A hibernating bear might appear to be the perfect metaphor for laziness, laying around half the year in carefree slumber. But in fact, it is a marvel of efficiency. New research in the journal Science shows that bears can drop their metabolic rate all the way down to 25 percent of normal while losing only about 10 degrees in body temperature.

Øivind Tøien and colleagues got lucky when a few black bears came a little too close to residents of Alaska for the Alaskans’ comfort. The state’s Department of Fish and Game intended to remove them as a “nuisance,” so the researchers got their hands on the bears and did a little hibernation experiment. They built artificial dens for the large mammals, complete with cameras and observational equipment including radio transmitters, allowing them to track the bears’ body temperatures and other vitals.

It was thought that, like most animals, the bears would have to drop their body temperatures to put the brakes on metabolism—each 18-degree Fahrenheit (10-degree Celsius) drop in temperature should equal a 50-percent reduction in the chemical activity. [National Geographic]

The ...