Badgers Weasels Skunks and Otters: Mustelidae

Physical characteristics: Ermines have slender bodies, useful for pursuing prey through narrow passages. They have a triangular head, rounded ears, and a long neck. Long, sensitive whiskers help track prey. The fur changes with the season and acts as a camouflage (KAM-uh-flaj), white in winter to blend in with the snow and brown with yellowish undersides and feet in summer. Their tails measure 2 to 4 inches (3 to 10 centimeters) and have black tips all year-round, which helps distract attention from the predator's body. The body is 6 to 10 inches (15 to 25 centimeters) long. Ermines weigh just 4.4 to 12.3 ounces (125 to 350 grams).

Geographic range: Ermines live in the United States and Canada, Asia (including Japan, India, Mongolia, and Siberia), Europe (including Scandinavia and Ireland), Algeria, and Greenland.

Habitat: Ermines prefer forests, grasslands, and marshy plains that provide cover and prey. They live in tree roots, hollow logs, and

An ermine turns from its brown fur color for summer to its white color for winter. The fur changes with the season and acts as a camouflage, helping the animal blend in with its surroundings. (Erwin and Peggy Bauer/Bruce Coleman Inc. Reproduced by permission.)

burrows, holes or tunnels, inherited from their prey, usually lining their nest with fur from their prey.

Diet: Ermines are carnivorous, eating rodents, rabbits, ground squirrels, birds, and insects. They eat as much as half their body weight in food and store extra food for later use.

Behavior and reproduction: Ermines are loners, except for breeding pairs and mother-offspring groups. They use musk, an anal secretion, to mark territory and as a signal for mating. Ermines also communicate through squeaks, trills, and screeches. They are active throughout the day and night. Expert hunters, they prey on animals several times their size, killing them with a bite at the back of the neck.

Ermines mate in late spring to early summer, but the fertilized egg undergoes delayed implantation, waiting nine to ten months before attaching to the uterus to resume development. Females give birth to one or two litters of four to eight offspring the following spring and raise the young alone. Females become sexually mature, capable of reproducing, at two months of age, while males attain sexual maturity at one year. It is not unusual for adult males to mate with very young females, sometimes before they are weaned from their mother's milk. This ensures new generations even if males might not be around for mating.

Ermines and people: Some people value ermines for killing rats and mice. Americans used the black-tipped tails as ornaments, while European royalties made ceremonial robes out of the whole fur.

Conservation status: Ermines are not a threatened species. ∎