A female wolf that crossed from Isle Royale National Park to Grand Portage National Monument via an ice bridge across Lake Superior was killed by a pellet gun wound, according to veterinarians.

The wolf's carcass was found on the shore of the national monument on February 8. It had been fitted with a radio collar as part of a long-term study conducted by the National Park Service and Michigan Technological University in Houghton, Michigan.

"Wolf movement to and from Isle Royale National Park across ice 'bridges' during extremely cold winters has occurred historically, but is not common," Isle Royale Superintendent Phyllis Green said Friday in a press release. "The studies at Isle Royale have helped us know these wolves on an individual level, and this is the first insight we've had into travels of a wolf after leaving the island. This year, several ice bridges formed, and the natural movement of this lone wolf from Isle Royale is not surprising."

A necropsy on the wolf's body showed that a pellet had pierced the animal's rib cage and led to its death. The necropsy was conducted by pathologists at Colorado State Veterinary Diagnostic Laboratory in cooperation with National Park Service veterinarians. The remains are to be returned to Michigan Tech for further studies.