An alternative hypothesis on the origin of Hominins and African Apes.

The ancestors of Humans are commonly thought to have evolved on the savannas of Africa, a theory which was originally proposed by Charles Darwin. This original proposition was based upon the fact that our closest ancestors, the African Apes, lived in the forests of Africa, and that our upright walking behaviour seemed like an adaption to open grasslands, rather than any fossil evidence available at the time. This is a plausible hypothesis, and much subsequent palaeoarchaeological evidence uncovered in Africa has appeared to support it. However, a number of recent discoveries have been hard to reconcile with this scenario, leading to the emergence of alternative ideas on Human origins.

There are a number of things about Human anatomy which appear to be inconsistent with an origin on the African Savannas. We have a furless body, a layer of subcutaneous white fat, feet much flatter than other primates, run slowly, and sweat heavily when hot or exercising, leading to the loss of fluids and minerals (our water consumption needs are high compared to other Primates even when not doing this).

For a long time it was hypothesised that knuckle-walking African forest Apes migrated onto the open grasslands, where they evolved into upright Australophithecenes, and subsequently into Humans. Over time, this theory has been modified as we have come to understand more about the environments favoured by Australopithecenes, they are now seen as inhabitants of mosaic woodlands who moved from a partially bipedal lifestyle to an obligate bipedal one to facilitate crossing more open areas, although why this should be the case remains unclear.

Another puzzle is the apparent absence of fossils ascribed to either the genera Pan (Chimpanzees) or Gorilla, despite the long lineage of fossil Human-ancestors dating back into the Pliocene. The genera Australopithecus, Paranthropus, Sahelanthropus, Orrorin, and Ardipithecus, have all been classified as Hominins, more closely related to modern Humans than either Pan or Gorilla. This is in contradiction to what would be expected, as genetic studies suggest modern Chimpanzee and Gorilla populations have diverged from large ancestral populations, while Humans apparently descend from a lineage with consistently small population sizes and repeated genetic bottlenecks. It has been suggested that this has come about because the ancestors of Chimpanzees and Gorillas lived in acidic forests, where there is lower potential for remains to become fossilised. However, this environment is more favoured by Orangutans, which do have a fossil record, than it is by Chimpanzees, which do not.

'Mrs Ples' a 2.1 million-year-old skull assigned to the species Australopithecus africanus in the collection of the Ditsong National Museum of Natural History. José Braga/Didier Descouens/Wikimedia Commons.

In a review article published in the journal Academia Biology on 10 June 2026, Marc Verhaegen of the Anthropology Study Center in Putte, Belgium, Stephen Munro of the National Museum of Australia, Kathelijne Bonne of GondwanaTalks in Madrid, Spain, Frances Mansfield, an independent researcher from Volos in Greece, and Mario Vaneechoutte of the Faculty of Medicine and Health Sciences at Ghent University, present a new hypothesis on the origins of both Humans and African Apes, in which they argue that the Australopithecenes were not, in fact the ancestors of Humans but rather of modern Gorillas and Chimpanzees. 

Verhaegen et al. not that genomic studies have found that the ancestors of modern Gorillas and Chimpanzees were infected with the Endoretroviruses PtERV1 (CERV1) and PtERV2 (CERV2) between 3 and 4 million years ago (Endoretroviruses are fragments of ancient viral DNA which have been inserted into the hosts genome), but Humans and Asian Apes show no signs of any such infections in their past. Since Humans are not immune to the effects of these Viruses, the most likely explanation is that our ancestors were geographically isolated from the epidemic. It has been suggested that Human ancestors may have moved out of Africa during much of the Miocene Epoch, when the Viruses were circulating, but Verhaegen et al. suggest that a more likely scenario is that they did not arrive in Africa at all until the Early Pleistocene. Few, if any, Animals are thought to have migrated from Africa to Europe during the Pliocene, while a range of European Animals migrated into Africa, driven by the hyper-arid climate that emerged in southern Europe at this time. 

Furthermore, Verhaegen et al. consider that the Australopithecines found in Africa during the Pliocene were not closely related to modern Humans, but rather that their smaller brains, short legs, and long arms indicate that they were related, or even ancestral, to modern African Apes. The evolution of Australopithecenes has often been seen as confusing, as earlier species often have more Human-like traits, seen as 'advanced', while later forms are often more Ape-like, or 'primitive', leading to speculation about undiscovered ghost lineages connecting earlier species to Humans. 

This distinction vanishes if Australopithecines are considered to be the ancestors of African Apes. For example, the Miocene Ardipithecus ramidus, which lived about 4.4 million years ago, had small canine teeth, similar to those seen in modern Humans, whereas the Pliocene Australopithecus africanus had much larger canines, comparable to a modern Ape. Other examples are the Miocene Orrorin tugenensis, which lived about 6 million years ago, had femurs more closely resembling those of Humans that any Pliocene Australopithecene, and the Early Pliocene Australopithecus anamensis, which lived about 4.2 million years ago, had a modified talar trochlea which would have enabled it to swing its leg forward during upright locomotion, something which is absent in subsequent members of the genus. Furthermore, later Austalopithecenes such as the Early Pleistocene Australopithecus sediba, which lived about 1.8 million years ago, appear better adapted to an arboreal lifestyle than earlier members of the group.

A cast of a skull of Ardipithecus ramidus from the Miocene of Ethiopia, in the collection of the Royal Tyrrell Museum. Chris Woodrich/Wikimedia Commons.

Other than an early adaptation to bipedalism, Verhaegen et al. see Australopithecenes as consistently more Ape-like than they are Human-like, in particular noting that Australopithecus afarensis appears more Gorilla-like and Australopithecus africanus appears more Chimpanzee-like.

Verhaegen et al. do not see Homo habilis, the smallest and earliest member of the genus Homo, which appeared in the Early Pleistocene, about 2.58 million years ago, to be a true member of the genus Homo, noting that the species shares a small brain, short leg, and long arm morphology with Australopithecenes and Apes, and in particular that the morphology of the enamel–dentine junction in this species is also more Australopithecene-like. The later, but equally small, Homo naledi is also considered to be an Australopithecene. 

In Verhaegen et al.'s view, the last common ancestor of all Australopithecenes, living Apes, and Humans, would have been an upright Miocene Ape, capable of bipedal locomotion, climbing trees, and wading in shallow water. They describe a scenario in which these Apes led a lifestyle they describe as 'aquaborealism', living in forests which were at least seasonally flooded, with a lifestyle which involved wading in waters on the forest floor, climbing trees in a vertical position, and swinging beneath branches (branchiating). From this ancestral state the Hyobatids (Gibbons and Siamangs) evolved into small, fast branchiating Apes living in the tree canopy, Orangutans into larger, slower, branchiating forms, Gorillas and Chimpanzees (separately) into knuckle-walking forms, and Humans into bipedal walkers.

