Australopithecus

From Wikipedia, the free encyclopedia

 

Australopithecus Temporal range: 4.5–1.977 Ma PreЄ Є O S D C P T J K Pg N ↓ Early Pliocene–Early Pleistocene
Australopithecus afarensis reconstruction, San Diego Museum of Man
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Hominidae
Subfamily:	Homininae
Tribe:	Hominini
Subtribe:	†Australopithecina
Genus:	†Australopithecus R.A. Dart, 1925
Type species
†Australopithecus africanus Dart, 1925
Subgroups
†A. africanus †A. deyiremeda †A. garhi †A. sediba Also called Praeanthropus †A. afarensis †A. anamensis †A. bahrelghazali Cladistically included genera (traditionally sometimes excluded): Paranthropus †P. aethiopicus †P. robustus †P. boisei †Kenyanthropus Homo

Australopithecus, from Latin australis, meaning 'southern', and Greek πίθηκος (pithekos), meaning 'ape', informal australopithecine or australopith (although the term australopithecine has a broader meaning as a member of the subtribe Australopithecina,  which includes this genus as well as the Paranthropus, Kenyanthropus, Ardipithecus, and Praeanthropus genera)  is a 'genus' of hominins. From paleontological and archaeological evidence, the genus Australopithecus apparently evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct two million years ago. Australopithecus is not literally extinct (in the sense of having no living descendants) as the Kenyanthropus, Paranthropus and Homo genera probably emerged as sister of a late Australopithecus species such as A. Africanus and/or A. Sediba. During that time, a number of australopithecine species emerged, including Australopithecus afarensis, A. africanus, A. anamensis, A. bahrelghazali, A. deyiremeda (proposed), A. garhi, and A. sediba.

For some hominid species of this time – A. robustus, A. boisei and A. aethiopicus – some debate exists whether they truly constitute members of the genus Australopithecus. If so, they would be considered 'robust australopiths', while the others would be 'gracile australopiths'. However, if these more robust species do constitute their own genus, they would be under the genus name Paranthropus, a genus described by Robert Broom when the first discovery was made in 1938, which makes these species P. robustus, P. boisei and P. aethiopicus.

Australopithecus species played a significant part in human evolution, the genus Homo being derived from Australopithecus at some time after three million years ago. In addition, they were the first hominids to possess certain genes, known as the duplicated SRGAP2, which increased the length and ability of neurons in the brain. One of the australopith species evolved into the genus Homo in Africa around two million years ago (e.g. Homo habilis), and eventually modern humans, H. sapiens sapiens.

In January 2019, scientists reported that Australopithecus sediba is distinct from, but shares anatomical similarities to, both the older Australopithecus africanus, and the younger Homo habilis.

Evolution

Gracile australopiths shared several traits with modern apes and humans, and were widespread throughout Eastern and Northern Africa around 3.5 million years ago. The earliest evidence of fundamentally bipedal hominids can be observed at the site of Laetoli in Tanzania. This site contains hominid footprints that are remarkably similar to those of modern humans and have been dated to as old as 3.6 million years. The footprints have generally been classified as australopith, as they are the only form of prehuman hominins known to have existed in that region at that time. 

Map of the fossil sites of the early australopithecines in Africa

 

Australopithecus anamensis, A. afarensis, and A. africanus are among the most famous of the extinct hominins. A. africanus was once considered to be ancestral to the genus Homo (in particular Homo erectus). However, fossils assigned to the genus Homo have been found that are older than A. africanus. Thus, the genus Homo either split off from the genus Australopithecus at an earlier date (the latest common ancestor being either A. afarensis or an even earlier form, possibly Kenyanthropus), or both developed from a yet possibly unknown common ancestor independently. 

According to the Chimpanzee Genome Project, the human (Ardipithecus, Australopithecus and Homo) and chimpanzee (Pan troglodytes and Pan paniscus) lineages diverged from a common ancestor about five to six million years ago, assuming a constant rate of evolution. It is theoretically more likely for evolution to happen more slowly, as opposed to more quickly, from the date suggested by a gene clock (the result of which is given as a youngest common ancestor, i.e., the latest possible date of divergence.) However, hominins discovered more recently are somewhat older than the presumed rate of evolution would suggest.

Sahelanthropus tchadensis, commonly called "Toumai", is about seven million years old and Orrorin tugenensis lived at least six million years ago. Since little is known of them, they remain controversial among scientists since the molecular clock in humans has determined that humans and chimpanzees had a genetic split at least a million years later. One theory suggests that the human and chimpanzee lineages diverged somewhat at first, then some populations interbred around one million years after diverging.

Morphology

The brains of most species of Australopithecus were roughly 35% of the size of a modern human brain. Most species of Australopithecus were diminutive and gracile, usually standing 1.2 to 1.4 m (3 ft 11 in to 4 ft 7 in) tall. In several variations is a considerable degree of sexual dimorphism, males being larger than females.

According to one scholar, A. Zihlman, Australopithecus body proportions closely resemble those of bonobos (Pan paniscus), leading evolutionary biologists such as Jeremy Griffith to suggest that bonobos may be phenotypically similar to Australopithecus. Furthermore, thermoregulatory models suggest that Australopithecus species were fully hair covered, more like chimpanzees and bonobos, and unlike humans.

