Recent controversy has arisen as to whether muskrat or nutria were sighted in the Arboretum’s wetland. Though not present at the time, I decided to research differences between the two rodents so as to be prepared for future sightings.
Muskrats are much smaller than nutria, weighing only four pounds and reaching an average length of 16 inches. Their tails, which grow nearly as long as their bodies and are flattened on the sides, whip like snakes in the water. Muskrats have yellow- or orange-colored front teeth and black whiskers.
Nutria, native to southern South America, have conspicuous white whiskers and large orange teeth. Nutria can grow up to two feet in length and weigh up to 12 pounds. Their 13- to 16-inch round tails trail smoothly behind them in the water, while their highly arched backs lend a humpbacked appearance on land.
The feeding and burrowing habits of nutria destroy root mats that secure wetlands, ponds, and rivers. Nutria were introduced in Maryland in 1943; as their numbers have dramatically increased over the years, so has related loss and degradation of coastal wetlands from erosion.
In 2012, the presence of nutria was confirmed at Mud Mill Pond in northern Caroline County. The Arboretum, dedicated to the preservation and conservation of the Chesapeake Bay region’s native landscapes, is hopeful that its wetlands remain free of this non-native pest.
by Jenny Houghton
Youth Program Coordinator