Scientists found out how human ancestors started walking on two legs: it didn't start on land
There is a traditional assumption that our distant ancestors switched to uprightness when they moved from forest habitats to open spaces. But observations of wild chimpanzees show that it is not necessary to descend from trees to stand on two legs.
As Naked Science notes, until now, anthropologists believed that our distant ancestors' uprightness was facilitated by the need to move across the open savannah between wooded areas. In order not to become easy prey and to have a good overview, ancient primates had to move by climbing on two hind legs.
Some of our closest biological relatives still live under similar conditions. In Western Tanzania, chimpanzees from the Issa Valley inhabit small patches of forest scattered across the dry savanna. Researchers were surprised to find that these monkeys often climb on their hind legs, and it doesn't happen at all on the ground.
Researchers at the University of California, analyzed about three thousand videos of the behavior of more than 10 adult chimpanzees to find out where this action occurs - in the trees, or on the ground. The researchers assumed that because of the proximity of the plains savanna, chimpanzees would be more likely to go down to the ground, but they spent just as much time in the trees as their more wooded relatives.
Moreover, 85% of the cases of walking on two hind limbs occurred in trees when the apes were walking on branches. Therefore, it is likely that, being an exclusively arboreal species, our distant primate ancestors were walking on both feet, and the change of habitat from forests to savannah had no effect on this.
Thus, the theory that such human characteristic as uprightness did not evolve because of climate change, as chimpanzees in similar conditions do not hurry to descend from trees, but successfully walk on their hind limbs on branches. Now, in an attempt to solve this evolutionary mystery, scientists will have to make a number of additional observations of primates in different parts of the range.
Previously OBOZREVATEL reported that scientists have discovered the skull of an unknown human ancestor. Appeared relevant photofact in the network.