Modern humans do not display the same degree of sexual dimorphism as Australopithecus appears to have. In modern populations, males are on average a mere 15% larger than females, while in Australopithecus, males could be up to 50% larger than females. New research suggests, however, that australopithecines exhibited a lesser degree of sexual dimorphism than these figures suggest, but the issue is not settled.

Species variations

Opinions differ as to whether the species A. aethiopicus, A. boisei, and A. robustus should be included within the genus Australopithecus, and no current consensus exists as to whether they should be placed in a distinct genus, Paranthropus, which is suggested to have developed from the ancestral Australopithecus line. Until the last half-decade, the majority of the scientific community included all the species shown in the box at the top of this article in a single genus. The postulated genus Paranthropus was morphologically distinct from Australopithecus, and its specialized morphology implies that its behaviour may have been quite different from that of its ancestors, although it has been suggested that the distinctive features of A. aethiopicus, A. boisei, and A. robustus may have evolved independently.

Evolutionary role

The fossil record seems to indicate that Australopithecus is the common ancestor of the distinct group of hominids now called Paranthropus (the "robust australopiths"), and most likely the genus Homo, which includes modern humans. Although the intelligence of these early hominids was likely no more sophisticated than in modern apes, the bipedal stature is the key element that distinguishes the group from previous primates, which were quadrupeds. The morphology of Australopithecus upset what scientists previously believed — namely, that strongly increased brain size had preceded bipedalism. 

If A. afarensis was the definite hominid that left the footprints at Laetoli, that strengthens the notion that A. afarensis had a small brain, but was a biped. Fossil evidence such as this makes it clear that bipedalism far predated large brains. However, it remains a matter of controversy as to how bipedalism first emerged (several concepts are still being studied). The advantages of bipedalism were that it left the hands free to grasp objects (e.g., carry food and young), and allowed the eyes to look over tall grasses for possible food sources or predators. However, many anthropologists argue that these advantages were not large enough to cause the emergence of bipedalism. 

A recent study of primate evolution and morphology noted that all apes, both modern and fossil, show skeletal adaptations to erect posture of the trunk, and that fossils such as Orrorin tugenensis indicate bipedalism around six million years ago, around the time of the split between humans and chimpanzees indicated by genetic studies. This suggested that erect, straight-legged walking originated as an adaptation to tree-dwelling. Studies of modern orangutans in Sumatra have shown that these apes use four legs when walking on large, stable branches, and swing underneath slightly smaller branches, but are bipedal and keep their legs very straight when walking on multiple flexible branches under 4 cm diameter, while also using their arms for balance and additional support. This enables them to get nearer to the edge of the tree canopy to get fruit or cross to another tree.

The ancestors of gorillas and chimpanzees are suggested to have become more specialised in climbing vertical tree trunks, using a bent hip and bent knee posture that matches the knuckle-walking posture they use for ground travel. This was due to climate changes around 11 to 12 million years ago that affected forests in East and Central Africa, so periods occurred when openings prevented travel through the tree canopy, and at these times, ancestral hominids could have adapted the erect walking behaviour for ground travel. Humans are closely related to these apes, and share features including wrist bones apparently strengthened for knuckle-walking.

However, the view that human ancestors were knuckle-walkers is now questioned since the anatomy and biomechanics of knuckle-walking in chimpanzees and gorillas are different, suggesting that this ability evolved independently after the last common ancestor with the human lineage. Further comparative analysis with other primates suggests that these wrist-bone adaptations support a palm-based tree walking.

Radical changes in morphology took place before gracile australopiths evolved; the pelvis structure and feet are very similar to modern humans. The teeth have small canines, but australopiths generally evolved a larger postcanine dentition with thicker enamel.

Most species of Australopithecus were not any more adept at tool use than modern nonhuman primates, yet modern African apes, chimpanzees, and most recently gorillas, have been known to use simple tools (i.e. cracking open nuts with stones and using long sticks to dig for termites in mounds), and chimpanzees have been observed using spears (not thrown) for hunting.

For a long time, no known stone tools were associated with A. afarensis, and paleoanthropologists commonly thought that stone artifacts only dated back to about 2.5 million years ago. However, a 2010 study suggests the hominin species ate meat by carving animal carcasses with stone implements. This finding pushes back the earliest known use of stone tools among hominins to about 3.4 million years ago.

Some have argued that A. garhi used stone tools due to a loose association of this species and butchered animal remains.

Dentition

Australopithecines have thirty two teeth, like modern humans, but with an intermediate formation; between the great apes and humans. Their molars were parallel, like those of great apes, and they had a slight pre-canine diastema. But, their canines were smaller, like modern humans, and with the teeth less interlocked than in previous hominins. In fact, in some australopithecines the canines are shaped more like incisors.

The molars of Australopithicus fit together in much the same way human's do, with low crowns and four low, rounded cusps used for crushing. They have cutting edges on the crests.

Robust australopithecines (like A. boisei and A. robustus) had larger cheek, or buccal, teeth than the smaller – or gracile – species (like A. afarensis and A. africanus). It is possible that they had more tough, fibrous plant material in their diets while the smaller species of Australopithecus had more meat. But it is also possibly due to their generally larger build requiring more food. Their larger molars do support a slightly different diet, including some hard food.

