Fossil hands from southern Africa have provided valuable insights into the daily lives of early human ancestors. Researchers analyzed fossil hands from Australopithecus sediba and Homo naledi, dating back 2 million and 300,000 years ago respectively.
The study found that these ancient populations relied on climbing as well as handling stones for tool-related tasks. The fingers were under various stresses from climbing and other movements, leading to bone thickening in areas associated with powerful grasping. This suggests moments spent hanging on tree limbs or supporting body weight.
Advanced 3D scanning revealed the response of different parts of each finger to stress, suggesting repeated pressure from climbing. The curved shape of certain finger bones also hinted at a habit that wasn’t purely about walking or running.
Researchers found signs of bone thickening in places that would assist in pressing or gripping stones, strengthening the idea that these species were not just scanning trees for fruit. The study suggests that hand use in ancient populations didn’t transition in one straight line but instead evolved in multiple directions depending on the environment and behavior.
The powerful thumb in H. naledi caught attention, with thick bone along the thumb helping with forceful pinching or pressing against objects. Investigations of A. sediba revealed a similar pattern in the fifth digit, though less robust. This difference reminds us that individuals may have adopted separate approaches to day-to-day chores.
The study highlights how fingers can record hand use and provides insight into how these early humans adapted to their environment. The variation in cortical bone thickness across the palm and back of the fingers told researchers where pressure was being applied most often.
This research suggests that hand evolution wasn’t always linear, with some groups keeping a mix of older traits while developing improved grip for sophisticated tasks. The interplay of thickened bone for climbing and potential stone work reveals surprising layers in the story of human origins.
Source: https://www.earth.com/news/study-shows-early-humans-climbed-trees-and-worked-with-stone