Total length: 11 to 16.5 inches.
Weights: 3 to 12 ounces.
Found in almost all land habitats near water.
Has the broadest ecological and geographical range
of the North American weasels. Prefers areas
with abundant prey. Avoids dense forest, most
abundant in late seral ecotones.
More of a generalist than the short-tailed and least
weasels. Feeds mostly on small mammals up to
rabbit-sized, but eats birds and other animals as
Primarily nocturnal, but sometimes active during the
day. Quite fearless and curious. Mainly
terrestrial but can climb and swim well. Nests
in old burrows of other animals. Mates during
summer; 205 to 337 day gestation; delayed
implantation; young born during April; litter size 4
Short-tail weasel - white line down inside of leg,
smaller. Least weasel - no black tip on tail,
smaller. Mink - nearly uniform dark brown.
Marten - heavier, much larger.
The long-tailed weasel, which is the largest of the
three weasels found in Montana and varies from 13 to 18
inches in length, including a 6 1/2 inch tail. It
is the long tail which gives it its name. They are about
2 to 3 1/2 inches high and weigh up to 12 ounces.
It has a long, slender, muscular
body with short legs. The head is small, with beady
eyes, small ears and a pointed nose. They move with
quick movements and a graceful, bounding gait. All three
weasels change color with the seasons, and there is no
color difference between the sexes. All the senses are
well developed in the weasel.
The long tailed weasel is much
the same in color as the short tailed weasel except
that, in some areas, it does not become white in winter.
The feet are dark brown in summer whereas the short
tailed weasel has pale yellowish feet in summer. The
tail has a black tip throughout the year. The molting
pattern is different than in short tailed weasels,
starting on the back in spring and causing a brindled
appearance to the facial markings.
The long-tailed weasel females mature at 3 to 4 months
and males mature at about one year. The breeding season
is in July. There is a period of delayed implantation
with a gestation period of 9 to 10 months. The period of
active pregnancy is 23 to 17 days.
Litter sizes varies from four to
thirteen, with an average of six to eight. The young are
born in April or May in nests constructed in underground
dens or hay piles. Mouse nests and burrows are often
used and heavily lined with fine grass and mouse fur.
The male begins to bring food to the den about 1 month
after the young are born. The young are weaned at the
end of 5 weeks and are able to hunt for themselves by 7
or 8 weeks of age. The family stays together until late
summer and then disperses. The life expectancy of
weasels is short, probably less than a year, although
they are capable of living as long as 6 years.
prey on small rodents such as mice, rats, voles, hares,
rabbits, and chipmunks. They also take shrews, birds,
birds eggs, frogs, bats, insects, earthworms and may
occasionally kill domestic chickens.
The weasel hunts by tirelessly
and persistently investigating every small hole,
crevice, bush or rock pile it encounters. They will
track prey by following their scent trails and generally
attack prey by ambushing and pouncing on it. They are
very quick and kill by piercing the base of the skull
with their teeth. The weasel frequently kills more than
it can eat and often caches leftover food. The weasel
can consume up to one third of its own weight in a 24
Weasels are curious, alert and bold. They are persistent
hunters who seldom remain long in their dens and may be
abroad hunting at any hour, although they are usually
most active at night. Weasels are active year round.
Weasels occasionally hunt in pairs but, for the most
part, are solitary except during breeding and rearing
season. They are good swimmers and can also climb trees.
All species emit a strong musk odor when alarmed, and
the weasel may stamp its feet when annoyed. Weasels may
mark their trails with droppings. Home ranges very from
30 to 400 acres.
Weasel populations often cycle with mouse populations.
Several parasites can infect weasels, such as guinea
worm and kidney worms. These probably have little impact
on the population.
Weasels are subject to predation
from hawks, owls, foxes, coyotes, dogs, cats and man.
In agricultural areas, weasels
are more common due to the practice of storing grain
which provides ideal conditions for mice.
Weasels prefer woodlands or open country with hedgerows,
thickets or fence rows. They are usually found near
water but are not semi-aquatic as is the mink. They
frequent stone piles, brush heaps, wood piles, hay
stacks, log piles and old abandoned buildings.
The long-tailed weasel is found
in almost all land habitats near water. It has the
broadest ecological and geographical range of the North
American weasel. It avoids dense forests.
The dens of weasels are shallow
chambers about 6 inches underground with two to three
entrances and are lined with mouse fur and grass.
The fur of the long-tailed weasel commands a higher
price because it is so much larger.
Weasels play an important role in
helping to control rodent populations.
Best Management Practices