Australopithecines also had thick enamel, like those in genus Homo, while other great apes have markedly thinner enamel. One explanation for the thicker enamel is that these hominins were living more on the ground than in the trees and were foraging for tubers, nuts, and cereal grains. They would also have been eating a lot of gritty dirt with the food, which would wear at enamel, so thicker enamel would be advantageous. Or, it could simply indicate a change in diet. Robust australopithecines wore their molar surfaces down flat, unlike the more gracile species, who kept their crests, which certainly seems to suggest a different diet. The gracile Australopithecus had larger incisors, which indicates tearing and more meat in the diet, likely scavenged. The wear patterns on the tooth surfaces support a largely herbivorous diet.

When we examine the buccal microwear patterns on the teeth of A. afarensis and A. anamensis, we see that A. afarensis did not consume a lot of grasses or seeds, but rather ate fruits and leaves, but A. anamensis did eat grasses and seeds in addition to fruits and leaves.

Diet

Artistic interpretation of Australopithecus afarensis

 

In a 1979 preliminary microwear study of Australopithecus fossil teeth, anthropologist Alan Walker theorized that robust australopiths were largely frugivorous. Australopithecus species mainly ate fruit, vegetables, small lizards, and tubers. Much research has focused on a comparison between the South African species A. africanus and Paranthropus robustus. Early analyses of dental microwear in these two species showed, compared to P. robustus, A. africanus had fewer microwear features and more scratches as opposed to pits on its molar wear facets.

These observations have been interpreted as evidence that P. robustus may have fed on hard and brittle foods, such as some nuts and seeds. More recently, new analyses based on three-dimensional renderings of wear facets have confirmed earlier work, but have also suggested that P. robustus ate hard foods primarily as a fallback resource, while A. africanus ate more mechanically tough foods. A recent study looking at enamel fractures suggests A. africanus actually ate more hard foods than P. robustus, with double the frequency of antemortem chips.

In 1992, trace-element studies of the strontium/calcium ratios in robust australopith fossils suggested the possibility of animal consumption, as they did in 1994 using stable carbon isotopic analysis.

In 2005, fossils of animal bones with butchery marks dating 2.6 million years old were found at the site of Gona, Ethiopia. This implies meat consumption by at least one of three species of hominins occurring around that time: A. africanus, A. garhi, and/or P. aethiopicus.

In 2010, fossils of butchered animal bones dated 3.4 million years old were found in Ethiopia, close to regions where australopith fossils were found.

A study in 2018 found non-carious cervical lesions, caused by acid erosion, on the teeth of A. africanus suggesting the individual ate a lot of acidic fruits.

History of study

The type specimen for genus Australopithecus was discovered in 1924, in a lime quarry by workers at Taung, South Africa. The specimen was studied by the Australian anatomist Raymond Dart, who was then working at the University of the Witwatersrand in Johannesburg. The fossil skull was from a three-year-old bipedal primate that he named Australopithecus africanus. The first report was published in Nature in February 1925. Dart realised that the fossil contained a number of humanoid features, and so, he came to the conclusion that this was an early ancestor of humans. Later, Scottish paleontologist Robert Broom and Dart set about to search for more early hominin specimens, and at several sites they found more A. africanus remains, as well as fossils of a species Broom named Paranthropus (which would now be recognised as P. robustus). Initially, anthropologists were largely hostile to the idea that these discoveries were anything but apes, though this changed during the late 1940s.

The first australopithecine discovered in eastern Africa was a skull belonging to an A. boisei that was excavated in 1959 in the Olduvai Gorge in Tanzania by Mary Leakey. Since then, the Leakey family have continued to excavate the gorge, uncovering further evidence for australopithecines, as well as for Homo habilis and Homo erectus. The scientific community took 20 years to widely accept Australopithecus as a member of the family tree. 

Then, in 1997, an almost complete Australopithecus skeleton with skull was found in the Sterkfontein caves of Gauteng, South Africa. It is now called "Little Foot" and it is around 3.7 million years old. It was named Australopithecus prometheus which has since been placed within A. africanus. Other fossil remains found in the same cave in 2008 were named Australopithecus sediba, which lived 1.9 million years ago. A. africanus probably evolved into A. sediba, which some scientists think may have evolved into H. erectus, though this is heavily disputed. 

Inconsistent taxonomy

Even though Australopithecus is classified as a "genus", several other genera appear to have emerged in it: Homo, Kenyanthropus and Paranthropus. This genus is thus regarded as an entrenched paraphyletic wastebasket taxon. Resolving this into monophyletic groupings requires extensive renaming of species in the binomial nomenclature. Possibilities are to rename Homo sapiens to Australopithecus sapiens (or even Pan sapiens), or to rename all the Australopithecus species.

Notable specimens

• KT-12/H1, an A. bahrelghazali mandibular fragment, discovered 1995 in Sahara, Chad
• AL 129-1, an A. afarensis knee joint, discovered 1973 in Hadar, Ethiopia
• Karabo, a juvenile male A. sediba, discovered in South Africa
• Laetoli footprints, preserved hominin footprints in Tanzania
• Lucy, a 40%-complete skeleton of a female A. afarensis, discovered 1974 in Hadar, Ethiopia
• Selam, remains of a three-year-old A. afarensis female, discovered in Dikika, Ethiopia
• STS 5 (Mrs. Ples), the most complete skull of an A. africanus ever found in South Africa
• STS 14, remains of an A. africanus, discovered 1947 in Sterkfontein, South Africa
• STS 71, skull of an A. africanus, discovered 1947 in Sterkfontein, South Africa
• Taung Child, skull of a young A. africanus, discovered 1924 in Taung, South Africa

Louis Leakey

From Wikipedia, the free encyclopedia

 