They give two potential scenarios from which modern African Apes could descend from Australopithecenes; either Chimpanzees descended directly from earlier, more gracile Australopithecenes, such as Australopithecus afarensis and Australopithecus africanus, while Gorillas arose from later, more robust forms such as Paranthropus boisei and Paranthropus robustus, or they went through separate but parallel evolutionary paths, running something like Australopithecus africanus-Paranthropus robustus-Chimpanzees and Australopithecus afarensis-Paranthropus boisei-Gorillas, in response to similar environmental changes.

A skull reconstruction assigned to Paranthropus robustus in the collection of the National Natural History Museum of China. Erlend Bjørtvedt/Wikimedia Commons.

Verhaegen et al. believe that the view of the common ancestor of Apes and Humans as being Ape-like, and Apes therefore as the 'primitive' state, has distorted our view of Hominid evolution for over a century. They argue that while Australopithecenes do have some Human-like traits, these are indicators that Australopithecenes are ancestral to Humans, but rather that they share some traits derived from a mutual common ancestor that frequently adopted an upright bipedal posture as an adaptation to life in flooded forests. 

The analysis presented by Verhaegen et al. suggests two distinct phases of Human evolution associated with wet environments; an initial aquaboreal phase in flooded Miocene forests, followed by a littoral (beach dwelling) phase, which may have involved frequent shallow diving to access food, which probably continued into the Early Pleistocene.

Apes differ from Old World Monkeys in a number of ways, the most obvious of which is their much larger size. This appears likely to have been a trait found in the last common ancestor of all Apes; even the relatively small Hylobatids are thought to have evolved from a larger ancestor, due to their long gestation period, which is unusual in such a small Primate, and is thought to be a hangover from a larger ancestor. Another notable trait is the absence of a tail in Apes. This has become much reduced, and forms a part of the 'pelvic cup'; a modification of the pelvis which helps to support the intestines when in an upright position. There is no comparable tail loss in any other Primate to which this can be compared, but the idea that this was an adaptation to an upright posture while engaged in vertical climbing and branchiating seems reasonable. Furthermore, if these ancestral Apes were spending a lot of time in wading in water, then a tail might have been disadvantageous, prone to heat loss, adding to the friction of the Apes when moving through the water, and prone to infections or attacks by predators. 

Verhaegen et al. note that quadruped Animals returning to the water tend to evolve in one of two ways. Those that use spinal flexation as the main means of propulsion and the tail as the driving organ, such as Whales and Sirenians, tend to lose their hind limbs, whereas those that use their limbs for propulsion, such as Seals, Bears, Penguins, and Hippos, tend to lose their tails. An exception can be seen in Animals such as Otters and Beavers, which use their tails for propulsion but make extensive use of their limbs for foraging and movement on land. Apes, which use their limbs to swim when they enter the water, have lost their tails.

The lumbar spine of Apes is stiffer and further from their dorsal surface than is the case in most Mammals, and their forelimbs (arms) are notably long, adaptations which seems favourable to climbing in an upright position and hanging below branches. They also have wide hips compared to other Primates, and a flatter pelvis, facilitating lateral leg movements, as well as a broader sternum and thorax, which pushes their scapulas into a more dorsal position, facilitating lateral and upward arm movements. 

Fossils of Miocene Apes are often found in what have been interpreted as warm, wet, forest environments, which has led to the suggestion that they may have been aquaborreal in nature, spending their time wading through flooded forests or climbing in the branches above with their arms. Such behaviour is known in extant Apes, for example Gorillas have been observed entering forest swamps to forage for Sedges, Bonobos will wade through water to obtain Waterlilies, and Orangutans have been observed wading in shallow water in Borneo.

Bipedal Gorilla, wading. Female Gorilla with a walking stick, while crossing bipedally an Elephant pool at Mbeli Bai, Republic of Congo. Thomas Breuer & Emma Stokes in Verhaegen et al. (2011).

Verhaegen et al. propose that all modern Apes derived from this initial aquaboreal Miocene Ape, with Gibbons adopting a fast branchiating motion, Orangutans a slower branchiating movement combined with knuckle walking, Gorillas and Chimpanzees separately developing a knuckle walking gait, and the ancestors of Humans going through a distinct litoral (coast dwelling) phase.

A number of lines of evidence have pointed towards Early Pleistocene members of the genus Homo may have engaged in regular wading, swimming, and even diving. Homo erectus has been observed to have a pachyosteoscletotic skeleton (i.e. unusually dense bones), something associated with slow-moving, shallow-diving Tetrapods such as Sireneans, as well as the earliest Whales and Seals. The dense skeleton can help such Animals maintain their position in the water, particularly in saltwater environments (where the body is more buoyant). The occipital bones of Homo erectus are roughly twice as thick as those of comparably sized Apes, making the interpretation of the species as a swift bipedal predator chasing down prey hard to sustain. 

Furthermore, the low positioning of the braincase, receding forehead, absence of a chin, and forward projecting face of Homo eructus appear to be an adaptation to frequent shallow water diving, and possibly floating on their backs. The forward pointing face and paranasal sinuses of Homo eructus may indicate a habit of surfacing nose first, with the nostrils above water and the heavy occipital area at the back of the head beneath the water, something which would have worked well in a back-floating position. The basicranial flexation of modern Humans holds our face in a ventral, forward facing position. In contrast, Homo erectus would have tended to look upwards, in what would be a forward position when swimming or diving (Neanderthals are somewhere between these positions). This has been suggested to be an adaptation to foraging in coastal waters, where the easy availability of coastal food sources would compensate for the lack of stability associated with a bipedal gait on land.

Several skulls of Homo erectus have been shown to have bony growths in the inner ear called aural exotoses (or surfer's ear) which is caused by chronic exposure to cold water. This has also been observed in about half of all Neanderthals. Verhaegen et al. observe that this directly contradicts the frequent claim that there is no direct palaeontological support for the coastal Ape hypothesis.

