Visitors to Jasper National Park will encounter grizzly bears from time to time and when they do there’s a good chance they’ll witness the animals digging up the roots of alpine sweetvetch.

This is a common behaviour for grizzlies, according to University of Alberta researcher Sean Coogan, especially in the spring and fall, when the plant’s roots provide an excellent source of protein for hungry bears.

“It is critical in the spring,” Coogan said. “When they come out of the dens there’s not much for them to eat.”

Coogan is nearing completion on a master’s thesis examining the nutritional value of alpine sweetvetch and the bulk of the plant samples he’s been analyzing came from just east of Jasper National Park. His work is helping scientists better understand the feeding habits of grizzly bears and could help guide future attempts to protect the threatened species’ population.

While other elements of a typical grizzly diet have been well studied, Coogan said he decided to focus on the sweetvetch root because there is “a knowledge gap” in that area and the plant is particularly important to bears in this region of Alberta.

The sweetvetch has the highest protein content and offers the most nutrition for bears in the springtime, he said, when more of the plant’s energy is stored below ground in the roots. It becomes less valuable to grizzlies in the summer when that energy is transferred into the top of the plant and its flowers. The root begins to grow in protein content again in the fall, however, as the perennial plant prepares for a long winter.

This coincides well with grizzlies’ seasonal nutritional needs and, for that reason, Coogan said you will often see the bears digging up roots as they prepare for or emerge from hibernation.

“Food really drives what they do,” he said.

It also drives their population numbers, he added, and understanding what grizzlies eat is key to understanding how many of the animals can reasonably be supported in a given environment.

Coogan, a graduate student in the U of A’s Department of Renewable Resources, spent most of his time on this project working in the lab, grinding up dozens of samples of sweetvetch root collected by others from the eastern slopes of the foothills near Cadomin. His interest in the topic, however, stems from time he spent in the field with grizzlies during two summers as an undergraduate.

“We followed around the bears and went where they went,” he said. “I always thought they were cool.”

His own, natural interest in nutrition – both human and animal – made the sweetvetch research a perfect fit for a master’s thesis, Coogan said.

He expects to finish writing the thesis in the coming weeks and is submitting his research for publication in several scientific journals.