Louis Leakey
Louis Leakey examining skulls from Olduvai Gorge
Born	Louis Seymour Bazett Leakey 7 August 1903 Kabete, British East Africa (Kenya)
Died	1 October 1972 (aged 69) London, United Kingdom
Citizenship	Kenyan, British
Known for	Pioneering the study of human evolution in Africa
Spouse(s)	Frida Avern (m. 1928; div. 1936) Mary Leakey (m. 1936)
Children	Colin Leakey Jonathan Leakey Richard Leakey Philip Leakey
Awards	Hubbard Medal (1962) Prestwich Medal (1969)
Scientific career
Fields	Archaeology, paleoanthropology, paleontology
Influenced	Dian Fossey Birutė Galdikas Jane Goodall

Louis Seymour Bazett Leakey (7 August 1903 – 1 October 1972) was a Kenyan paleoanthropologist and archaeologist whose work was important in demonstrating that humans evolved in Africa, particularly through discoveries made at Olduvai Gorge with his wife, fellow paleontologist Mary Leakey. Having established a program of palaeoanthropological inquiry in eastern Africa, he also motivated many future generations to continue this scholarly work. Several members of Leakey's family became prominent scholars themselves.

Another of Leakey's legacies stems from his role in fostering field research of primates in their natural habitats, which he saw as key to understanding human evolution. He personally chose three female researchers, Jane Goodall, Dian Fossey, and Birutė Galdikas, calling them The Trimates. Each went on to become an important scholar in the field of primatology. Leakey also encouraged and supported many other Ph.D. candidates, most notably from the University of Cambridge. Leakey also played a major role in creating organizations for future research in Africa and for protecting wildlife there.

Background

“	When I think back ... of the serval cat and a baboon that I had as pets in my childhood days—and that eventually I had to house in large cages—it makes me sad. It makes me sadder still, however, and also very angry, when I think of the innumerable adult animals and birds deliberately caught and locked up for the so-called 'pleasure' and 'education' of thoughtless human beings. ... surely there is today so many first-class films ... that the cruelty of keeping wild creatures in zoos should no longer be tolerated.	”
— Louis Leakey, By the Evidence, Chapter 4

Louis's parents, Harry (1868–1940) and Mary (May) Bazett Leakey (died 1948), were Church of England missionaries in British East Africa (now Kenya). Harry was the son of James Shirley Leakey (1824–1871), one of the eleven children of the portrait painter James Leakey. Harry Leakey was assigned to an established post of the Church Mission Society among the Kikuyu at Kabete, in the highlands north of Nairobi. The station was at that time a hut and two tents. Louis's earliest home had an earthen floor, a leaky thatched roof, rodents and insects, and no heating system except for charcoal braziers. The facilities slowly improved over time. The mission, a center of activity, set up a clinic in one of the tents, and later a girls' school. Harry was working on a translation of the Bible into the Gikuyu language. He had a distinguished career in the CMS, becoming canon of the station.

Louis had a younger brother, Douglas, and two older sisters, Gladys and Julia. Both sisters married missionaries: Gladys married Leonard Beecher, Anglican Bishop of Mombasa and then Archbishop of East Africa from 1960 to 1970; Julia married Lawrence Barham, the second Bishop of Rwanda and Burundi from 1964 to 1966; their son Ken Barham was later the Bishop of Cyangugu in Rwanda.

The Leakey household came to contain Miss Oakes (a governess), Miss Higgenbotham (another missionary), and Mariamu (a Kikuyu nurse). Louis grew up, played, and learned to hunt with the native Kikuyus. He also learned to walk with the distinctive gait of the Kikuyu and speak their language fluently, as did his siblings. He was initiated into the Kikuyu ethnic group, an event of which he never spoke, as he was sworn to secrecy.

Louis requested and was given permission to build and move into a hut, Kikuyu style, at the end of the garden. It was home to his personal collection of natural objects, such as birds' eggs and skulls. All the children developed a keen interest in and appreciation of the pristine natural surroundings in which they found themselves. They raised baby animals, later turning them over to zoos. Louis read a gift book, Days Before History, by H. R. Hall (1907), a juvenile fictional work illustrating the prehistory of Britain. He began to collect tools and was further encouraged in this activity by a role model, Arthur Loveridge, first curator (1914) of the Natural History Museum in Nairobi, predecessor of the Coryndon Museum. This interest may have predisposed him toward a career in archaeology. His father was also a role model: Canon Leakey co-founded the East Africa and Uganda Natural History Society.

Neither Harry nor May were of strong constitution. From 1904–1906 the entire family lived at May's mother's house in Reading, Berkshire, England, while Harry recovered from neurasthenia, and again in 1911–1913, while May recovered from general frailty and exhaustion. During the latter stay, Harry bought a house in Boscombe, Hampshire.

The formative years

Attendance at Cambridge

In Britain, the Leakey children attended elementary school; in Africa, they had a tutor. The family sat out World War I in Africa. When the sea lanes opened again in 1919, they returned to Boscombe, where Louis was sent to Weymouth College, a private boys' school, when he was 16 years old. In three years there, he did not do well and complained of hazing and rules that he considered an infringement on his freedom. Advised by one teacher to seek employment in a bank, he secured help from an English teacher in applying to St John's College, Cambridge. He received a scholarship for his high scores on the entrance exams. 

Louis matriculated at the University of Cambridge, his father's alma mater, in 1922, intending to become a missionary to British East Africa.

