Homo naledi is an extinct species of archaic human discovered in 2013 in the Rising Star Cave, Cradle of Humankind, South Africa dating to the Middle Pleistocene 335,000–236,000 years ago. The initial discovery comprises 1,550 specimens, representing 737 different elements, and at least 15 different individuals. Despite this exceptionally high number of specimens, their classification with other Homo remains unclear.
Along with similarities to contemporary Homo, they share several characteristics with the ancestral Australopithecus and early Homo as well (mosaic evolution), most notably a small cranial capacity of 465–610 cm3 (28.4–37.2 cu in), compared to 1,270–1,330 cm3 (78–81 cu in) in modern humans. They are estimated to have averaged 143.6 cm (4 ft 9 in) in height and 39.7 kg (88 lb) in weight, yielding a small encephalization quotient of 4.5. Nonetheless, H. naledi brain anatomy seems to have been similar to contemporary Homo, which could indicate comparable cognitive complexity. The persistence of small-brained humans for so long in the midst of bigger-brained contemporaries revises the previous conception that a larger brain would necessarily lead to an evolutionary advantage, and their mosaic anatomy greatly expands the known range of variation for the genus.
H. naledi anatomy indicates that, though they were capable of long-distance travel with a humanlike stride and gait, they were more arboreal than other Homo, better adapted to climbing and suspensory behaviour in trees than endurance running. Tooth anatomy suggests consumption of gritty foods covered in particulates such as dust or dirt. Though they have not been associated with stone tools or any indication of material culture, they appear to have been dextrous enough to produce and handle tools, and likely manufactured Early or Middle Stone Age industries. It has also been controversially postulated that these individuals were given funerary rites, and were carried into and placed in the chamber. In December 2022, suggestions that H. naledi used fire for light and cooking were reported.