We may not be raring to go on a Monday morning, but humans are the Energizer Bunnies of the primate world. That's the conclusion of a new study that for the first time measures precisely how many calories humans and apes burn each day. Compared with chimpanzees and other apes, our revved-up internal engines burn calories 27% faster, according to a paper in Naturethis week. This higher metabolic rate equips us to quickly fuel energy-hungry brain cells, paving the way for our bigger brains. And lest we run out of gas when food is short, the study also found that humans are fatter than other primates, giving us energy stores to draw on in lean times.
