A slow metabolism isn't the worst attribute after all. In fact, it's the reason humans and primates live so much longer than other living creatures, according to a study published by a varied group of distinguished researchers, Laboratory Equipment reported.
Dogs, for example, rarely make it past their teens, reproduce abundantly, and expend energy at a high rate. Humans develop slowly -- only teenagers in their teens --, rarely give birth more than 5-10 times, and conserve their energy. As a result, they, as well as primates, burn 50 percent fewer calories than animals of the same size, according to the study.
"The results were a real surprise," said Herman Pontzer, an anthropologist at Hunter College (NY) and the lead author of the study "Humans, chimpanzees, baboons and other primates expend only half the calories we'd expect for a mammal."
According to Pontzer, a "human - even someone with a very physically active lifestyle - would need to run a marathon each day just to approach the average daily energy expenditure of a mammal their size."
Does that mean elite distance runners, who are known to run up to 130 miles per week or more, are due for a shorter life span? Not necessarily. Researchers also found that zoo animals have basically the same metabolic rates as those in the wild, which are presumably more active. Thus, Pontzer's comparison isn't exactly apt if physical activity is indeed less important to metabolism and life span than previously believed.
That zoo animals and their wild counterparts are on equal metabolic footing may also be a credit to more nuanced zoo programs, according to study coauthor Steve Ross, a director at the Lincoln Park Zoo in Chicago.
"The completion of this non-invasive study of primate metabolism in zoos and sanctuaries demonstrates the depth of research potential for these settings. It also sheds light on the fact that zoo-housed primates are relatively active, with the same daily energy expenditures as wild primates," said Ross. "Dynamic accredited zoo and sanctuary environments represent an alternative to traditional laboratory-based investigations and emphasize the importance of studying animals in more naturalistic conditions."
