Study: Orangutans Couch Potatoes of the Animal Kingdom
Posted on August 6, 2010
A study by Herman Pontzer, Ph.D., assistant professor of anthropology in Arts & Sciences at Washington University in St. Louis, has found that orangutans are the couch potatoes of the animal kingdom. Pontzer's research suggests that orangutans use less energy than even sedentary humans.
Pontzer and his team spent two weeks studying daily energy expenditure of orangutans in the Great Ape Trust, a 230-acre campus in Des Moines, Iowa. The study revealed an extremely low rate of energy use not previously observed in primates, but consistent with slow growth and low rate of reproduction in orangutans. Louis and his team have determined that orangutans living in a large indoor/outdoor habitat used less energy, relative to body mass, than nearly any eutherian mammal ever measured, including sedentary humans. All this despite activity levels similar to orangutans in the wild.
"It's like finding a sloth in your family tree," says Pontzer, "It's remarkably low energy use."
Pontzer suggests the orangutans low rate of energy use may be an evolutionary response to severe food shortages in the orangutan's native Southeast Asian rainforests. Orangutans like to eat fruit, which is sometimes scarce in the Borneo and Sumatra rainforests. The study suggests that orangutans have adapted over time by becoming consummate low-energy specialists, decreasing their daily energy needs to avoid starvation in times when food is scarce.