At the same time, Human-ancestors underwent both an increase in both overall body size, and relative brain size. This is a common adaptation to moving from a terrestrial to an aquatic lifestyle, seen for example in Whales and Dolphins, but is not typical when non-aquatic Mammals increase in size; for example, the largest Apes, Gorillas, do not have relatively large brains. Homo erectus underwent a significant increase in brain size, with later specimens had a brain twice as large as that of an equivalent-sized Ape. This may have benefited from the higher proportion of nutrients such as docosahexaenoic acid, folic acid, selenium, taurine, and iodine, in aquatic-derived foods, all of which are needed for brain-growth. Such disproportionate brain growth is not seen in terrestrial carnivores, and therefore seems unlikely in a Hominin chasing prey in open grassland. Notably, Australopithicenes never showed any notable increase in brain size over their two-million-year history. Verhaegen et al. take this as evidence that early Homo did not evolve from such ancestors on the African grasslands, since there seems no good reason that our brains should have started to grow rapidly while remaining in the same environment.

There is also considerable evidence that Homo erectus did consume aquatic foods. Fossils of Homo erectus from Mojokerto on Java were found in association with numerous marine Bivalve shells, while those at Trinil on the same island, were found with the shells of  freshwater Bivalves, such as Pseudodon and Elongaria, including specimens engraved with geometric patterns. Furthermore, palaeoarchaeological remains from the Koobi Fora Formation in the Turkana Basin of northern Kenya have yielded stone tools from a Oldowan technology alongside the remains of aquatic Animals including Fish, Turtles, and even Crocodiles. Early Homo specimens from a variety of locations have dental wear associated with grit and the oral processing of marine Molluscs. Archaic members of the genus Homo are known to have reached Sulawesi by one million years ago, despite this island never being connected to the Eurasian mainland, suggesting an early ability to cross open water.

A Pseudodon shell with geometric engravings from the Trinil archaeological site in East Java, dated to about 500 000 years ago. The shell was excavated by Dutch palaeoarchaeologist Eugène Dubois in the 1880s and taken to the Netherlands. It was returned to Indonesia by the Naturalis Biodiversity Center in 2025. Naturalis Biodiversity Center/Wikimedia Commons.

The genus Homo first appeared around the beginning of the Pleistocene, with the first evidence of the consumption of aquatic foodstuffs appearing about two million years ago, across the tropical and temperate regions of the Old World. This has led to the suggestion that Homo was able to spread across this area rapidly by following coasts and rivers, wading and diving for food. There is also increasing evidence for the consumption of aquatic foods by Neanderthals across their range, as well as Modern Humans across the world, and from their earliest appearance. 

Humans differentiate from the standard morphology and physiology of Primates, and indeed terrestrial Mammals in general, in several ways. We have fleshy outward lips, a small oral opening, a closed tooth row, a more globular tongue, a descended larynx, and an external nose that still today some individuals can partially close, using nasal muscles. We also have a distinct 'Cupid's bow' to our upper lips (technically the philtrum) to our upper lips, another feature which some modern individuals can use to close their nasal airway. All of these are adaptations which enable us to regulate breathing and seal our airways better, and which may have been more pronounced in Homo erectus.

Feeding on shellfish would also have required adaptations which required improved abilities to control the sucking and swallowing of food, particularly if this was done in the water. Adaptations which improved fine control over the lips, jaw, tongue, glottis, and larynx, would also have acted as pre-adaptations for the later evolution of speech. Hunting for foodstuffs underwater, particularly if we were doing this blind (by touch alone) is also likely to have improved both our manual dexterity and the sense of touch in our fingers, something also seen in Raccoons and Otters.

In Humans, the connective tissues, tendons, ligaments, and muscles of the human foot are aligned with the hallux to form a longitudinal arch. This is unlike the foot of any other Primate, and is a good adaption to walking, and acts as a shock-absorber when running. However, it is also a particularly good adaptation to swimming, particularly as our feet are relatively larger and more paddle-shaped, and makes us particularly sure-footed on wet or infirm terrain, where other Mammals often struggle. Humans are able to swim using axial undulation, a coordinated wave of motion from trunk to hips to legs, something other Primates are unable to do. Our feet can be seen as a trade-off between something useful for swimming and something useful on land. Notably, we are less efficient runners than most other Mammals, which directly contradicts the idea that we evolved to chase large prey across grasslands.

Notably, Humans have a layer of white fat beneath our skins (the adipose layer) considerably thicker than found in any other Primate, as well as an overall fat content which is also distinctively high. In a healthy male Human, between 12% and 23% of the body mass is fat, while in a female it is between 25% and 35%. In Chimpanzees and Bonobos body fat typically makes up less than 5% of the body mass of males, and less than 8% of the bodymass of females. Thus even the leanest of Humans have a significantly higher proportion of fat than healthy Chimpanzees. This suggests that Humans have undergone a significant ecological shift after our ancestors split from those of Chimpanzees, and one which decoupled the fat content of our bodies from the its use as an energy store. Such a change is again typical of aquatic and semi-aquatic Mammals, where fat has an important role both as an insulator and as a buoyancy aid. Such a layer provides no particular role during activities such as sustained running, and may be disadvantageous, as it can hamper the dissipation of heat.

Verhaegen et al. believe that plate tectonics played an important role in the evolution of Hominoids, Hominids, and Hominins, and in particular the formation of the Red Sea and the African Rift. Until about 30 million years ago (Early Oligocene), Africa and Arabia were a single island continent, separated from Eurasia by the Tethys Ocean. Over time, this continent drifted northward, the Tethys Ocean narrowed, and a series of islands and archipelagos formed between the two continents.

Between about 30 million years ago and about 20 million years ago (during the Oligocene and Early Miocene), an episode of plume volcanism beneath the Afar Triangle led to uplift, basalt volcanism, and the formation of a triple junction rift system. The three branches of this rift would go on to form the Gulf of Aden to the east, the Red Sea to the northwest, and the Ethiopian Rift to the south. At this time Eurasia and Africa-Arabia were still separated, although the Mesopotamian Seaway, which separated Arabia from what would become Mesopotamia and Persia, was becoming increasingly narrow.

Between about 20 million years ago and about 14 million years ago (Early-Middle Miocene) the Mesopotamian Seaway slowly closed, leading to the formation of a connection called the Gomphotherium Landbridge (Gomphotherium being a type of early Elephant that migrated out of Africa across this landbridge), leading to faunal exchange between Africa-Arabia to the south and Eurasia to the north. forming the first wave of the 'Great Old World Biotic Interchange', while the Mediterranean Sea and Indian Ocean became isolated from one-another. This also led to uplift and mountain formation along the Bitlis-Zagros Suture Zone, and the development of the Dead Sea Transform and Aqaba faults in response to the added tectonic stress. At this time the Red Sea had opened, and was connected to the Mediterranean by by the Gulf of Suez, but a land bridge at Bab-al-Mandeb, connecting Arabia to Africa, separated it from the Gulf of Aden.

