A new study from Michigan Technological University shows that the moose of Isle Royale are getting smaller. A comparison of moose skulls collected over the past 40 years revealed a 16% decline in overall size. That's in spite of a booming population.
Rolf Peterson, one of the authors of the study, says the change in size is due to poor nutrition early in life, and that can be attributed to a lack of predators and climate change.
Isle Royale's wolf population has been on the decline, and with a lack of predation, moose have overpopulated the island, resulting in a shortage of food. Warmer winters have also increased the prevalence of ticks and other parasites that affect the health of moose.
"We might expect it to resolve if and when wolves are returned to the island, and that's an announcement we expect pretty soon from the National Park Service," says Peterson.
However, repopulating the island with wolves would not be a quick fix. Peterson says malnutrition in a female moose affects offspring for three to four generations. That means the moose of Isle Royale will have a long way to go, even after the stress of overpopulation is relieved.