YOSEMITE NATIONAL PARK, Calif. - In their never-ending effort to identify Yosemite National Park's "problem bears," especially those that smash and pry their way into cars, rangers this year will start looking at a new form of evidence: DNA.
"We have blood and tissue samples from a lot of the bears," says National Park Service information officer Johanna Lombard. "And they're generally from the bears that reside in Yosemite Valley. They've been captured before, had blood drawn, had their health looked at."
Wildlife biologists trap about 30 bears a year, and those bears wear ear tags with information ranging from the location of the trap to the number of the bear's park service file - which includes blood data.
About 30 blood samples have been forwarded to a U.S. Fish and Wildlife Service laboratory in Ashland, Ore.
So when a bear leaves DNA evidence at the scene of a car break-in, he or she could get into some big trouble.
"We find that when bears break into cars, sometimes there are still shards of glass on the frame, and sometimes hair is scraped off and catches on the loose glass," Lombard says.
If the hair includes the follicle from the skin, bingo - there's some DNA to send to Ashland.
"It will help us in making decisions about bears," Lombard says.
Bears can be victims of some pretty serious decisions. Five bears, identified as habitually aggressive and destructive, were destroyed last year.
Rangers and wildlife biologists see capital punishment as a last resort, of course, and most of Yosemite's estimated 350 to 500 black bears stay out of even minor trouble. They roam through the park's 747,956 acres without causing problems.
Since 1998, when the park service launched an aggressive bear-control program that includes public education about food storage, Yosemite has seen a 59 percent decrease in "bear incidents" with humans and an 81% fall in property damage such as mangled car frames.
No new adult bears have taken up residence in developed areas for several years, according to the park service.
When they do wander into campgrounds, rangers harass them with loud noisemakers - such as firecracker pistols - or shoot them with rubber bullets.
The idea is not to harm the bears but to teach them to resist the lure of a barbecue's aroma, to avoid people and developed areas. And statistics say it's been working.