Between about 14 million years ago and about six million years ago (Late Miocene), movement on the Dead Sea Transform Fault, combined with the mass of sediments around the Nile Delta, closed off the connection between the Red Sea and the Mediterranean at the Gulf of Suez. Following this, the Red Sea underwent a desiccation crisis, drying up and leaving vast salt deposits, albeit with occasional marine incursions.

Between about 5.9 and 5.33 million years ago (latest Miocene), the Gulf of Gibraltar also closed, cutting off the inflow of water from the Atlantic to the Mediterranean, and triggering the Messinian Salinity Crisis, in which the Mediterranean largely dried up, leaving a vast and inhospitable salt plain. 

After about 5.33 million years ago (Pliocene), the straits of Bab-al-Mandeb opened up allowing the Red Sea to flood from the Gulf of Aden, and the Strait of Gibraltar reopened, allowing the Mediterranean to refill from the Atlantic (the Zanclean Megaflood). Around this time the Gulf of Suez reconnected to the Mediterranean, cutting off Africa from the Red Sea until the beginning of the Pleistocene, when a land bridge formed across the Sinai again.

Simplified tectonic and palaeogeographic evolution of the Mediterranean Sea and the Arabian Peninsula, with key marine connections between Africa, Arabia, and Eurasia (details of European and Paratethys geographies not given). (1) Before 30 million years ago (until the Rupelian, Oligocene); (2) 30–20 million years ago (Rupelian–Burdigalian); (3) 20–14 million years ago (Burdigalian–Langhian); (4) 14–6 million years ago; (5) From about 5.9 to 5.33 million years ago: the Strait of Gibraltar closed due to plate tectonics; (6) From 5.33 million years ago onwards. Red circle in (2): Afar plume basalt eruptions; brown line in (3): uplifting mountain front at the Bitlis-Zagros Suture Zone; red line in (3) and (4): active Dead Sea Transform Fault; pale orange in (4) and (5): desiccated marine domains; blue arrows in (6): marine gateways and direction of filling of basins. Verhaegen et al. (2026).

Verhaegen et al. suggest two alternative scenarios for the emergence of the first Apes. One scenario sees a group of Early Miocene Primates living in coastal forests and islands along the Mesopotamian Seaway, which gave rise to both the Apes and the Old World Monkeys. The other sees these ancestors living in coastal forests in East Africa, which migrated northward along the Red Sea Rift as it opened, migrating into the Arabian Peninsula and then eventually into Eurasia. This latter scenario is supported by the presence of the possible Ape Morotopithecus in Uganda about 20.6 million years ago, although the exact status of this fossil is unclear.

In either scenario, Early Apes increased in size rapidly after splitting from the Old World Monkeys, at the same time developing a very broad and strong sternum in a broad thorax, a somewhat shorter lumbar spine with only five lower and more centrally placed lumbar vertebrae (indicative of a vertical body posture), an enlarged sacrum equipped with a coccyx in a broad pelvis (cup form, supporting the intestines), external tail loss, relatively longer legs (indicative of wading), and longer arms (indicative of below-branch hanging). These early Apes are thought to have lived in (probably coastal) swamp forests, hanging beneath branches, practising aquarbourism, and developing to an upright bipedal stance. 

These early Apes probably spread along the northern coast of the Tethys Ocean, with different groups splitting off and going their own way, beginning with the Gibbons. Between 22.4 and 16 million years ago the ancestors of the Orangutans had split from those of the African Apes, moving eastward towards the coastal forests of Southeast Asia, while the proto-African Apes colonised forests along the Western Tethys (what would become the Mediterranean). 

There is a surprising absence of Ape or Hominid fossils from the Middle Miocene of Africa (between about 13 and 10 million years ago). At the same time, Eurasia has an abundance of both, particularly in southern Europe and Anatolia, with many forms looking like plausible ancestors for African Apes. Verhaegen et al. cite this as support for the idea that the ancestors of modern Humans and African Apes were not in Africa during this time, but instead in southwestern Eurasia. At this time much of southern Europe was covered by  inland seas, mega-lakes, swamps, and coastal forests, and home to Dryopithecine Apes such as Dryopithecus, Pierolapithecus, Danuvius, and Rudapithecus, which are potentially ancestral to modern Gorillas, Chimpanzees, and Humans.

A partial skull of Pierolapithecus catalaunicus, a Dryopithecine Ape from the Middle Miocene of Spain. Institut Català de Paleontologia Miquel Crusafont.

During the Vallesian Crisis (between about 11.6 and 8.7 million years ago) the climate of southern Europe became much drier and the extensive forests shrank, being replaced by open grasslands. Many of the Apes there died out, while surviving forms, such as Ouranopithecus and Graecopithecus adapted to the new environment by becoming more bipedal, and foraging in mixed woodlands and river valleys. These Apes could potentially be ancestral to later Australopithecenes and African Ape (one Turkish Ape from this period, Anadoluvius turkae, has been suggested as an offshoot from the line which led to Gorillas).

The scenario envisaged by Verhaegen et al. has a group of Dryopithecine Apes taking advantage of the closure of the Mesopotamian Sea, and migrating to the swamp forests surrounding the early Red Sea. The ancestors of Orangutans must have split from these western Apes before 14 million years ago, when the Badenian Transgression would have blocked migration between Europe and East Asia. The lineage which led to Gorillas probably split off next, migrating from Europe, where taxa such as Ouranopithecus remained, while closer ancestors such as Anadoluvius turkae migrated through Anatolia, and on to Africa, where they gave rise to Gorilla-like African Apes such as Chororapithecus and Sahelanthropus, then eventually the East African Australopithecenes and modern Gorillas.

At the same time, Graecopithecus and similar species around the Mediterranean could provide plausible ancestors for Chimpanzees and Humans, explaining the Hominid-like footprints seen at Trachilos on Crete about six millions of years ago (long before the earliest such footprints in Africa). The lineage which led to Humans and Chimpanzees must also have migrated southward, at latest during the onset of the Messinian Salinity Crisis about 5.9 million years ago, which would have made the Mediterranean Basin uninhabitable. The route from Europe into Africa across the Sinai Peninsula would have been cut off during the Zanclean Megaflood (5.33 million years ago), which filled the Mediterranean and over-spilled into the Red Sea, filling that too. The final connection between Arabia and Africa was lost about 5 million years ago, when the Bab-el-Mandeb Strait opened, connecting the Red Sea to the Gulf of Aden.

