Only three wolves left on Michigan island

Inbreeding the likely cause of dwindling numbers

Only one pup (left) and two adult wolves remain on Isle Royale in northern Michigan, the site of a decades-long study of wolf-moose interactions. The pup appears hunched, with an extra skinny waist and deformed tail. Researchers think it won’t live more than a year.

ROLF PETERSON

By Teresa Shipley Feldhausen

April 22, 2015 at 11:02 am

The longest running study in history on predator-prey interactions may be at an end, say Michigan Technological University researchers. The reason: nearly all the predators have died.

Only three wolves remain on Isle Royale, a wilderness island in northern Michigan and the site of a 57-year-old study on wolf-moose interactions. Wolf populations on the island, once numbering about 50, are at their lowest level since the study began in 1958. Researchers think inbreeding is probably to blame for the most recent wolf die-off, which leaves just two adults and one sickly pup.

Researchers have little hope that a wintertime ice bridge will bring enough new wolves to Isle Royale for a “genetic rescue,” both because the remaining wolves may not mate with them and also because the frequency of ice bridge formations decline each year.