How We Determine What Food Fueled Human Evolution

Humans can and do eat anything and everything.  If we cannot eat it directly, we give it to an organism (from yeast to cattle) to eat it for us by transforming it into something that we can eat such as beer, bread, and meat.  Humans are also unique within the primate order because most human populations eat meat across all ecological zones inhabited by humans.  In contrast, other nonhuman primates, e.g., capuchins, baboons, and chimpanzees, eat meat under restricted conditions and in limited areas.  Today, we can determine the caloric, protein, micronutrient, and social benefits of eating meat; but the identification of meat eating in the human fossil record is not an easy task.  Often, there are no accompanying cultural items that signal meat-eating.  Stone tools can be used for other tasks than cutting meat or pounding bones, and may carry no identifying scratch marks.  Therefore, isotopic evidence has become a critical source of data signaling that meat is included in the diet of our fossil relatives.  Here I present those data and discuss the constraints surrounding their interpretations.