Recent snowfall critical for local weasels
JACKSON, Wyo. — The recent snowfall is critical for local weasels, whose camouflage defense in the winter is dependent on a white, snowy landscape.
While many animals in the area, from grizzly bears to ground squirrels, hibernate throughout the winter, weasels remain active in the Greater Yellowstone Ecosystem (GYE). According to John Stephenson, wildlife biologist for Grand Teton National Park (GTNP), the weasel’s transition from brown to white fur during the changing of seasons allows them to camouflage against the snow.
Stephenson tells Buckrail that studies indicate it takes about three weeks, roughly 17 to 21 days, for weasels to change color completely. He notes that this transition occurs as a response to shortened daylight and not a change in temperature. Hormones trigger weasel bodies to shed brown summer fur and regrow white fur, a special genetic adaptation for northern species.
Long- and short-tailed weasels do retain a black tip on their tail despite their coat transformation, another advantage against predators. Stephenson says the black tip draws a predator’s attention to the weasel’s tail, so that coyotes, owls, hawks, eagles, wolves, bears or foxes will miss the weasel’s body in an attack and allow it to escape.
Least weasels, which are the smallest carnivore in North America and classified as “very rare” in the state by the Wyoming Game and Fish Department, don’t have this black-tipped trait in either summer or winter.