A new study focuses on Minnesota moose to understand why their numbers are declining. Between 2006 and 2017, the state saw a 58% decrease in moose population in the northeast. The culprit? Brainworm, according to a news release.

Brainworm is a parasite that infiltrates the nervous system, resulting in paralysis and death. A new study published in the Journal of Wildlife Diseases found that Minnesota moose eat a lot of gastropods – aka slugs and snails – which are hosts for the brainworm parasite.

The study was a collaboration between the University of Minnesota (UM) and the Grand Portage Band of Lake Superior Chippewa (GPBLSC). To conduct the research, Tiffany Wolf, a professor in MN’s College of Veterinary Medicine, and Self Moore, director of biology and environment for GPBLSC, analyzed 258 fecal samples that were collected on Grand Portage tribal lands from both moose and deer to determine the “consumption of gastropods.” Moose ate three species of gastropods with one being specifically “well-documented” as a host for brainworm.

“Because this work is done in partnership with the Grand Portage Band, for whom moose are an important subsistence species and source of cultural preservation, a primary motivation of our research is maintaining healthy moose populations on and near the Grand Portage Indian Reservation,” said Tyler Garwood, a researcher in the College of Veterinary Medicine who was part of the study. “More broadly, moose are an iconic species for our state and fill an important ecological niche as the largest herbivore in the northwoods ecosystem.”

Researchers can use this information to modify habitat to limit or decrease the density of that type of gastropods in areas where moose are commonly found.

“The Grand Portage Band of Chippewa has been leading extensive efforts to restore moose in Minnesota for nearly 18 years to support the vital lifeways of the Anishinaabe,” said Moore. “The overall goal is to conduct population-level applied research and restoration so that the great-grandchildren of our children, seven generations from now, will continue to be able to use our natural resources as our great-grandparents were able to do. We incorporate Traditional Ecological Knowledge and modern science in our practices to best steward our natural resources.”