Garbage putting bears at greater risk of death, experts say

SOUTH LAKE TAHOE, Calif. -- The habitat of Lake Tahoe bears is not defined by their once-expansive range high in the snowy Sierra Nevada mountains or surrounding pine forests. Here, the black bear's domain can be measured in city blocks.

A year-round supply of garbage has lured the beasts to the streets that ring this resort area.

In settling into the easy life, the Tahoe bear has altered its hibernation cycle, taken to prowling the graveyard shift and grown fatter than your average bear.

The consequences can be deadly for the bears, according to a study in the Journal of Zoology that documents behavioral changes as the bears have adapted to a human environment.

The study by Jon Beckmann and Joel Berger of the Wildlife Conservation Society debunked assumptions that the bear population was booming.

Instead, it found bears were moving from the mountains to neighborhoods, highlighting a growing problem across North America as housing creeps into wildlands and animals take advantage.

More bears are being hit by cars as they hunt for food closer to cities. And when they bust into houses, wildlife officials will often kill them to protect public safety.

Historically, black bears in the Tahoe basin roamed up to 150 square miles and weighed 200 to 300 pounds, said Carl Lackey, a wildlife biologist with the Nevada Department of Wildlife who helped with the study.

Not anymore.

"At one point we had 12 bears within one square mile of a Dumpster," Lackey said. "Good ol' Burger King. Those Whoppers fed some whopper bears. We had several in the 450- to 550-pound range."

For an animal with a 25,000-calorie-a-day diet, Dumpster diving is the fastest food available. The bears get their fill in a few hours by covering little ground compared with their wilder counterparts that spend more than 20 hours a day foraging for berries, nuts and carrion.

Most bears retreat into dens for the winter because of dwindling food supplies. The urban bears, however, have a steady supply of vittles, leading to shorter hibernation periods. Five of the 38 bears studied around Tahoe didn't even take their winter naps.

"They come out once a week -- garbage night," Lackey said.