Moose remain a fixture in Minnesota’s northern wilderness. As the largest member of the deer family, the moose is a symbol of the state’s deep boreal forests. The population is concentrated in a specific region, where these massive herbivores continue to browse on willow and birch despite environmental pressures.
Current Distribution in Minnesota
The vast majority of Minnesota’s moose population is confined to the northeastern corner of the state, an area often referred to as the Arrowhead region. This primary range is characterized by the boreal forest, acidic peatlands, and abundant wetlands that stretch across the Superior National Forest and the Boundary Waters Canoe Area Wilderness. The current distribution is sharply contrasted with the historical range, which once included a substantial population in northwestern Minnesota.
The northwestern population suffered a catastrophic decline and is now considered nearly extirpated, with fewer than 100 individuals remaining. Consequently, the focus of research and management is almost entirely on the northeastern herd, which represents the last viable population in the state.
The Steep Decline in Population
While moose are present, their current numbers reflect a dramatic reduction from historical highs, placing them on Minnesota’s list of species of special concern. Aerial surveys conducted by the Department of Natural Resources (DNR) documented a peak northeastern population of approximately 8,840 animals in 2006.
The state experienced a major population crash shortly after, with numbers plummeting by about 60% between 2009 and 2013, reducing the herd to a fraction of its previous size. In recent years, the population estimate has fluctuated around a semi-stable number, hovering near 3,700 animals, such as the 2024 estimate of 3,470 and the 2025 estimate of 4,040 animals.
Major Factors Driving Population Loss
The sharp decline is attributed to a complex and interconnected web of biological and environmental threats, which are exacerbated by a changing climate. One of the most significant biological threats is the brainworm, Parelaphostrongylus tenuis, a parasitic nematode that is transmitted from white-tailed deer. Deer are the natural host for this parasite and have co-evolved to carry it harmlessly, with the adult worms living safely in the tissues surrounding the brain and spinal cord.
Moose, however, are an abnormal host, meaning the parasite’s larvae do not follow the correct path to the meningeal tissues. Instead, the larvae migrate directly into the central nervous system, causing severe mechanical damage and inflammation in the brain and spinal cord. This neurological damage results in symptoms like stumbling, paralysis, and disorientation, ultimately leading to death. The brainworm is a major mortality factor where deer and moose ranges overlap.
Another significant parasite is the winter tick, Dermacentor albipictus, an ectoparasite that feeds on the moose’s blood. Moose have always coexisted with ticks, but warmer and shorter winters have created conditions that allow a much higher number of tick larvae to survive and thrive. This results in massive tick loads on individual animals, sometimes tens of thousands per moose, which leads to severe blood loss, hair loss, and winter-stress anemia.
The overarching factor linking these biological pressures is climate change, which causes direct physiological stress on the animals. Moose are highly adapted to cold climates and begin to suffer from heat stress at relatively low temperatures, often around 60 degrees Fahrenheit. When overheated, moose will reduce their foraging time and activity, leading to poor nutrition and compromised immune systems that make them more vulnerable to parasites and disease.
State Efforts for Conservation and Research
The Minnesota DNR and partners, including the Fond du Lac Band of Lake Superior Chippewa, have implemented extensive research and management initiatives in response to population challenges. Researchers conduct annual aerial surveys across 435 plots in the northeastern range to estimate population size and track long-term trends.
Researchers utilize advanced methods like fitting adult cows and calves with GPS collars to track movement, habitat use, and survival rates. When a collared animal dies, a full necropsy is performed to determine the exact cause of mortality, providing detailed scientific data on the role of parasites, disease, and predation. The state also engages in habitat improvement work, such as restoring thousands of acres of moose foraging areas by promoting the growth of preferred plants like willows and aspens.