Experts study wolf skeletons for clues into behavior

The wolf’s skull told a painful story. Teeth were broken and missing; the jawbone infected. An injury – probably caused by a kick to the wolf’s face – had also festered.

Despite poor health, the gray wolf kept his status as alpha male of the Rose Creek pack until he died, probably of septicemia, said Sue Ware, a paleopathologist who works for Denver’s Museum of Nature and Science. A week before his death, tourists in Yellowstone National Park videoed him “hanging off the rear quarters of an elk,” Ware said.

It’s a remarkable story, said Ware, who studies the bones of Yellowstone’s wolves after they die.

“Here’s an animal – the entire front part of his face is infected. How much pain was that?” she said. Yet the wolf still managed to clamp its teeth into a fleeing elk.

Ware is about halfway through a 10-year study looking at Yellowstone wolves’ health histories and cause of death.

Wildlife research often focuses on bigger picture issues, such as wolves’ impact on deer and elk populations, or landscape level changes since wolf reintroduction. Ware’s work, however, takes a more intimate look at the predators’ lives.

Her research will help shed light on how disease and injury affect individual behavior, and ultimately, the pack.

Ware’s work underscores the risks that wolves take in pursuit of prey. Smashed skulls, missing teeth and broken ribs from elk and bison hooves are common injuries.

One wolf skull had a healed-over bite wound from a cougar attack.

“To be an alpha wolf, you either have to be successful in avoiding disease or injury, or have the fortitude to suffer through,” said Jim Halfpenny, a carnivore ecologist from Gardiner, Mont., and a collaborator in Ware’s research.

“We find a lot of bite wounds in the muzzle from pack disciplinary action,” he said.

The research is part of the Yellowstone Wolf Recovery Program through the National Park Service.

Ware’s work is forensic in nature. Yellowstone technicians look for evidence at the scene about the wolves’ cause of death when they pick up the bodies. Observations of park biologists and regular Yellowstone wolf-watchers are often invaluable for reconstructing wolves’ activities in the days before their death.

“This is the only place in the world where you can do this kind of study,” Ware said.

The dead wolves are stored in a freezer at Mammoth Hot Springs in Yellowstone until Ware can collect them. She uses Colorado State University’s laboratory space to skin and dissect animals.

Each medical exam takes four days, including photographs and drawings. Cataloging the bones takes another two weeks. So far, she’s processed 217 wolves. Twelve more are in the freezer.

While the carcasses provide important information, skeletons are Ware’s forte. She also studies the bones of dire wolves – a larger, North American wolf that went extinct about 10,000 years ago. The skeletons tell her that wolf injuries have been consistent over the centuries.

“When you go out in the morning, you’re not sure if you are going to come back, or come back in one piece,” Ware said. “If you get kicked or stomped on or gored, infection is always lurking.”

Few wolves in Yellowstone live beyond age 10. Besides the injuries from hunting, wolf-on-wolf violence is another significant cause of mortality.

After Ware’s studies are finished, the wolf skeletons are returned to the Heritage & Research Center in Gardiner, which houses the National Park Service’s collections.

Ware, a supporter of wolves’ return to Yellowstone, said she hopes her work will give people a better appreciation for predators’ dangerous and difficult lives.

“Ninety percent of people on the planet don’t have any idea of the role that carnivores play” in the ecosystem, she said.