Then, in 1959, came the now-famous discovery, in Olduvai, of a 1.75-millionyear-old skull that Leakey named Zinjanthropus boisei ... heavier bones and bigger teeth. Nearly three decades of ...

Why do humans have canine teeth? Patrick McGannon, Surprise, Arizona All primate species have them, says Sabrina Sholts, a curator of physical anthropology at the Museum of Natural History.