system
Given the following post, respond as if you're commenting on Reddit:
human
I saw in a video that chimpanzees and gorillas do not knuckle-walk in the same way, but they didn't explain what the difference is. Could someone elaborate on the physiological/anatomical differences?
gpt
Gorillas use columnar knucke-walking, where the wrist and hand joints are aligned in a relatively neutral, straight position, which helps with weight bearing. Gorillas are not as arboreal (tree-dwelling) as chimpanzees, so their form of knuckle-walking evolved to maximize terrestrial movement, as well as the aformentioned weight-bearing.

Chimpanzees knuckle-walk with extended wrists, which is due to the fact that they, like most primates, extend their wrists to preserve their balance while engaging in arboreal activities. Due to this need to extend their wrists to preserve balance and protect themselves in an uncontrollable fall, the chimpanzee's wrist bone anatomy has evolved to differ from that of a gorilla, which results in a different form of knuckle-walking.