The most widespread mustelid in the Western Hemisphere, long-tailed weasels inhabit open woodlands and forest clearings from southern Canada to northern South America. While fairly common throughout the U.S. (with the exception of open deserts in the Southwest), these aggressive hunters are primarily nocturnal and are not often encountered. On the other hand, they are active throughout the year and are best observed at dawn or dusk, especially during the colder months.
Molting in both the spring and the fall, those that live in northern latitudes turn white or creamy yellow during the colder months while more southern residents retain a cinnamon-brown dorsal coat throughout the year; in all areas, the tip of their tail remains black. Long-tailed weasels are solitary for most of the year, marking their territories with musk from anal glands. They mate in mid summer but implantation of the fertilized eggs is delayed; 4-8 kits are generally born in mid spring and remain with their mother until late summer. Female offspring are able to mate during that first summer while males are not sexually mature until the following year.
Using abandoned dens, long-tailed weasels live within rock piles, beneath stumps or under mounds of brush. They feed primarily on mice, voles, shrews and other small mammals but also attack larger prey such as chipmunks, squirrels, rabbits, reptiles and small birds; eggs are also consumed on occasion. Their natural predators include hawks, owls, coyotes and rattlesnakes; kits are vulnerable to a wider range of enemies, including fox, smaller snakes, ravens and magpies. Indeed, despite their aggressive nature, most long-tailed weasels die within their first year and few live more than 3-4 years in the wild.
