Crawling into a wolf den isn’t high on most people’s to-do list. But for researchers studying gray wolf pups in northern Minnesota, it’s key to getting good information. One day last May, a group of scientists from the Fond du Lac Band of Lake Superior Chippewa and the 1854 Treaty Authority visited two dens on tribal land near Cloquet to put radio collars on pups as part of a pilot study.

Gray wolves are highly studied animals, says Morgan Swingen, a biologist for the 1854 Treaty Authority, who entered cramped dens headfirst to capture pups that day. “But we don’t know a lot about wolf pup survival,” she says. “It’s an information gap.”

Scientists know wolves can have large litters, but many pups die before adulthood. “Knowing how many pups are coming in, and how many survive to become adults, can help us model the wolf population,” says Department of Natural Resources biologist Carolin Humpal, who helped conceive and launch the project. The 1854 Treaty Authority, an intertribal natural resource management agency, and the Fond du Lac Band are partners.

Following COVID-19 safety guidelines established by the Fond du Lac Band, researchers and their helpers found dens by tracking the movements of collared adult wolves. As humans approached, the adults fled.

At the first den on that May day, the six pups were older than expected, and they scattered. “It was a little bit of a rodeo,” says biologist Mike Schrage of the Fond du Lac Band. “Two of the pups got clean away from us. The other four we were able to capture.”

At the second den, all nine pups stayed put and were collared. When the adult wolves returned, they moved the pups to new dens—along with their fancy collars.