After spending millions of dollars and tracking hundreds of moose with GPS collars, scientists have pinpointed the primary culprit behind the animal's ever-shrinking numbers in Minnesota.
It's the deer. Parasites they carry into Minnesota's North Woods have emerged as the leading cause of death for moose, state and tribal biologists have concluded.
But solving that mystery creates a thornier one: How can state wildlife managers balance efforts to save the iconic moose with the demands of hunters who want more deer in Minnesota's far North Woods?
Minnesota has an estimated 500,000 deer hunters, and they provide about $20 million a year to the state Department of Natural Resources while supporting powerful and well-organized hunting organizations.
"We don't have a Minnesota Moose Hunters Association," said Carrol Henderson, nongame wildlife manager for the DNR.
The strong pull of Minnesota's whitetail culture and its economic impact show up loud and clear in DNR surveys of landowners and hunters in that part of the state, as well as in the sometimes-contentious debate among citizen committees that advise the DNR on deer management.
"Deer hunting brings in more money to the state than moose," said Randy Bowe, a longtime hunter on the North Shore of Lake Superior and owner of a taxidermy business in Duluth. "I don't know of anyone who purchased land to moose hunt."
Minnesota's pine forest has always been the most southern edge of the moose country that stretches across the northern part of the continent. The huge animals used to roam across the top of the state, numbering more than 8,000 as recently as 2005. But in the past 12 years their numbers plummeted, and the 4,000 or so that are left congregate in the Arrowhead region between the Boundary Waters Canoe Area and the North Shore.
The speed of their demise flummoxed biologists and launched some of the most ambitious moose research projects ever conducted -- one by the DNR and another by the Grand Portage Band of Chippewa. Both relied on sophisticated satellite-connected GPS collars that tracked moose through their daily lives, and many to their deaths. Between the two studies, about 83 carcasses, or parts of them, were extracted from the woods and trucked to the University of Minnesota for moose autopsies.
They found that moose die for a lot of reasons. Wolves and bears eat their young and injure the adults. Bloodsucking ticks, which survive shorter winters in ever-greater numbers, weaken them. And the impact of climate change is still an open question.