He frequently told a story about his final exams. When he had arrived in Britain, he had notified the register that he was fluent in Swahili. When he came to his finals, he asked to be examined in this language, and the authorities agreed. Then one day, he received two letters. One instructed him to report at a certain time and place for a viva voce examination in Swahili. The other asked if, at the same time and place, he would examine a candidate in Swahili.

Beginning archaeological and paleontological research

In 1922 the British had been awarded German East Africa as part of the settlement of World War I. Within the Tanganyika Territory the Germans had discovered a site rich in dinosaur fossils, Tendaguru. Louis was told by C. W. Hobley, a friend of the family, that the British Museum of Natural History was going to send a fossil-hunting expedition led by William E. Cutler to the site. Louis applied and was hired to locate the site and manage the administrative details. In 1924 they departed for Africa. They never found a complete dinosaur skeleton, and Louis was recalled from the site by Cambridge in 1925. 

Louis switched his focus to anthropology, and found a new mentor in Alfred Cort Haddon, head of the Cambridge department. In 1926, Louis graduated with a "double first", or high honours, in anthropology and archaeology. He had used some of his preexisting qualifications; for example, Kikuyu was offered and accepted as the second modern language in which he was required to be proficient, even though no one there could test him on it. The university accepted an affidavit from a Kikuyu chief signed with a thumbprint. 

From 1925 on Louis lectured and wrote on African archaeological and palaeontological topics. On graduation he was such a respected figure that Cambridge sent him to East Africa to study prehistoric African humans. He excavated dozens of sites, undertaking for the first time a systematic study of the artifacts. Some of his names for archaeological cultures are still in use; for example, the Elmenteitan.

Research fellow

St. John's College, Cambridge.

 

In 1927, Louis received a visit at a site called Gamble's Cave, near Lake Elmenteita, by two women on a holiday, one of whom was Frida Avern (1902–1993). Avern had done some course work in archaeology. Louis and Frida began a relationship, which continued upon his return to Cambridge. In 1928, they married and continued work near Lake Elmenteita. Finds from Gamble's Cave were donated by Leakey to the British Museum in 1931. At that time he discovered the Acheulean site of Kariandusi, which he excavated in 1928. 

On the strength of his work there, he obtained a post-graduate research fellowship at St. John's College and returned to Cambridge in 1929 to classify and prepare the finds from Elmenteita. His patron and mentor at Cambridge was now Arthur Keith. While cleaning two skeletons he had found, he noticed a similarity to one found in Olduvai Gorge by Professor Hans Reck, a German national, whom Louis had met in 1925 in Germany while on business for Keith. 

Olduvai Gorge

 

The geology of Olduvai was known. In 1913, Reck had extricated a skeleton from Bed II in the gorge wall. He argued that it must have the date of the bed, which was believed to be 600,000 years, in the mid-Pleistocene. Early dates for human evolution were not widely accepted by the general public at the time. Reck became involved in a media uproar. He was barred from going back to settle the question by the war and then the terms of the transfer of Tanganyika from Germany to Britain. In 1929, Louis visited Berlin to talk to the now skeptical Reck. Noting an Acheulean tool in Reck's collection of artifacts from Olduvai, he bet Reck he could find ancient stone tools at Olduvai within 24 hours.

Louis received his PhD in 1930 at the age of 27. His first child, a daughter named Priscilla Muthoni Leakey, was born in 1931. His headaches and epilepsy returned, and he was prescribed Luminal, which he took for the rest of his life.

Reversals of fortune

The Defence of Reck

In November 1931, Louis led an expedition to Olduvai whose members included Reck, whom Louis allowed to enter the gorge first. Leakey had bet Reck that Leakey would find Acheulean tools within the first 24 hours, which he did. These verified the provenance of the 1913 find, now called Olduvai Man. Non-humanoid fossils and tools were extracted from the ground in large numbers. Frida delayed joining her husband and was less enthusiastic about him on behalf of Priscilla. She did arrive eventually, however, and Louis put her to work. Frida's site became FLK, for Frida Leakey's Karongo ("gully"). 

Back in Cambridge, the skeptics were not impressed. To find supporting evidence of the antiquity of Reck's Olduvai Man, Louis returned to Africa, excavating at Kanam and Kanjera. He easily found more fossils, which he named Homo kanamensis. While he was gone, the opposition worked up some "evidence" of the intrusion of Olduvai Man into an earlier layer, evidence that seemed convincing at the time, but is missing and unverifiable now. On his return, Louis' finds were carefully examined by a committee of 26 scientists and were tentatively accepted as valid.

Scandal

With Frida's dowry money, the Leakeys bought a large brick house in Girton near Cambridge, which they named "The Close." 

Frida was now pregnant and suffered from morning sickness most of the time and was unable to work on the illustrations for Louis's second book, Adam's Ancestors. At a dinner party given in his honor after a lecture of his at the Royal Anthropological Institute, Gertrude Caton-Thompson introduced her own illustrator, the twenty-year-old Mary Nicol. Louis convinced Mary to take on the illustration of his book, and a few months later companionship turned to romance. Frida gave birth to Colin in December 1933, and the next month Louis asked her for a divorce. She would not sue for divorce until 1936.