Verhaegen et al. suggest that some of these Apes crossed into Africa before 5 million years ago, giving rise to the Southern African Australopithecines and eventually modern Chimpanzees. Another group remained on the southern shore of Arabia, where they were forced to turn increasingly to the littoral environment for survival, as the land became increasingly arid and hostile.

Around 2.8 million years ago the Earth's climate cooled sharply, leading sealevels to drop abruptly. At this time early Homo migrated from Arabia into Africa and Eurasia, leading to the sudden appearance of Homo erectus across the Old World. 

A reconstruction of the skull of Homo erectus in the collection of the University of Michigan Museum of Natural History. Thomas Roche/Wikimedia Commons.

Under this scenario, the genus Homo is absent from Africa until the Early Pleistocene appearance of Homo erectus/Homo eregastor, with the Pliocene Australopithecines not being ancestral to Modern Humans, but instead relatives of Chimpanzees and Gorillas. This view is broadly in-line with several recent cladistic analyses of Human origins, which suggest African Apes and Humans are derived from Eurasian Apes, and that there were multiple crossings from Eurasia into Africa. 

Verhaegen et al. take the view that East and Southern African Australopitecines largely evolved in parallel, in response to similar ecological pressures. Thus the gracile forms, Australopithecus afarensis and Australopithecus africanus, appeared in the Pliocene, when they were able to live in forest, and in particular swamp forest, environments, whereas the more robust Early Pleistocene forms, Paranthropus boisei and Paranthropus robustus, evolved in response to cooler, drier conditions, although generally sticking close to large bodies of water, such as Papyrus swamps. Eventually the modern African Apes adopted to a life on dry forest floors.

It is possible that the Southern African Australopithecines were more omnivorous, whereas the East African forms adapted to the processing of tougher plant materials, something which is reflected in the diets of modern Chimpanzees and Gorillas. 

This later arrival of Human-ancestors into Africa provides an explanation for the absence of any trace of the Endoretroviruses PtERV1 (CERV1) and PtERV2 (CERV2) in our genomes, while the ancestors of Gorillas and Chimpanzees were affected. The potential littoral phase also explains the many morphological adaptations which set Humans apart from other Apes, as well as behavioural traits such as a fondness for water and sea coasts. 

Verhaegen et al. believe that the earliest members of the genus Homo were shelfish divers, something which would have provided them with the resources for accelerated brain growth, as well as adaptions such as an external nose and pachyosteosclerotic skeleton. As supporting evidence for this, they cite the frequent occurrence of ear exostoses (surfer's ear) in early Homo, as well as tooth wear associated with a shellfish diet, the early arrival of Homo on remote islands such as Flores and Sulawesi, and the co-occurrence of their fossils and tools with shells, and even engraved shells.

See also...

Lethal conflict during the fission of a Chimpanzee group in Kibale National Park, Uganda.

Warfare, and other forms of collective violence, are one of the more distinctive, if less pleasant, forms of Human behaviour. In these acts, Humans are able to sort themselves into groups defined by traits other than kinship, such as ethnicity, religion, language, or other cultural traits, in order to engage in conflict against other groups of Humans. It has been proposed that this is a result of our ability to use cultural traits to define cohesive social groups, giving us a distinct sense of who is 'us' and who is 'them', enabling closer cooperation with members of our group, while at the same time maintaining a hostility to outsiders. 

However, this cannot explain how conflict can erupt within formerly cohesive groups, leading to rebellions and civil wars. This has been explained by suggesting that shifting interpersonal ties and rivalries can sometimes reach a point where internal hostilities overcome the cohesion of the group, regardless of the cultural connections which have been built up. This hypothesis has some evidential support, with observations suggesting that Humans can rapidly come to regard former members of an in-group as members of an out-group for the most arbitrary of reasons. 

Non-Human Animals also engage in territorial aggression, and sometimes lethal conflict with cospecifics, despite not having the religious, cultural, or political ideologies seen in Humans. This has been observed in a variety of Animals, including Banded Mongooses, Lions, Wolves, and Primates. Non-Human Animals living in social groups also have episodes of fission, in which one group splits permanently into two or more, something which is often explained in terms of feeding competition and social pressures, although most Animal groups do not engage in lethal combat during such fission episodes.

Chimpanzees, Pan troglodytes, are among our closest relatives, and in some ways can be seen as a bridge over the gap between Human and non-Human behaviour. Male Chimpanzees stay within the group they were born in, and engage in cooperative defence of the group's territory, as well as raids on the territories of neighbouring groups. Lethal violence between males of different groups is quite common during both of these activities. This can be explained in terms of hostility towards outsiders, while remaining loyal to members of the kin group. Chimpanzee groups are known to occasionally split, a process which is thought to involve lethal violence between males familiar with one-another.

In the 1970s, a group of Chimpanzees living in the Gombe National Park in Tanzania was thought to split in two, with the males of one of the new groups subsequently killing one of the adult females and all six adult males in the other group over a period of about four years. However, this group was not under constant observation, so that much of this activity is inferred rather than having been directly witnessed, and no subsequent observations of similar splits in Chimpanzee groups were recorded in the following decades. Furthermore, a study published in 2014 which looked at the genetic structure of Chimpanzee groups suggested that such ruptures were extremely uncommon, with groups splitting on average once every 500 years.

In a paper published in the journal Science on 9 April 2026, a group of scientists led by Aaron Sandel of the Department of Anthropology at the University of Texas at Austin, present a detailed and extensively documented study of a fission event which split a group of Chimpanzees living in the Kibale National Park in Uganda, and the lethal violence associated with this split.

Sandel et al. analysed 24 years of data on the social interactions of the group, ten years of GPS data, and 30 years of demographic data on the Ngogo Chimpanzee Group, which demonstrated a three step process, in which a formerly cohesive group polarised into two clusters with little social interaction between these clusters, these clusters then actively avoided one-another for two years, before engaging in a series of lethal aggressive actions. Sandel et al. take this as evidence that Chimpanzee groups can fracture and engage in collective violence against members of the same community without any of the cultural markers seen in Humans.

The Ngogo Chimpanzees have been the subject of a continuous research project since 1995. For the first two decades of the study, they remained a single group, although they did go through a regular fission-fusion dynamic in which the larger group split into parties which changed throughout the day, though individuals frequently moved between parties and all remained within the overall territory; this is something commonly seen in Chimpanzee groups. Females typically migrated from (or to) the group at adolescence, while males born into the group remained there for life. The males formed a strict dominance hierarchy, associated in mixed-sex parties, hunted together, and cooperated in territorial patrols.

