Isle Royale Wolf Population Nears Historic High as Moose Numbers Plummet
A near-record high wolf population and near-record low number of moose characterized the 2026 Isle Royale Winter Study, a long-running population survey of wolves and moose led by Michigan Tech researchers on Isle Royale National Park.
Co-led this year by Sarah Hoy and Rolf Peterson (both CFRES), the winter study was conducted Jan. 22 through March 3 in bitterly cold conditions that, for a time, caused an ice bridge to form from the remote island archipelago to the mainland.
In their 2025-2026 annual report, co-authors Hoy, Peterson and John Vucetich (also CFRES) estimate that 37 wolves inhabited the island during the winter study. The wolf population hasn’t reached this level since the late 1970s.
Their survey findings for moose were equally dramatic, though on the other end of the spectrum, with the moose population estimated at 524. That’s a 75% drop since 2019, when the number of moose on Isle Royale topped 2,000. The lowest number of moose ever recorded was 385 in 2007.
“The wolf and moose populations are now approaching the edge of where they have been in the past, with moose low and wolves high,” said Peterson.
Find more observations from this year’s winter study and access the newly released annual report at Michigan Tech News.