The weasel, a stealthy hunter that changes its fur coat
By Robert A. Hedeen, Naturalist
The long-tailed weasel is a beautifully adapted animal that ranges across a good portion of the United States. The weasel is a member of the family Mustelidae that includes minks, ferrets, skunks and a few others. Members of this family possess potent anal glands, but, in the case of the weasel, they are not as highly developed as the defensive weapons of the skunk.
A course in the life and lore of the weasel should be on every rats educational curriculum of study for survival. This relentless, elongated hunter is tailor-made for rat holes, popping in and out with such terrifying preoccupation that it soon puts itself out of business in one rat burrow system and must move on to another. It can and will take to the high rafters, if occasion demands, to pull down a rat that has tried to escape. It is also an adept swimmer.
Weasels kill with silent efficiency, pouncing on a prey animal with snake-like speed. They strike near the base of the hapless victims skull and hang on tightly until the sharp fangs have inflicted a mortal wound. After the kill has been made, the weasel may lap a little blood and eat a little brain tissue, then take a time out for a snooze before finishing its meal. The prey may be consumed on the spot, or dragged home to its den to feed the young. Weasels hunt their prey by detecting a scent or sound and then follow the prey and strike like a bolt of lightning.
Weasels are small animals with a diminished head and ears, a pointed nose, and a long bushy tail. Sensitive whiskers help guide it through tight spots where their hunting forays may require them to go. It has been said if you took a weasel and stretched it out like a piece of taffy, and shortened the legs, you might be able to call it rat-sized. Males are larger than females and may weigh up to a half-pound. The much smaller females are about the size of our familiar chipmunk.
The fur is composed of short, soft under fur covered by shiny guard hair. They are normally cinnamon brown in color with a whitish underside. However, twice a year, in the spring and fall, weasels shed their coats. Those living in the South retain their brown color throughout the year, but those inhabiting northern climes grow a white coat in the fall and become brown again in the spring. The tip of the tail remains dark when the white coat is assumed.
Southern weasels taken to the North and reared there will not turn white, but northern animals taken to the South and reared in the wild will turn white no matter how mild the winter may be. Wildlife biologists attribute this in part to genetics and photoperiodicity (the amount of light in the atmosphere during the winter).
This change of coat during the winter months is an obvious survival adaptation that is characteristic of some other northern mammals. The dark tip of the tail is said to fool potential enemies such as foxes, hawks, owls, and bobcats in winter. The predator is more apt to pick up on the black tip of the tail against a white background than the rest of the body, thus giving the weasel a chance to escape.
Weasels prefer other small mammals for their daily ration, but will consume fruits and berries during the warm months. Snakes, lizards, amphibians, and birds, including chickens, will also be eaten if they can be caught. They have a high rate of metabolism, as when fed colored mice in captivity, the remains of the rodents pass through the weasels digestive system in about three hours.
For most of the year, the weasel is a loner that avoids the company of his kin. In the summer, however, the sexes get together to comply with the basic law of nature that requires the species to be preserved. After mating, the fertilized eggs undergo only limited embryological development. The early blastula stage (a hollow sphere of cells similar in structure to a ping pong ball) is reached but is not implanted. Rather, development of the embryo is arrested until the following March when development starts anew and implantation occurs. The annual litter of five or six arrives in May when conditions for survival are optimal.
I recall an incident when weasels helped the U.S. Army during the Cold War. A large quartermaster depot at Perigueux, France, faced a severe rat problem. The rodents were destroying large amounts of foodstuffs meant for American troops and had defied all attempts to trap or poison them. A Frenchman, who worked for our Army, suggested to the commanding officer that he could solve the problem and was given the go ahead. He raised weasels as a hobby and released five or six of his pets into the warehouse. In a matter of two weeks, no evidence of active rodent infestation could be found. The commanding officer is reported to have exclaimed with joy, Vive la belette (weasel)!
Dr. Robert Hedeen is a former resident of Marylands eastern shore and resided in the Chicago area from 1960-1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.