A panel at Cambridge investigated his morals. Grants dried up, but his mother raised enough money for another expedition to Olduvai, Kanam and Kanjera, the latter two on the Winam Gulf. His previous work there was questioned by P. G. H. Boswell, whom he invited to verify the sites for himself. Arriving at Kanam and Kanjera in 1935, they found that the iron markers Louis had used to mark the sites had been removed by the Luo tribe for use as harpoons and the sites could not now be located. To make matters worse, all the photos Louis took were ruined by a light leak in the camera. After an irritating and fruitless two-month search, Boswell left for England, promising, as Louis understood it, not to publish a word until Louis returned.

Boswell immediately set out to publish as many words as he was able, beginning with a letter in Nature dated 9 March 1935, destroying Reck's and Louis's dates of the fossils and questioning Louis's competence. Despite the searches for the iron markers, Boswell averred that "the earlier expedition (of 1931–32) neither marked the localities on the ground nor recorded the sites on a map." In a field report of March 1935, Louis accused Boswell of reneging on his word, but Boswell asserted he had made no such promise, and now having public opinion on his side, warned Louis to withdraw the claim. Louis was not only forced to retract the accusation in his final field report in June 1935, but also to recant his support of Reck. Louis was through at Cambridge. Even his mentors turned on him.

On the road in Africa

Meeting Mary in Africa, he proceeded to Olduvai with a small party. Louis' parents continued to urge him to return to Frida, and would pay for everyone in the party but Mary. Mary joined him under a stigma but her skill and competence eventually won over the other participants. Louis and his associates did the groundwork for future excavation at Olduvai, uncovering dozens of sites for a broad sampling, as was his method. They were named after the excavator: SHK (Sam Howard's karongo), BK (Peter Bell's), SWK (Sam White's), MNK (Mary Nicol's). Louis and Mary conducted a temporary clinic for the Maasai, made preliminary investigations of Laetoli, and ended by studying the rock paintings at the Kisese/Cheke region.

Return to England

Steen Cottage, Nasty, Great Munden in 2011

 

Louis and Mary returned to England in 1935 without positions or any place to stay except Mary's mother's apartment. They soon leased Steen Cottage in Great Munden. This settlement was in Hertfordshire and had an unusual name which Louis, with his sense of humor noted in his Memoirs, Chapter 5, as "the village of Nasty." They lived without heat, electricity, or plumbing, fetching water from a well and writing by oil lantern. They lived in poverty for 18 months at this low point of their fortunes, visited at first only by Mary's relatives. Louis gardened for subsistence and exercise and improved the house and grounds. He appealed at last to the Royal Society, who relented with a small grant to continue work on his collection.

In British East Africa

Return to British East Africa

Louis had already involved himself in Kikuyu tribal affairs in 1928, taking a stand against female genital cutting. He got into a shouting match in Kikuyu one evening with Jomo Kenyatta, later the president of Kenya, who was lecturing on the topic. R. Copeland at Oxford recommended he apply to the Rhodes Trust for a grant to write a study of the Kikuyu and it was given late in 1936 along with a salary for two years. In January 1937 the Leakeys travelled to Kenya. Colin would not see his father for 20 years. 

Louis returned to Kiambaa near Nairobi and persuaded Senior Chief Koinange, who designated a committee of chiefs, to help him describe the Kikuyu the way they had been. Mary excavated at Waterfall Cave. She fell ill with double pneumonia and was near death for two weeks in the hospital in Nairobi, during which time her mother was sent for. Contrary to expectation, she recovered and began another excavation at Hyrax Hill and then Njoro River Cave. Louis got an extension of his grant, which he used partially for fossil-hunting. Leakey discoveries began to appear in the newspapers again. 

Tensions between the Kikuyu and the settlers increased alarmingly. Louis jumped into the fray as an exponent of the middle ground. In Kenya: Contrasts and Problems, he angered the settlers by proclaiming Kenya could never be a "white man's country."

The Fossil Police

The government offered Louis work as a policeman in intelligence, which he accepted. He traveled the country as a pedlar, reporting on the talk. When Britain went to war in September 1939 the Kenyan government drafted Louis into its African intelligence service. Apart from some bumbling around, during which he and some settlers stalked each other as possible saboteurs of the Sagana Railway Bridge, his first task was to supply and arm Ethiopian guerrillas against the Italian invaders of their country. He created a clandestine network using his childhood friends among the Kikuyu. They also hunted fossils on the sly. 

Louis conducted interrogations, analyzed handwriting, wrote radio broadcasts and took on regular police investigations. He loved a good mystery of any sort. The white leadership of the King's African Rifles used him extensively to clear up many cultural mysteries; for example, he helped an officer remove a curse he had inadvertently put on his men.

Mary continued to find and excavate sites. Jonathan Leakey was born in 1940. She worked in the Coryndon Memorial Museum (later called the National Museums of Kenya) where Louis joined her as an unpaid honorary curator in 1941. Their life was a menage of police work and archaeology. They investigated Rusinga Island and Olorgesailie. At the latter site they were assisted by a team of Italian experts recruited from the prisoners of war and paroled for the purpose.

In 1942 the Italian menace ended, but the Japanese began to reconnoiter with a view toward landing in force. Louis found himself in counter-intelligence work, which he performed with zest and imagination. Deborah was born, but died at three months. They lived in a rundown and bug infested Nairobi home, provided by the museum. Jonathan was attacked by army ants in his crib.

The turn of the tide

In 1944 Richard Leakey was born. In 1945 the family's income from police work all but vanished. By now Louis was getting plenty of job offers but he chose to stay on in Kenya as Curator of the Coryndon Museum, with an annual salary and a house, but more importantly, to continue palaeoanthropological research. 

