For humans, cooking played a major role in the development of smaller jaws and teeth, bigger brains, smaller guts, shorter arms, and longer legs, according to Richard Wrangham, professor of biological anthropology at Harvard University. He also believes that cooking is associated with females getting heavier and more fertile. That, in turn, changed mating and social behaviors. Instead of large males beating each other with clubs for the relatively rare privilege of mating, smaller guys mated more regularly and began to dine with the family more often. There’s a lot of agreement among anthropologists that human ancestors were cooking their food as long ago as 250,000 to 500,000 years, but Wrangham and a few of his colleagues see evidence that cooks spoiled the broth as long ago as 2 million years. That’s about the time when our ancestors became less like apes and more like humans.