These inferences were made through the observation of mammoth feces, which scientists observed contained non-arboreal pollen and moss spores.

European mammoths had a major diet of C3 carbon fixation plants. This was determined by examining the isotopic data from the European mammoth teeth.

The arctic tundra and steppe where the mammoths lived appears to have been dominated by forbs, not grass. There were richer in protein and easier to digest than grasses and wooden plants, which came to dominate the areas when the climate became wetter and warmer. This could have been a major contributor to why the arctic megafauna went extinct.

The Yamal baby mammoth Lyuba, found in 2007 in the Yamal Peninsula in Western Siberia, suggests that baby mammoths, as do modern baby elephants, ate the dung of adult animals. The evidence to show this is that the dentition (teeth) of the baby mammoth had not yet fully developed to chew grass. Furthermore, there was an abundance of ascospores of coprophilous fungi from the pollen spectrum of the baby's mother. Coprophilous fungi are fungi that grow on animal dung and disperse spores in nearby vegetation, which the baby mammoth would then consume. Spores might have gotten into its stomach while grazing for the first few times. Coprophagy may be an adaptation, serving to populate the infant's gut with the needed microbiome for digestion.

Mammoths alive in the Arctic during the Last Glacial Maximum consumed mainly forbs, such as Artemisia; graminoids were only a minor part of their diet.

Extinction

Lyuba, a mummified woolly mammoth calf, at the Field Museum of Natural History in Chicago

The woolly mammoth (M. primigenius) was the last species of the genus. Most populations of the woolly mammoth in North America and Eurasia, as well as all the Columbian mammoths (M. columbi) in North America, died out around the time of the last glacial retreat, as part of a mass extinction of megafauna in northern Eurasia and the Americas. Until recently, the last woolly mammoths were generally assumed to have vanished from Europe and southern Siberia about 12,000 years ago, but new findings show some were still present there about 10,000 years ago. Slightly later, the woolly mammoths also disappeared from continental northern Siberia. A small population survived on St. Paul Island, Alaska, up until 3750 BC, and the small mammoths of Wrangel Island survived until about 2000 BC Recent eDNA research of sediments indicates mammoths survived in north central Siberia at least as late as 2000 BC, in continental northeast Siberia until at least 5300 BC, and until at least 6600 BC in North America.

A definitive explanation for their extinction has yet to be agreed upon. The warming trend (Holocene) that occurred 12,000 years ago, accompanied by a glacial retreat and rising sea levels, has been suggested as a contributing factor. Forests replaced open woodlands and grasslands across the continent. The available habitat would have been reduced for some megafaunal species, such as the mammoth. However, such climate changes were nothing new; numerous very similar warming episodes had occurred previously within the ice age of the last several million years without producing comparable megafaunal extinctions, so climate alone is unlikely to have played a decisive role. The spread of advanced human hunters through northern Eurasia and the Americas around the time of the extinctions, however, was a new development, and thus might have contributed significantly.

Mammuthus primigenius "Hebior Mammoth specimen" bearing tool/butcher marks

Whether the general mammoth population died out for climatic reasons or due to overhunting by humans is controversial. During the transition from the Late Pleistocene epoch to the Holocene epoch, there was shrinkage of the distribution of the mammoth because progressive warming at the end of the Pleistocene epoch changed the mammoth's environment. The mammoth steppe was a periglacial landscape with rich herb and grass vegetation that disappeared along with the mammoth because of environmental changes in the climate. Mammoths had moved to isolated spots in Eurasia, where they disappeared completely. Also, it is thought that Late Paleolithic and Mesolithic human hunters might have affected the size of the last mammoth populations in Europe. There is evidence to suggest that humans did cause the mammoth extinction, although there is no definitive proof. It was found that humans living south of a mammoth steppe learned to adapt themselves to the harsher climates north of the steppe, where mammoths resided. It was concluded that if humans could survive the harsh north climate of that particular mammoth steppe then it was possible humans could hunt (and eventually extinguish) mammoths everywhere. Another hypothesis suggests mammoths fell victim to an infectious disease. A combination of climate change and hunting by humans may be a possible explanation for their extinction. Homo erectus is known to have consumed mammoth meat as early as 1.8 million years ago, though this may mean only successful scavenging, rather than actual hunting. Later humans show greater evidence for hunting mammoths; mammoth bones at a 50,000-year-old site in South Britain suggest that Neanderthals butchered the animals, while various sites in Eastern Europe dating from 15,000 to 44,000 years old suggest humans (probably Homo sapiens) built dwellings using mammoth bones (the age of some of the earlier structures suggests that Neanderthals began the practice). However, the American Institute of Biological Sciences notes that bones of dead elephants, left on the ground and subsequently trampled by other elephants, tend to bear marks resembling butchery marks, which have allegedly been misinterpreted as such by archaeologists.

Many hypotheses also seek to explain the regional extinction of mammoths in specific areas. Scientists have speculated that the mammoths of Saint Paul Island (Alaska), an isolated enclave where mammoths survived until about 8,000 years ago, died out as the island shrank by 80–90% when sea levels rose, eventually making it too small to support a viable population. Similarly, genome sequences of the Wrangel Island mammoths indicate a sharp decline in genetic diversity, though the extent to which this played a role in their extinction is still unclear. Another hypothesis, said to be the cause of mammoth extinction in Siberia, comes from the idea that many may have drowned. While traveling to the Northern River, many of these mammoths broke through the ice and drowned. This also explains bones remains in the Arctic Coast and some of the New Siberian Islands.

Dwarfing occurred with the pygmy mammoth on the outer Channel Islands of California, but at an earlier period. Those animals were very likely killed by early Paleo-Native Americans, and habitat loss caused by a rising sea level that split Santa Rosae into the outer Channel Islands.

Mammoth-elephant hybrid

Main article: Mammoth cloning

One proposed scientific use of this preserved genetic material is to recreate living mammoths. This has long been discussed theoretically but has only recently become the subject of formal effort due to advances in molecular biology techniques and cloning of mammals.

According to one research team, a mammoth cannot be recreated, but they will try to eventually grow in an "artificial womb" a hybrid elephant with some woolly mammoth traits. Comparative genomics shows that the mammoth genome matches 99% of the elephant genome, so some researchers aim to engineer an elephant with some mammoth genes that code for the external appearance and traits of a mammoth. The outcome would be an elephant-mammoth hybrid with no more than 1% mammoth genes. Other projects are working on gradually adding mammoth genes to elephant cells in vitro.