Thursday, November 5, 2009

Nature Guide: Muskrat and Opossum

It's not as easy to see most mammals as it is to see flowers or birds. Mammals keep out of sight and some of them are nocturnal. If you're patient and you know what to look for, two small mammals you may see in our area are the muskrat and the opossum. These two are active at night and you are most likely to encounter them at dawn or dusk. Our Nature Guide Jon Latimer gives us some information to help us recognize these small animals.

"The muskrat is found wherever there are lakes, streams, canals or wetlands. Smaller than a house cat, it has short, dense fur which is medium to dark brown on its back and lighter brown or silvery on its belly. A muskrat's long tail is scaly and flattened from side to side, which helps it swim.

"Muskrats spend much of their lives in water and can stay under for up to 15 minutes. They often follow trails that they make in swamps and ponds, feeding on aquatic vegetation, clams and frogs. They do not store food for the winter and when the water freezes, they follow their trails under the ice, searching for food. In spring they often fight other muskrats for territory and potential mates.

"Muskrat family groups consist of a male and female and often as many as 10 or 11 young. They build nests to protect themselves from cold and predators. Where the water is deep enough, they dig a burrow into the bank with an underwater entrance. In marshes, they construct a conical lodge out of vegetation and mud.

"The Virginia Opossum (also known as a possum) is the only marsupial native to North America. This means that females carry their young through early infancy in a pouch, like a kangaroo. Also about the size of a house cat, an opossum has a pointed nose and a scaly prehensile tail that looks similar to a rat's tail. An opossum's face is white with black ears and its body is whitish gray. At night, its eyes shine dull orange when struck by light.

"An opossum is usually solitary. During the day it sleeps in the hollow of a tree, often with its head tucked under its body. At night it forages for fruits, worms, frogs, insects and garbage. It may wander widely, especially in fall. When it feels threatened, it will show its teeth and hiss and give off a disagreeable smell. If cornered, an opossum may "play possum" and appear to be dead. It really isn't playing, though. Research has shown that this reaction is an involuntary response to extreme fear.

"Females produce two litters each year, sometimes containing as many as 15 young. Babies, which weigh around 1/15 of an ounce at birth, stay in their mother's pouch for the first two months. Later they may ride on their mother's back, holding on to her tail with theirs."

Photo by Cody Pope