I’ve heard them called muskrats on steroids. They’re the kudzu of the animal world, an uncontrollable pest introduced from South America. These semi-aquatic rodents can grow to 30 pounds. In the process they eat a lot of vegetation.
Many introduced species have changed the existing habitat for native plants and animals. Nutrias do more than that. They consume habitat.
Adult nutrias are about 14 inches long from the nose to the base of the tail. Their round hairless tails are slightly longer than the bodies themselves. Coloration is brownish, and both sexes are similar in appearance and weight. They have numerous long whiskers and orange teeth. Hind feet are webbed except for their baby toes.
Reproduction is prolific. Nutria may breed in any month of the year. One male usually has 2 or 3 mates which share the same burrow. Female nutria mature by six months of age and female nutria usually have two litters per year. Many females breed within two days after giving birth to a litter. Litter size varies but averages about five offspring.
Their appetite is insatiable and they yank out vegetation by the roots. They can eat up to 25 percent of their bodyweight each day. This, along with their constant digging causes soil to enter our waterways, setting in motion a destruction of living conditions for our native species of mammals, birds, reptiles, amphibians and fish.
Murky water and dead vegetation soon leads to lower oxygen levels and a change in the type and number of aquatic invertebrates. Sometimes what we don’t see can be even more damaging to a habitat that what we do see.
Nutrias are shy creatures and prefer to spend much of their time in their burrows when not eating. They seldom are seen sunning themselves out in the open, so we often don’t notice how many there are in an area.
When food supply in marshes and ditches is depleted these vegetarian eating machines move on to nearby cropland. In water they are graceful and elusive, but on land they are less formidable and easier prey for land predators including people.
Nutrias were introduced into this country back in the 1930’s. The goals were to clear out aquatic vegetation and provide a source of fur. There are two problems with this. First, nutria won’t graze underwater vegetation or algae. Second, the fur industry has taken a huge hit since the popularity of the animal rights movement.
We could cut down their population by including them in our diets. I’ve never eaten nutria, but I’ve been told their meat is similar to muskrat. I’m a big fan of that rodent, so I’ll have to try nutria sometime soon. They eat a healthy diet and meat is lean.
One obstacle encountered with nutria infested areas is something called ‘nutria itch.’ This is caused by a nematode. This parasite is not found in nutria meat, but it is present in waters where they live. I suggest washing thoroughly when encountering nutria infested waters, but don’t be paranoid of the outdoors.
Ted Manzer teaches agriculture at Northeastern High School.