Each adult male in the group was followed for 2-3 months each year between 1998 and 2024 to see which other individuals they associated with, stayed close to, and engaged in grooming with. Despite being a single group, the Ngogo Chimpanzees typically split into two-to-four clusters over the course of a year, with two persistent and long-lived clusters, the Western and Central clusters. Membership of these clusters was fluid, with 29% of Chimpanzees switching cluster each year, and extensive ties maintained between Chimpanzees in different clusters. 

As well as clusters, Sandel et al. identified a number of 'cliques' of males that consistently stayed together, even when switching clusters. One of these cliques comprised a group of three males that would go on to form the core of the post-fission Western Group. These three males remained together consistently, even when forming clusters with males that would go on to be in the post-fission Central Group. A cluster comprising exclusively males that would go on to form the post-fission Western Group first appeared in 2014.

In 2015, Ngogo Chimpanzees at the edge of their territory hear calls from neighbouring Chimpanzees; adult males embrace each other in an act of reassurance before moving toward the calls and engaging in an intergroup encounter. 'C' and 'W' designations refer to males who would later become members of the Central and Western groups, respectively. Sandal et al. (2026).

Despite the different social clusters, all of the Ngogo Chimpanzees, including all of the males, had overlapping space use patterns, and all males shared the same set of reproductive partners. All Chimpanzees born within the Ngogo Group between 2004 and 2014 that it was possible to genetically sample had both parents from within the group, though 44% had parents from two different clusters. 

The first sign of a split between the clusters was observed on 24 June 2015, when members of the Western and Central clusters were seen to approach one-another near the centre of the territory. Unexpectedly, rather than the two groups merging as usually happened on such occasions, the Chimpanzees of the Western Cluster ran away, with the Chimpanzees of the Central Cluster chasing them. The two clusters then avoided one-another for six weeks, something which had never been observed before.

The events of 2015 precipitated the greatest change of social change seen throughout the decades-long study of the group. What had been a single large group of Chimpanzees split into a number of smaller units, stabilising as two new groups by 2018.

The first patrol by one group against another happened in 2016, when males of the Western Group, accompanied by two of the Central Group males, staged a patrol against the Central Group. All subsequent patrols by the Western males contained only members of that group. In 2017, the Central Group males staged their first patrol against the Western Group, with aggressive interactions between the two groups escalating rapidly from that point. During one encounter in 2017 the males of the Western Cluster attacked the alpha male of the Central Cluster (who had been part of the Western Cluster before 2014), severely injuring him. Both groups subsequently increased the number of patrols against the other group.

By 2017 the two groups were using largely distinct territories, with the overlap between the two groups being similar in size to that seen between unrelated groups. The centre of the shared territory had become a border. This was accompanied by reproductive isolation between the two emerging groups, with the last infant with parents from different groups being conceived in March 2015. All subsequent births had both parents from the same new group.

By 2018, the original group appeared to have split into two new groups, entirely separated from one another. At this time the Western Group included 10 males and 22 females over the age of 12, and the Central Group comprised 30 males and 39 females over the age of 12. Until 2018, a few of the females and infants from the Central Group would occasionally join the Western Group when foraging from Fig trees. After 2018 all such activity ceased.

Following this complete split, the Western Group initiated a series of lethal attacks against members of the Central Group. On all occasions members of the Central Group were attacked by multiple members of the Western Group, during a patrol by members of the Western Group into the territory of the Central Group. Six lethal attacks on males belonging to the Central Group were observed between 2018 and 2024, with a seventh attributed with a high degree of confidence. From 2021 these attacks were also carried out on infants from the Central group, with fourteen infanticides observed, and another three inferred. 

Sandal et al. note that this is a conservative estimate. Between 2021 and 2024 another 14 adult and adolescent males from the Central Group disappeared, and are thought likely to have been killed. None of these individuals showed signs of any illness when they were last observed.

In 2019, the Western Chimpanzees, including W1, W2, and W3, attack and kill the adult male Central Chimpanzee C1, who they had associated with before the fission, marking a notable shift in relationships. Sandal et al. (2026).

By using decades of data gathered on the Ngogo Chimpanzees in Kibale National Park, Sandel et al. have been able to demonstrate the occurrence of a fission event within a wild group of Chimpanzees, something predicted to happen only once every 500 years. This was followed by a series of lethal aggressive interactions, with targeted violence continuing years after the split, something not observed in any other non-Human Primate. The rate at which killings occurred was far higher than that seen in small Human societies. This demonstrates that Chimpanzees can develop new group boundaries and defend them violently, despite not having any concept of ethnicity, religion, or political ideology.

Sandal et al. speculate that a number of factors might have contributed towards the division of the Ngogo Chimpanzee Group. Firstly, the group was unusually large, with almost 200 individuals, and almost 30 males, much larger than other known Chimpanzee groups, which may have strained the males ability to maintain good relations with all other members of the group. Secondly, feeding competition has been shown to play a role in group fission in other Primate species. The area occupied by the Ngogo Group had abundant food, but the large size of the group may have caused strain at some times of the year. Thirdly, the two groups became reproductively isolated before finally separating into two groups, something which may have increased male-male aggression as they had to compete for a smaller number of mates.

Other factors which may have played a role are also observed by Sandal et al.. Firstly, six adult members of the group, five males and a female, died in 2014. The cause of these deaths is unknown, but two showed signs of illness before their deaths, making it possible that the group was hit by a disease. The loss of more than 10% of the male Chimpanzees in the group may have weakened the groups network of social relationships, leading to the group beginning to break up in 2015. 

Next, the dominant male in the group changed in 2015, immediately before the fission of the group. Such changeovers are known to raise tensions among male Chimpanzees, leading to increases in behaviours such as aggression and avoidance. The former dominant male belonged to the Central Group, whereas the new dominant male came from the Western Group, but moved to the Central Group when he ascended to the top of the hierarchy, which Sandal et al. suspect may have increased tensions between the two groups.

Finally, in January 2017, the group was hit by a respiratory epidemic which killed 25 Chimpanzees, including four adult males and ten adult females. Two of the males that died were from the Western Group, including one of the last males in that group to be maintaining relations with the Central Group. Thus, even though this event happened after the groups had started to split, it may have contributed to the final breakdown in relations between the two. 

