A team of researchers from Hunter College found that humans and other primates burn 50% fewer calories each day than other mammals. But here’s the plus side, our slower metabolisms could explain why we mature slowly and live longer lives. They studied a variety of primates in zoos and in the wild monitoring the body’s production of carbon dioxide to come to their findings. On an interesting note, those primates in the wild didn’t really burn more calories than the ones in the zoos suggesting the physical exertion could have less of an impact on daily energy expenditure than previously believed. Researchers said that the higher caloric expenditure of our four legged friends contributes to the aging process and that’s why they have shorter lives.