Mammals of Wisconsin

Lost and found

In the early 1800s Wisconsin still had elk, wolves, cougars, and even a few bison. Unregulated hunting, logging, and the plow took them within decades. The last 150 years of the state’s mammal story is about what came back, what was brought back, and what grew beyond its old numbers.

Elk

Elk were eliminated in the 1880s by unregulated hunting and habitat loss ¹. In 1995, 25 elk were reintroduced near Clam Lake in the north, and a second reintroduction beginning in 2015 started a herd in the central forest near Black River Falls. Together they’ve grown to more than 400 ¹. The native Eastern subspecies went extinct in the late 1800s, so the reintroduced animals are Rocky Mountain elk ¹.

Elk are about three times the size of a deer; a mature bull stands 5 feet at the shoulder and weighs 600 to 900 pounds ¹. In September, bulls bugle during the rut ¹, and the Clam Lake area’s forest openings are the place to hear them. Elk are one of three deer-family members in Wisconsin, with white-tailed deer and the occasional moose that wanders in from the north ¹.

Gray wolves

Wolves were wiped out of Wisconsin by the 1950s and recolonized on their own from Minnesota starting in the 1970s. The DNR estimated about 1,162 wolves in 321 packs in late winter 2026, mostly in the far north and northwest and in the central forest ². That was a 5 percent dip from the year before and close to the five-year average, which the DNR reads as a population that has reached carrying capacity, the number the habitat can support ².

Legally, wolves are federally listed as endangered in Wisconsin. Hunting and lethal control of problem wolves are prohibited, and it’s unlawful to shoot a wolf except when there’s an immediate threat to human safety; suspected attacks on livestock or dogs go to USDA Wildlife Services ³. Federal status has changed several times, so check the DNR’s current rules.

Black bears

Wisconsin’s black bears number more than 24,000 ⁴. Their main range is the northern third of the state, but there are healthy populations in central and western Wisconsin, and the range keeps spreading south ⁴. They’re the only bear here; adult males usually weigh 125 to 550 pounds and females 90 to 375 ⁴. For a homestead in bear country, that means bird feeders taken down in spring, garbage and livestock feed locked up, electric fence around beehives and chicken runs.

White-tailed deer

Deer are the one big mammal that’s more common now than when settlers arrived: logging opened the forest, farms fed them, and wolves and cougars were gone. Their numbers reshape the woods. In UW–Madison research on northern forest sites, plants like trillium, orchids, and lobelias declined outside deer fences while grasses, sedges, and ferns increased, with at least 40 percent of 60 years of understory change traced to deer ⁵. (The Spring Wildflowers lesson has the details.) Deer hunting is, among other things, forest management.

The smaller cast

Most of Wisconsin’s mammals are small and easy to miss: beavers rebuilding wetlands one dam at a time, river otters, fishers and martens in the north woods, bobcats, coyotes and red and gray foxes, porcupines, flying squirrels that most people never see, and bats, several of which have been hit hard by the fungal disease white-nose syndrome. The Tracks and Sign lessons later in this course are how you find them.

What to take from this

Elk were gone by the 1880s and came back from 25 animals in 1995 to more than 400. Wolves recolonized on their own and number about 1,162 in 321 packs (2026), at carrying capacity, and are federally endangered: no shooting except for human safety. Black bears are over 24,000 and spreading south. Deer are more abundant than ever and reshape the forest understory.