Chimpanzees are known to have a strong sense of who is in their group, and who is not. Female Chimpanzees leave the group they were born into as adolescents and look for a new group to join, but males remain in the group they were born into their entire lives. Thus any unfamiliar male Chimpanzee is treated as a stranger, with no recorded instances of wild male Chimpanzees forming relationships or cooperating with Chimpanzees in other groups. Under these circumstances, intense hostility towards outside males appears to be an adaptive trait in male Chimpanzees, leading to potential territorial extensions for the group, which in turn leads to more food and other resources, increased female fertility, and a greater survival rate among juveniles. 

This cannot, however, explain the lethal aggression sometimes displayed to members, or former members, of the same group. During the fission of the Ngogo Group, males which had lived, fed, groomed, and patrolled together for years became targets of lethal attacks on the basis of their new group membership. This leads Sandal et al. to conclude that Chimpanzees have a sense of who belongs to their group which is based upon more than simple familiarity, and which can be updated to reflect changes in circumstances.

These results challenge previous assumptions about intergroup conflict in Chimpanzees in a number of ways. All observed attacks were initiated by the numerically smaller Western Group, which contradicts the assumption that larger groups have an advantage in such conflicts. The emergence of greater social cohesion in the smaller group appears to have given them an advantage in conflict which more than made up for the greater numbers of their opponents. These closer bonds appear to have developed before the onset of aggressive activity, suggesting that an external threat is not needed to forge these bonds. Conversely, the original Ngogo Group underwent a territorial expansion in 2009, which appears to have reduced the threat that it faced from rival groups, something which may have contributed to the long-term decline in social cohesion within the group. If this is the case, than an external threat may not be needed to forge close bonds, but it may be needed to maintain them.

Sandal et al.'s findings also have implications for Human behaviour. If Chimpanzee groups can split in this way without any of the cultural markers associated with Human conflict, then these may be less important to Humans than we generally assume, masking the actual roots of aggression, which may have more to do with interpersonal relationships. Humans tend to attribute the conflict to ethnic, religious, or political divisions, but this may be misleading, covering the actual causes of conflict. If this is the case, then  it may be in the small, daily acts of reconciliation and reunion between individuals that we find opportunities for peace.

See also...

Understanding the reasons for the use of historical anatomical skeleton collections for research in the US.

While scientists generally like to see their work as politically neutral, the nature of research carried out generally reflects the social and moral norms of the day, and these change over time. In recent years there has been an increasing discussion of the use of Human skeletal remains from historical collections in research, particularly as many such remains originally belonged to members of marginalised communities and other non-consenting individuals. A central part of this debate is whether scientists should continue to use such skeletons, and what should be done with them if it is determined that their continued use is unethical. Many such collections were amassed via processes which would be considered unethical today, such as the 'Anatomy Acts' in the US, which were passed by various state legislatures, and which allowed for the dissection and curation of unclaimed Human remains, often with a relatively short window of opportunity for the claiming of remains. This disproportionately affected poor and marginalised communities, who were often unable to afford to claim and bury the remains of their relatives within the short time available. 

In a paper published in the American Journal of Biological Anthropology on 27 March 2026, Allyson Simon and Nicholas Passalacqua of the Department of Anthropology at The Ohio State University, and Mark Hubbe of the Department of Anthropology at the University of Tennessee, present a review of research which has used Human remains from four Historical Anthropological Skeletal Collections, with a view to understanding current and past standards and social values in biological anthropology.

The use of historical anthropological skeletal collections has played a key role in the field of biological anthropology, with techniques such as the methods for estimating sex, age, stature, and population affinity, having first been developed using material from such collections. Despite this, until relatively recently little-or-no consideration was given to the lived experiences of the people whose remains found their way into such collections, or of the circumstances under which they got there. Today, there are ongoing discussions about the continued use and curation of these skeletons, with some scholars calling for such collections to be permanently dismantled and the remains held in them buried or cremated, while others argue that these are still vital resources that it will not be possible to replace once they are gone, and that they should therefore continue to be preserved.

Historical anatomical skeleton collections often include records of individuals' names, sex, age, cause of death, and other identifying information, presenting a unique set of ethical considerations. Because of this, Simon et al. felt it was important to distinguish between collections where such information has been preserved and those where it has not. They note that some previous ethical studies have lumped the two types of collections together, thereby ignoring some nuanced differences in both the demographics of these collections, and the way in which they are used by researchers. They further note that the views of both the scientific and non-scientific communities should be taken into account when determining the potential benefits of any research involving such collections.

Understanding how Human remains in historical collections have been used by researchers in the past, as well as how they are used today is an important step in evaluating the ethical dilemmas relating to these collections. When skeletons have been used in the development and validation of osteological methods without any consideration of the lived experiences of those individuals, there is a danger of those individuals being reduced to their value as osteological specimens, with their lives and individual identities being lost. It has also been noted that the value of studies based upon such collections might be lower than expected, as the way in which collections acquired skeletons makes the collections unrepresentative of the wider population. However, few previous studies have asked whether those methodological studies are ethically appropriate. Anthropological studies, in contrast, focus primarily on the lifetime experiences of the individuals involved, and often engage with current social theory. While such studies cannot undo past injustices, they do tend to re-emphasise the fact that the remains involved were once living people.

Understanding the aims of research is an important way of understanding the communities which that research serves, and can act as a proxy for the social perspective of the researchers. The Ghent Phrenological Collection comprised about 200 skulls transferred from the prison in Ghent, Belgium, to the University Museum in the same city in 1845. For the next century it was used as both a teaching aid and a research tool. However, much of the research for which the skulls were used was concentrated on the now discredited fields of eugenics and racial science, and some of that research was used to justify the atrocities of the Holocaust. Because of this the collection was felt to have become tainted by association, and following the Second World War the decision was taken to cremate the remains. However, it has been suggested that this could be seen as another act of violence against the people whose remains were held in the collection, as the method of disposal was chosen without reference to their wishes or the cultural norms of the societies which produced them.

Simon et al. believe that the debate around the continuing use of human remains from historical collections should be informed by accurate information on the uses to which they are put by researchers. To this end, they reviewed articles published in academic journals between 1920 and 2024, and the abstracts of presentations from the annual conferences of the American Association of Biological Anthropologists and the American Academy of Forensic Sciences between 2014 and 2024, which referenced samples from four historical anthropological collections, the Hamann-Todd Human Osteological Collection held by the Cleveland Museum of Natural History, the Robert J. Terry Anatomical Skeletal Collection held by the Department of Anthropology at the Smithsonian National Museum of Natural History, the W. Montague Cobb Human Skeletal Collection held by Howard University, and the George S. Huntington Anatomical Collection, also held by the Smithsonian Museum.