In January 1947 Louis conducted the first Pan-African Congress of Prehistory at Nairobi. Sixty scientists from 26 countries attended, delivering papers and visiting the Leakey sites. The conference restored Louis to the scientific fold and made him a major figure in it. With the money that now poured in Louis undertook the famous expeditions of 1948 and beyond at Rusinga Island in Lake Victoria, where Mary discovered the most complete Proconsul fossil up to that time. 

Charles Watson Boise donated money for a boat to be used for transport on Lake Victoria, The Miocene Lady. Its skipper, Hassan Salimu, was later to deliver Jane Goodall to Gombe. Philip Leakey was born in 1949. In 1950, Louis was awarded an honorary doctorate by Oxford University.

Kenyan affairs

“	... I sought a personal interview with the governor, hoping to make him appreciate that it was no longer possible to continue along the lines of the old colonial regime. ... Colonial governors and senior civil servants are not easy people to argue with; and, of course, I was not popular, because of my criticism of the colonial service ... Had it been possible to make the government open its eyes to the realities of the situation, I believe that the whole miserable episode of what is frequently spoken of as 'the Mau Mau rebellion' need never have taken place.	”
— Louis Leakey, By the Evidence,Chapter 18

While the Leakeys were at Lake Victoria, the Kikuyu struck at the European settlers of the Kenyan highlands, who seemed to have the upper hand and were insisting on a "white" government of a "white" Africa. In 1949 the Kikuyu formed a secret society, the Mau Mau, which attacked settlers and especially loyalist Kikuyu. 

Louis had attempted to warn Sir Philip Mitchell, governor of the colony, that nocturnal meetings and forced oaths were not Kikuyu customs and foreboded violence, but was ignored. Now he found himself pulled away from anthropology to investigate the Mau Mau. During this period his life was threatened and a reward placed on his head. The Leakeys began to pack pistols, termed "European National Dress." The government placed him under 24-hour guard.

In 1952, after a massacre of loyal chiefs, the government arrested Jomo Kenyatta, president of the Kenya African Union. Louis was summoned to be a court interpreter, but withdrew after an accusation of mistranslation because of prejudice against the defendant. He returned on request to translate documents only. Because of lack of evidence linking Kenyatta to the Mau Mau, although convicted, he did not receive the death penalty, but was sentenced to several years of hard labor and banned from Kenya. 

The government brought in British troops and formed a home guard of 20,000 Kikuyu. During this time Louis played a difficult and contradictory role. He sided with the settlers, serving as their spokesman and intelligence officer, helping to ferret out bands of guerrillas. On the other hand, he continued to advocate for the Kikuyu in his 1954 book Defeating Mau Mau and numerous talks and articles. He recommended a multi-racial government, land reform in the highlands, a wage hike for the Kikuyu, and many other reforms, most of which were eventually adopted. 

The British realized the rebellion was being directed from urban centers, instituted military law and rounded up the committees. Following Louis' suggestion, thousands of Kikuyu were placed in re-education camps and resettled in new villages. The rebellion continued from bases under Mt. Kenya until 1956, when, deprived of its leadership and supplies, it had to disperse. The state of emergency lasted until 1960. In 1963 Kenya became independent, with Jomo Kenyatta as prime minister.

Work in Palaeoanthropology

Olduvai Gorge

“	We know from the study of evolution that, again and again, various branches of animal stock have become over-specialized, and that over-specialization has led to their extinction. Present-day Homo sapiens is in many physical respects still very unspecialized ... But in one thing man, as we know him today, is over-specialized. His brain power is very over-specialized compared to the rest of his physical make-up, and it may well be that this over-specialization will lead, just as surely, to his extinction. ... if we are to control our future, we must first understand the past better.	”
— Louis Leakey, Adam's Ancestors, 4th ed., final page

Beginning in 1951, Louis and Mary began intensive research at Olduvai Gorge. A trial trench in Bed II at BK in 1951 was followed by a more extensive excavation in 1952. They found what Louis termed an Oldowan "slaughter-house", an ancient bog where animals had been trapped and butchered. Excavations stopped in 1953 but were briefly resumed in 1955 with Jean Brown.

In 1959, excavations at Bed I were opened. While Louis was sick in camp, Mary discovered the fossilized skull OH 5 at FLK, Paranthropus boisei, famously identified as "Zinjanthropus" or "Zinj." The question was whether the fossil belonged to a previous genus discovered by Robert Broom, Paranthropus, or a member of a different genus ancestral to humans. Louis opted for Zinjanthropus, a decision opposed by Wilfrid Le Gros Clark, but one which attracted the attention of Melville Bell Grosvenor, president of the National Geographic Society. That contact resulted in an article in National Geographic and a large grant to continue work at Olduvai. 

In 1960, geophysicists Jack Evernden and Garniss Curtis dated Bed I from 1.89 to 1.75 million years ago, confirming the great antiquity of fossil hominids in Africa.

In 1960, Louis appointed Mary director of excavation at Olduvai. She brought in a staff of Kamba assistants, including Kamoya Kimeu, who later discovered many of eastern Africa's most famous fossils. At Olduvai, Mary set up Camp 5 and began work with her own staff and associates. 

