Let’s talk about Michigan’s 2 invasive mammals: A large, destructive rodent and aggressive wild boars

Nutria (L - USDA), wild boar (R- Florida Fish and Wildlife Conservation Commission) (USDA, Bugwood.org)

There are two mammals on Michigan’s list of invasive species to watch out for.

The first one is a large, destructive rodent that has not yet been found in Michigan -- Nutria.

The second is the aggressive wild boar, which has been prohibited in Michigan since 2012.

Wild boar / Russian Boar

Wild boar are known to be established in Michigan and were banned in 2012.

Before they were banned, wild boar were found in 65 of Michigan’s 83 counties including Macomb, Oakland, Livingston, and Washtenaw counties. Now, they’re only found in three counties.

According to the Michigan Department of Natural Resources, many of the wild boars found in Michigan escaped from game ranches. They carry disease, destroy crops, threaten animals and people and provide no benefit other than sport hunting.

Before they were banned in 2012, hunting was big business for the owners of approximately 65 game ranches across the state.

Map: Feral Swine Populations by County in 2021. (USDA)

Wild boar were first brought to the United States in the 1500s. Free-range livestock and escapes caused the first establishment of feral swine populations in the country.

In the 1900s, the Eurasian or Russian wild boar were introduced into parts of the United States for the purpose of sport hunting, according to the USDA. Currently, wild boar populations are made up of escaped domestic pigs, Eurasian wild boars and hybrids of both.

They have been reported in at least 35 states and their population is estimated to be more than 6 million and rapidly expanding.

They can be identified through their long, straight, narrow snout, dark-colored or camouflage coat and light-tipped bristles.

They are typically found in mixed forest and agricultural areas. They feed on hard mast and agricultural crops. They also use wetland habitats throughout the year.

They are known to eat what they can and when they can -- that includes crops, bird and reptile eggs, insects and insect larvae, fawns and young of domestic livestock, grasses and forbs, tree seeds and seedlings, nuts, roots, and tubers.

The wild boar are aggressive toward humans and can transmit several diseases.

Other names: Wild boar, wild hog, feral pig, wild boar, Old World swine, razorback, Eurasian wild boar, Russian wild boar


Nutria has not yet been detected in Michigan, but officials want residents to be aware of them.

These large, destructive, semi-aquatic rodents make their homes in farm ponds, drainage canals, bayous, freshwater and brackish marshes, swamps and rivers. They eat bulrush, cordgrass, roots and rhizomes of tubers and cattails.

They carry several diseases and parasites that can infect people, pets and livestock. Their feeding, digging and rooting habits cause erosion and convert healthy marsh into an open water habitat.

They’re found in the Gulf of Mexico coast, Atlantic coast and Pacific Northwest. They were introduced for fur production. Michigan officials believe they could become established in Michigan if they’re released intentionally or accidentally.

They can be confused with the American Beaver and Muskrat. Nutria are around 2 feet long and have dark brown fur, large yellow or orange-colored front teeth, a thick rat-like tail covered with bristly hairs, and long, white whiskers on either side of their nose.

Other names: Coypu, coypu rat, nutria rat, swamp beaver

About the Author:

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.