Giant panda bears have the stomachs of lions, yet manage to subsist on a diet consisting of almost entirely bamboo. Bamboo has little nutritional value and pandas must eat as much as 22 to 44 pounds of it per day. Scientists have discovered that this may be possible because pandas have extremely slow metabolic rate and small organs.

In a recent study, scientists have found that the metabolic rate of a panda bear is substantially lower than almost all other mammals. Most of the energy bodies use is sucked up by only a few organs - brain, kidneys, heart, and liver. But pandas have very small organs for their body size, meaning their bodies don't necessarily need a lot of energy to sustain them.

Plus, they are very inactive: GPS loggers tracked wild pandas and showed they moved on average at just 88.3 feet per hour on average. They're so slow they couldn't kill meat if they tried.

Cover image: Flickr