Vestigial Traits in Humans

Our bodies teem with other remnants of primate ancestry. We have a vestigial tail: the coccyx, or the triangular end of our spine, that’s made of several fused vertebrae hanging below our pelvis. It’s what remains of the long, useful tail of our ancestors. It still has a function (some useful muscles attach to it), but remember that its vestigiality is diagnosed not by its usefulness but because it no longer has the function for which it originally evolved. Tellingly, some humans have a r...

 Hippopotamus as Closest Relative to the Whale

good candidate is the hippopotamus, which, although closely related to terrestrial mammals, is about as aquatic as a land mammal can get. (There are two species, the pygmy hippo and the “regular” hippo, whose scientific name is, appropriately, Hippopotamus amphibius.) Hippos spend most of their time submerged in tropical rivers and swamps, surveying their domain with eyes, noses, and ears that sit atop their head, all of which can be tightly closed underwater. Hippos mate in the water, an...