Each January, before they fly to snowbound Isle Royale in Lake Superior, ecologists Rolf Peterson and John Vucetich guess how many wolves they’ll spot. This pocket of wilderness in Michigan is home to the world’s longest running predator-prey study, of wolves and moose. This year, Peterson figured that they’d likely find a mere seven wolves, given complications of inbreeding in the dwindling population. But the island held only three wolves, as the researchers from Michigan Technological University (MTU) in Houghton announced today. “The collapse of the wolves was beyond our expectation,” Peterson says.
The three wolves included a pair, probably the last known to have reproduced, plus a notably smaller wolf that might be their pup. The other wolves are presumed to have either died or left the island last year, in a reverse of how carnivores originally came to Isle Royale, when a bitter winter completely froze the channel to the mainland.
But even as the famed predator-prey study on Isle Royale appears to be on its last legs, other researchers may have caught the birth of a similar natural experiment: Across the lake in Canada, three mainland wolves crossed the ice to a smaller island with different prey and seem to have settled in, as population ecologist Brent Patterson of Trent University in Peterborough, Canada, will report at a wildlife meeting next week. “It’ll be very fascinating to watch,” Patterson says.