Isle Royale wolf researchers were concerned this winter when they discovered the population had dropped from 16 to 9 in one year, but they couldn’t explain the decrease. A discovery this week finally helped explain part of the problem — the bodies of three adult wolves were found in an abandoned mine shaft.
“We found there had been a real catastrophe in early winter, before we arrived on the island in January,” Michigan Technological University population biologist John Vucetich said in a Michigan Tech news release. “There were three dead wolves from the Chippewa Harbor Pack in the shaft: a collared male that we had been unable to locate this winter, an older male — maybe the alpha male — and a female born in 2011.
“We believe the incident occurred between mid-October and mid-January. There is no way to know how the three wolves ended up falling into the pit, but very likely, accumulating snow and ice played a role in the accident.”
The discovery was especially concerning since only of the remaining nine wolves is believed to be a female. The young female that died could have been key for the population’s recovery. The risk of extinction for the wolf population is very high now, according to researchers.
Isle Royale is located in the northwest corner of Lake Superior. The island, which is a part of the state of Michigan, is isolated and small — just 207 square miles. Researchers have been studying the relationship between wolves and moose on the island since 1958 — the longest study of either wolves or moose in history. Researchers have been able to study the varying populations and cyclical relationship between the two species with almost no human interaction.
For more on the discovery, the full news release on the Isle Royale wolf population study is available on Michigan Tech’s website.