When they’re not making sweet love in the zoo or dodging poachers in the wild, giant pandas sit around and munch on bamboo. Their metabolic ability to take it easy has long baffled scientists.
Thanks to a study coming out of Chinese Academy of Sciences in Beijing and published in Science, we finally have some answers. For starters, giant pandas expend about 38 percent of the same energy as compared to other creatures of the same body mass. To maintain such a low metabolism, they do indeed move slowly. In the wild, pandas spend just half of their time in motion; when they forage, they average just 50 feet per hour. According to the study’s authors, that’s “very low.”
How’d they get their data? As Discovery reported:
The researchers followed five captive and three wild giant pandas (Ailuropoda melanoleuca) for about a year. By using GPS trackers and analyzing chemicals excreted in the pandas’ poop, they were able to measure the amount of energy the pandas spent each day. Surprisingly, the pandas expended only about 38 percent of the energy that an animal with the same body mass would require.
“We thought the metabolism of the panda would be low because the bamboo diet contains low energy,” said senior author Fuwen Wei, a professor of zoology at the Chinese Academy of Sciences in Beijing. “But it is very surprising that it is this exceptionally low, equal to the three-toed sloth, and much lower than the koala.”
In addition to highly evolved behavior, biology comes into play, too. Autopsies revealed low-energy wetware inside those big puffy bodies. Specifically, panda livers, kidneys and even their brains are smaller than those of other bears. This saves energy. Finally, their metabolic-managing thyroid hormones are also lower than those seen in other similarly sized mammals. According to the researchers, the levels were lower than even those in hibernating black bears.
-- Jeff Koyen