Our primate ancestors started walking upright about 4.4 million years ago. Researchers from the UK found that this happened while they were still living on trees, in order to balance themselves and have a broader reach to fruit. Chimpanzees use upright walking on trees, and spend more time there than on the ground, which is what made the researchers look in that direction and explore it.
Photo by: https://pixabay.com/photos/chimpanzee-ape-feed-catch-wildlife-3741278/