At "Jonny's site", FLK-NN, Jonathan Leakey discovered two skull fragments without the Australopithecine sagittal crest, which Mary connected with Broom's and Robinson's Telanthropus. The problem with it was its contemporaneity with Zinjanthropus. When mailed photographs, Le Gros Clark retorted casually "Shades of Piltdown." Louis cabled him immediately and had some strong words at this suggestion of his incompetence. Clark apologized.

Not long afterwards, in 1960, Louis, his son Philip and Ray Pickering discovered a fossil he termed "Chellean Man", (Olduvai Hominid 9), in context with Oldowan tools. After reconstruction Louis and Mary called it "Pinhead." It was subsequently identified as Homo erectus, contemporaneous with Paranthropus at 1.4 million years old.

In 1961 Louis got a salary as well as a grant from the National Geographic Society and turned over the acting directorship of Coryndon to a subordinate. He created the Centre for Prehistory and Paleontology on the same grounds, moved his collections to it, and appointed himself director. This was his new operations center. He opened another excavation at Fort Ternan on Lake Victoria. Shortly after, Heselon discovered Kenyapithecus wickeri, named after the owner of the property. Louis promptly celebrated with George Gaylord Simpson, who happened to be present, aboard the Miocene Lady with "Leakey Safari Specials", a drink made of condensed milk and cognac. 

In 1962 Louis was visiting Olduvai when Ndibo Mbuika discovered the first tooth of Homo habilis at MNK. Louis and Mary thought it was female and named her Cinderella, or Cindy. Phillip Tobias identified Jonny's Child with it and Raymond Dart came up with the name Homo habilis at Louis' request, which Tobias translated as "handyman." It was seen as intermediary between gracile Australopithecus and Homo.

Calico Hills

In 1959 Leakey, while at the British Museum of Natural History in London, received a visit from Ruth DeEtte Simpson, an archaeologist from California. Simpson had acquired what looked like ancient scrapers from a site in the Calico Hills and showed it to Leakey. 

In 1963, Leakey obtained funds from the National Geographic Society and commenced archaeological excavations with Simpson. Excavations at the site carried out by Leakey and Simpson revealed that they had located stone artifacts which were dated 100,000 years or older, suggesting a human presence in North America much earlier than others had estimated.

The geologist Vance Haynes had made three visits to the site in 1973 and had claimed that the artifacts found by Leakey were naturally formed geofacts. According to Haynes, the geofacts were formed by stones becoming fractured in an ancient river on the site.

In her autobiography, Mary Leakey wrote that because of Louis's involvement with the Calico Hills site she had lost academic respect for him and that the Calico excavation project was "catastrophic to his professional career and was largely responsible for the parting of our ways".

The Trimates

One of Louis's greatest legacies stems from his role in fostering field research of primates in their natural habitats, which he understood as key to unraveling the mysteries of human evolution. He personally chose three female researchers, Jane Goodall, Dian Fossey, and Birute Galdikas, calling them The Trimates. Each went on to become an important scholar in the field of primatology, immersing themselves in the study of chimpanzees, gorillas, and orangutans, respectively. Leakey also encouraged and supported many other Ph.D. candidates, most notably from Cambridge University.

The last years

During his final years Louis became famous as a lecturer in the United Kingdom and United States. He did not excavate any longer, as he was crippled with arthritis, for which he had a hip replacement in 1968. He raised funds and directed his family and associates. In Kenya he was a facilitator for hundreds of scientists exploring the East African Rift system for fossils. 

In 1968, Louis refused an honorary doctorate from the University of Witwatersrand in Johannesburg, primarily because of apartheid in South Africa. Mary accepted one, and thereafter led separate professional lives.

In the last few years Louis' health began to fail more seriously. He had his first heart attacks and spent six months in the hospital. An empathy over health brought him and Dian Fossey together for a brief romance, which she broke off. Richard began to assume more and more of his father's responsibilities, which Louis resisted, but in the end was forced to accept.

Death and legacy

Death

On 1 October 1972, Louis had a heart attack in Jane Goodall's apartment in London. Jane sat up all night with him in St. Stephen's Hospital and left at 9:00 a.m. He died 30 minutes later at the age of 69. 

Mary wanted to cremate Louis and fly the ashes back to Nairobi. Richard intervened. Louis was flown home and interred at Limuru, near the graves of his parents. 

In denial, the family did not face the question of a memorial marker for a year. When Richard went to place a stone on the grave he found one already there, courtesy of Rosalie Osborn. The inscription was signed with the letters, ILYFA, "I'll love you forever always", which Rosalie used to place on her letters to him. Richard left it in place.

Prominent organizations

• 1958. Louis founded the Tigoni Primate Research Center with Cynthia Booth, on her farm north of Nairobi. Later it was the National Primate Research Center, currently the Institute of Primate Research, now in Nairobi. As the Tigoni center, it funded Leakey's Angels.
• 1961. Louis created the Centre for Prehistory and Paleontology on the same grounds as Coryndon Museum, appointing himself director.
• 1968. Louis assisted with the founding of The Leakey Foundation, to ensure the legacy of his life's work in the study of human origins. The Leakey Foundation exists today as the number-one funder of human-origins research in the United States.

Prominent family members

Louis Leakey was married to Mary Leakey, who made the noteworthy discovery of fossil footprints at Laetoli. Found preserved in volcanic ash in Tanzania, they are the earliest record of bipedal gait. 

He is also the father of paleoanthropologist Richard Leakey and the botanist Colin Leakey. Louis's cousin, Nigel Gray Leakey, was a recipient of the Victoria Cross during World War II.