Add Yahoo as a preferred source to see more of our stories on Google. Mammals descend trees in different ways, and primates stand apart. (CREDIT: Andrew Mercer / Wikimedia Commons / CC BY-SA 4.0) A ...

A monkey descending a tree trunk often keeps its head up, moving almost like a cautious climber backing down a ladder. Squirrels and many other mammals, by contrast, tend to go headfirst. That ...