At a Glance

Researchers followednine polar bears over a three-year period.Five of the nine bears studied lost body mass, indicating they were unable to catchenoughprey to meet their energy demands.Retreating ice sheets,a result of climate change, are forcing the bears to travel greater distances to find the food they need.

Polar bears may face extinction sooner than anticipated because they may not be able to find enough food to sustain them, a new study says.

A study by the U.S. Geological Survey and the University of California Santa Cruz Thursday found that polar bears have a higher metabolism than previously thought and are having trouble finding enough food to meet their energy needs as climate change alters their environment.

over a three-year period and found that an adult polar bear requires at least one adult seal or three juveniles every 10 days to sustain itself, according to a USGSpress release.

Five of the nine bears studied lost body mass, indicating they were unable to catchenoughprey to meet their energy demands.

"We've been documenting declines in polar bear survival rates, body condition, and population numbers over the past decade," said lead author Anthony Pagano, a Ph.D. candidate at UC Santa Cruz andwildlife biologist with USGS. "This study identifies the mechanisms that are driving those declines by looking at the actual energy needs of polar bears and how often they're able to catch seals."

Pagano noted that this observation was made during "the period from April through July when polar bears catch most of their prey and put on most of the body fat they need to sustain them throughout the year."

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Retreating ice sheets, a result of climate change,are forcing the bears to travel greater distances to find the food they need, which in turn causes them to expend more energy than in the past, the study said.

"We found that polar bears actually have much higher energy demands than predicted. They need to be catching a lot of seals," Pagano said.

USGS researchers have been studying polar bears in the Beaufort Sea area since the 1980s and have found that polar bear populationhas declined by 40 percent in the past decade. The remote location has made it difficult for scientists to study the bears' movement and activities until now.

"We now have the technology to learn how they are moving on the ice, their activity patterns, and their energy needs, so we can better understand the implications of these changes we are seeing in the sea ice," Pagano said.