Isle Royale Ice Bridge: Did Wolves or Moose Leave?

Isle Royale is surrounded by Lake Superior, and many believe that moose and wolves reached the island by swimming or crossing an ice bridge. Did any of them leave the island this winter using the ice bridge?

Moose and Wolves on Isle Royale

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Moose first appeared on Isle Royale in the early 1900s, probably swimming from Minnesota or Canada. Wolves followed in the late 1940s, crossing a 15-mile ice bridge from Ontario. This ice bridge provides animals the ability to travel to or from the island.

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Since 1948, wolves have been able to cross the ice bridge from Canada during winters cold enough to connect Isle Royale to the mainland. Over time, the island’s wolf population has declined due to inbreeding and possibly by wolves leaving via the ice bridges in winter.

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Wolves were reintroduced in 2018 by releasing 19 new wolves from Minnesota, Ontario, and Michigan to restore the predator-prey balance. Did an ice bridge that formed this winter allow for some wolves or moose leave Isle Royale?

Did Moose and Wolves Cross Ice to Leave Isle Royale?

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Ice bridges linking Isle Royale to the mainland usually form during the coldest months, from January to March, though they are becoming increasingly rare due to climate change. These temporary, weather-dependent crossings have historically allowed wolves to migrate between Minnesota or Canada and the island. Moose generally remain on the island but have occasionally used the ice bridges to move between the mainland and Isle Royale.

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According to MLive, a solid ice bridge connected Isle Royale to the Canadian mainland by January 29, 2026, remaining intact until February 14. By February 17 however, most of the ice had melted.

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Although researchers closely monitor wolves and moose on Isle Royale, they cannot track their movements on and off the island during winter unless the animal is wearing a GPS collar. Seven years ago, a GPS-collared wolf left the island via an ice bridge and never returned, though researchers continued to receive its signals for two years afterward.