long-tailed weasel (Mustela frenata) is the most common
carnivore in North America. Though these weasels inhabit a variety
of habitats, from upland brush and woods to semi-open forest areas,
in Idaho they are most often found in rocky, mountainous regions.
The are frequently seen on in the INL.
The long-tailed weasel has a long and slender body, brown fur, short
legs, and a tail measuring up to seven inches in length. The tail,
the longest of any North American weasel, has a black tip. This
black tip confuses predators into mistaking the tail for the head,
thereby drawing the focus of an attack away from the vulnerable
portion of the body. During the winter, the weasel changes from the
brown summer color to entirely white, except for the black of its
eyes, nose and tip of the tail.
Long-tailed weasels also have between 28 and 38 long, sharp teeth
that they use to deliver a sharp, killing bite to back of their
prey’s neck. They find prey mainly by scent, darting in and out of
rodent burrows, checking brush, and rock crevices. Their long, thin
body makes it easy for them to follow its prey into burrows.
Because of the weasels’ slender body shape, they don’t store heat
well and have a very high rate of metabolism. They may eat about 40
percent of their body weight every day! Most of their diet is made
up of small mammals like mice, voles, rabbits, gophers and
chipmunks. They will occasionally eat birds and insects.
Long-tail was once thought to be primarily nocturnal, but evidence
has shown that they may hunt during daylight hours, as well,
especially during the summer. Long-tail weasels do not hibernate,
and often will kill more animals than they can eat at one time and
cache the carcasses for later. Weasels occasionally go on killing
sprees, as instinct dictates that they procure food when available
and then store it. For this reason, a weasel in a chicken yard is
disastrous. Although they are notorious for destruction of poultry,
the damage they do is far outweighed by their value as destroyers of
Weasels are curious
and bold and will often stand up on their hind legs for a better
look at you if you avoid any quick movements. They make a
rapid "took-took-took" sound, hiss, purr, chatter, grunt and
screech. When annoyed, they stamp their feet or emit musk from their
anal scent glands.