Friday, October 28, 2011
Researcher's study of bones shows Yellowstone wolves' grit
BILLINGS - Despite loose and missing teeth, disease and an injury from being kicked by an elk, at 7 years old wolf No. 8M was still hunting elk in Yellowstone National Park as the alpha male of the Rose Creek pack.
The animal's determination and grit impressed Sue Ware, a paleopathologist who works for the Denver Museum and has been studying bones of the park's wolves, including 8M, since 2008.
"I don't understand how an animal could live through this," she said.
After his death, Ware's examination of 8M's skeleton showed his muzzle to be riddled with holes from a bone infection, his canine teeth were loose and blunted. The infection probably led to his death, since it can cause heart disease, organ damage and severe pain.
Yet a week before he died, wolf watchers had shot a video of the male hanging onto an elk during a hunt - loose, dull teeth and all.
"He was never challenged for his position in the pack, and he was doing everything you would expect him to do in the pack," she said.
Ware's analysis of about 160 wolf skeletons over the past three years has revealed more details on just how tough it is in the wild canid's world. Her examination of their bones has revealed injuries from attack by other wolves, a cougar bite to one wolf's skull, assorted broken ribs and legs from kicks by elk and bison, as well as broken foot bones.
"One of the things that is most detrimental is reinjury," Ware said. "I see a lot of reinjured bones."
The reinjuries occur because, unlike an injured human athlete, the wolves can't sit out of the wild games until they are healed. They have to soldier on.
To make her examinations, Ware has to first have the carcasses cleaned of all tissue. Then she examines each of the wolves' 320 bones (321 for males). To determine what animal may have caused a bite injury - another wolf, bear or cougar - she measures the incision and compares it to the tooth size and shape of the other predators.
It's a painstaking task, one that she's used to study wolves from the upper Midwest, Canada and Alaska, as well as the fossilized remains of dire wolves - a large-headed relative of the gray wolf that went extinct in North America about 9,500 years ago.
Compared to wolf bones she has examined from other areas, Ware said the Yellowstone animals tend to be healthier. Yet those with injuries, some of them quite severe, demonstrate how tough the animals can be and provide the most interesting tales.
Take wolf No. 21M, an alpha male for the Druid Pack. He lived to be 9 years old, despite an injury to the top of his skull and cracked and worn teeth. Wolf No. 483F of the Leopold and Geode Creek packs suffered two different attacks that scarred the top of her skull - one likely from another wolf, and another probably from a female cougar. Although she survived those attacks for a while, she later died from a brain infection likely caused from the injuries.
"One good thing about the research that I'm doing is that it provides another lens for looking at these wolves," Ware said. "It gives other researchers a little more information on each and every one of these guys. It's a pretty interesting story all around."