Deathmask, skull, and cadaver photograph of number 709 from the Robert J. Terry Anatomical Collection. Hunt & Albanese (2004).

These publications were analysed to determine the aims of the research being carried out in each case, with the studies being divided into five categories, 'anthropological' research, which sought to understand past human lives and experiences, often shaped by social theory, 'comparative' studies, in which specimens from one or more of the collections were compared to another sample in order to make an assessment of that sample, 'methodological' studies, concerned with the development, validation, and refinement of osteological methods and procedures for data collection and analysis, 'clinical' studies which aimed to contribute to medical knowledge and clinical practice, and 'other' studies, where the aims of the research could not be fit into one of the other categories, or could not be determined at all. These categories were not exclusive, in some cases studies were placed into more than one category.

Based upon this, Simon et al. attempted to answer four questions, (1) whether research with methodological aims was becoming less common, (2) whether work with anthropological aims was becoming more common, (3) whether different forms of research were rewarded better in terms of citations by other authors, and (4) how the preponderance of different types of research varied across journals.

The Hamann-Todd Human Osteological Collection and the Robert J. Terry Anatomical Skeletal Collection were the most commonly used in both journal articles and conference abstracts. Twelve percent of journal articles used samples from more than one of the studied collections, while 32% used samples from at least one of the studied collections, plus samples from another collection, with the most commonly cited being the Knoxville Donated Skeletal Collection at the University of Tennessee. 

Collection usage based upon (a) journal articles, (b) American Association of Biological Anthropologists conference abstracts, and (c) American Academy of Forensic Sciences conference abstracts. Simon et al. (2026).

The majority of both research papers and conference abstracts had methodological aims. Anthropological aims were most common in the American Association of Biological Anthropologists conference abstracts, but almost absent from the American Academy of Forensic Sciences conference abstracts. 

The oldest journal article was from 1920, and was a paper by Thomas Wingate Todd discussing ageing of the pubic symphysis in individuals in the Hamman-Todd Collection.

Ossa innominata of specimen 571, male, white, age sixty-nine. An illustration from Thomas Wingate Todd's 1920 paper Age changes in the pubic bone. I. The male white pubis. At the time Todd was an advocate of the theory of racial determinism, which held that education and environment were less important than heredity in development, but in later life came to reject these ideas. Todd (1920).

Methodological aims became less common over the 124 years of the study, but still represent the largest category, representing 69% of all journal articles. The number of research articles using historical anatomical skeletons has been increasing over the past decade. The number of anthropological studies has increased over the total time-frame, but still makes up only 14% of the total. Thirteen studies from journals were placed into more than one category, but in only three of these was anthropology one of those categories. Eighty one percent of the journal articles were hypothesis-driven research. Only three of the journal articles were review studies or meta-analyses.

Total count of journal articles with each research aim category between 2014 and 2024. Some journal articles are counted more than once due to having more than one research aim. Simon et al. (2026). 

Slightly over half of the American Association of Biological Anthropologists conference abstracts had methodological research aims, while 36% had anthropological aims. Six of these abstracts had both methodological and anthropological aims. In the American Academy of Forensic Sciences conference abstracts, 98.3% had methodological aims, while one had an anthropological aim and one had both an anthropological and a methodological aim. Almost all of the conference abstracts related to hypothesis-driven research, there were no review papers or meta analyses. The most common subject of the methodological research was sex determination, comprising 39.1% of the American Association of Biological Anthropologists conference abstracts and 50.9% of the American Academy of Forensic Sciences conference abstracts. This was followed by age determination, which made up 23.4% of the American Association of Biological Anthropologists conference abstracts and 33.3% of the American Academy of Forensic Sciences conference abstracts.

Frequency of methodological and anthropological research aims from journal articles between (a) 1975 and 2024, and (b) 2014 and 2024. Simon et al. (2026).

The number of American Association of Biological Anthropologists conference abstracts fluctuated considerably from year-to-year over the course of the studied period, but there has been no evidence of any decline in the number of methodological samples. There did appear to be an increase in the number of anthropological studies over the time period, although the variation in the number of anthropological studies over the entire period was less than the year-to-year variation in the number of methodological studies.

Total count of American Association of Biological Anthropologists abstracts with each research aim category between 2014 and 2024. Some abstracts are counted more than once due to having more than one research aim. Simon et al. (2026).

Due to the overwhelming preponderance of Methodology driven research in the American Academy of Forensic Sciences conference abstracts, no statistical analysis of this data was attempted. However, Simon et al. did note that there the number of studies using specimens from historical anatomical collections did decline over time.

Frequency of American Academy of Forensic Sciences abstracts that address methodological research aims with a historical anatomical skeleton collection sample between 2014 and 2024. Simon et al. (2026).

Of the ten most cited journal articles in the study, eight were methodology-based, while two fell in the 'other' category, one of these having addressed the subject of secular change in bone length, and the other the demographics of the skeletons in the Robert J. Terry Anatomical Collection. These most referenced papers were typically studies which had introduced methods which had become widely used, with six of the eight written before 2000.

Simon et al. also looked at what sort of journals tended to publish articles containing data from historical anatomical skeleton collections, concluding that the majority of such articles were published in forensic anthropology journals.

Simon et al. note an overall decline in the use of historical anatomical skeleton collections in research, along with a declining number of methodology-related studies, which have previously been the greatest users of such collections. The number of anthropological studies of material from historic collections was observed, but only in the American Association of Biological Anthropologists conference abstracts. Simon et al. propose two possible explanations for these results, either a declining usefulness for historical specimens within forensic anthropology, or a cultural shift away from studying the remains of marginalised individuals without there consent. 

Much of the development of the science of forensic anthropology has come about through the use of remains from historical collections. However, in recent years, collections made up of donated skeletons have become increasingly available. At the same time, studies of secular changes in skeletal changes have shown that these historical collections are less scientifically useful for understanding modern populations. This decline in the use of historical collections for forensic purposes has not been accompanied by an equivalent increase in anthropological studies, probably because this lies outside the traditional goals of the science.

The ongoing discussion about the ethics of using human material that was not voluntarily surrendered appears to have driven a shift in the way they are used in research. As such collections have become less useful for forensic studies, it has also become clear that they are able to provide useful information about the lives of historically marginalised communities. This creates a moral dilemma which scientists are now beginning to address, and which will probably result in the development of new ethical codes for the use of such material.

See also...