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Short-tailed Weasel Fact Sheet 1

Short-Tailed Weasel (Ermine)Mustela erminea

The short-tailed weasel (Mustela erminea)is the second smallest member of the weasel family. Like the long-

tailed weasel and its other relatives, the short-tailed weasel, also

known as the ermine, is a predator. The short-tailed weasel

occupies a wider variety of habitats than the long-tailed weasel,

which include wetlands, forests, and fields. It is trapped for its fur,

but not avidly.

Vermont Wildlife Fact Sheet

Physical Description

Like all members of the

weasel family, the short-tailed

weasel has a long, slender body,short legs, and a long neck. It can

grow to a length of seven to 13

inches and a weight of one toseven ounces. The male is

noticeably larger than the female.The short-tailed weasel is

capable of quick, agile

movements. The coat is reddishbrown on its back, head, sides

and tail. However, it is white in

color under the chin and on its

belly. The tip of its tail is black,similar to that of a long-tailed

weasel. In the summer an

excellent field marking, besidesthe obvious tail length, is that the

short-tailed weasel has a white

line down its hind legs and thelong tailed does not. In winter,

the short-tailed weasel will molt

to an all white coat, except for

the tip of its tail, which remainsblack. It is referred to as an

ermine in this color phase.

Life Cycle

Short-tailed weaselsbreed form late spring to early

summer, but development of theembryos does not begin until the

following spring. After mating,

the fertilized egg remains inlimbo through a process known

as delayed implantation. During

this process, all development of

the embryo ceases forapproximately eight to nine

months. After this time, the

fertilized egg is implanted intothe uterus wall and development

of the embryo begins. In March,

as the days begin to lengthen,

the development of the fetus willresume. This unique process is

thought to benefit the weasel byallowing the female to give birth

when environmental conditions

are at their most favorable.

After a total gestationperiod of 280 days, the young

are born in April and May.

A litter can range in size fromfour to 15 but averages six to

seven young, or kits. When thetiny weasels are born, they havefine white fur, and their eyes and

ears are sealed.

The kits grow rapidly. At

three weeks, they have a welldeveloped mane and their eyes

are open by five weeks. The

youngsters are soon travellingshort distances with their mother,

who has the responsibility ofraising the kits. Young males at

seven weeks are as big as their

mother and, by the eighth week,the male and female kits are able

to hunt on their own. The female

kits reach sexual maturity when

they are two months old, and it isnot uncommomn for them to

breed the first summer of their

lives. The male kits, however,do not mature until one year old.

Food Items

Like the rest of theweasel family, the short-

tailed weasel is a carnivore,

preying on a variety ofanimals. The short-tailed

weasel takes voles, shrews,

cottontail rabbits, rats,chipmunks and nesting

birds. Male short-tailed

weasels normally take larger

prey items than the females.Short-tailed weasels

will also store, or cache,

extra food for later use.When their preferred food

supply is low, they will eat

prey that is easier to catch,like fish, birds or insects. In

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Short-tailed Weasel Fact Sheet 2

summer, they also eat fruit

and berries.

Habits & Habitat

Short-tailed weasels can be

found in a variety of habitats

ranging from wooded areas tograsslands. Short-tailed weasels

require areas of heavy cover but

tend to avoid dense forests.Weasels will burrow, or build, a

nest in rock or wood piles, in a

hollow tree, or under a building.Often, rather than building their

own nest site, they will simply

take over one of their prey's.Weasels are not social animals.

With the exception of thebreeding season, it is rare to find

a male and female together.Although these fierce predators

are active during the day, they are

considered to be nocturnal. Theyare quite aggressive and will

defend their territories from any

intruder. They are skilled huntershaving great speed and agility.

They can also swim and climb.

Abundance

Short-tailed weasels arecommon throughout their range.

They prefer open woodlands and

transitional areas between forestsand fields located near a water

source.

History

The short-tailed weaselhas proven itself as an adaptable

species. As the landscape

changed over the last 150 years,

from intensive farming toabandonment, the short-tailed

population fluctuated, but has

remained an important species inVermonts ecological community.

Resource Utilization

Short-tailed weasels are

an important predator. They playa vital role in controlling

populations of rodents that might

otherwise damage agricultural

crops or transmit disease. Humansalso hunt them for their pelts. The

ermine's pelt (i.e. winter coat) is

considered to be of greater valuein the fur industry than its brown

summer pelage.

Management Efforts

Continuedmonitoring is conducted to ensure

that the short-tailed weaselremains healthy and abundant inVermont.

Illustration: W. Ferguson