The third molars—the last of a group of teeth that grinds food into easy-to-swallow chunks—tend to be overcrowded in adult human mouths, and thus require yanking. But every other toothed mammal has room for their “wisdom teeth,” and so did Neanderthals and other early hominids, says evolutionary biologist Leslea Hlusko of the University of California, Berkeley. So why have those teeth become such a pain for us?