Lowly muskrat has big role in wetland ecosystems

What are muskrats, and why are they important to the St. Lawrence River?

Biologists for the U.S. Wildlife service and other agencies consider muskrats one of the most critical pieces of the wetland ecosystem, where they clear the water for fish and other animals.

Muskrats live in marshy areas, building lodges from mud and sticks. The rodents weigh from 2 to 4 pounds and are about 2 feet long.

Along the St. Lawrence, a relatively low muskrat population is to blame for thick stands of cattails, researchers say. Muskrats eat a wide variety of aquatic life, including cattails and other vegetation, frogs, insects and slow-moving fish. In turn, they are eaten by birds of prey.

Muskrats tunnel through stands of cattails, opening waterways and providing a habitat for other animals. Northern pike and other fish are more numerous in waters cleared by muskrats.

Their abandoned lodges sometimes are inhabited by turtles or other animals and also provide fertile ground for seeds to germinate.

They have webbed back feet for aid in swimming — their dens are sometimes accessible only from underwater — and they can swim backward.