Isle Royale Wolves Reach 50-Year High

Why this is here: Scientists observed no moose calves during this winter's survey, a first since the Isle Royale Wolf-Moose Project began in 1958.

Scientists estimate 37 gray wolves now inhabit Isle Royale National Park in Michigan, a remote archipelago near Canada. This number represents the highest wolf population on the island in almost 50 years. Researchers with the Isle Royale Wolf-Moose Project completed their annual survey in March, observing wolf packs and tracking moose.

The moose population has decreased to roughly 524 animals, contributing to a more balanced predator-prey dynamic. Ecologist Rolf Peterson notes the populations are approaching a historical low for moose and a high for wolves. The study of this relationship began in 1958 and is the longest continuous predator-prey research project in the world.

Wolves likely crossed to the island from Canada via an ice bridge in 1948. Recent wolf population boosts came from translocating 19 wolves to the island in 2018 and 2019, aiming to improve genetic diversity.

Though the ecosystem appears to be stabilizing, balsam fir trees—a key food source for moose—show record-low growth rates after years of heavy browsing. Researchers continue to monitor the populations, anticipating a future decline in the wolf numbers as food becomes less abundant.