Nature Bulletin No. 427-A October 2, 1971
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
The otter is the fastest, most agile swimmer of all our "land" animals
and has more fun than any of them. Long and lithe-bodied like his
smaller relatives, the weasel and mink, he is completely at home in
water and never found very far from it. His short legs with large 5-toed
webbed feet, and the long tapering powerful tail, are built for
An otter may be idling on the surface with slow porpoise-like rolls, or
cruising along underwater at about six miles per hour, but when he is
hungry and spies a fish -- goodbye fish ! He can dive, twist, turn and
swim faster than any trout or salmon. In winter he can swim a quarter of
a mile under the ice from one breathing hole to the next .
Adult otters are from 3 to 4 feet long, including the tail, and weight up
to 25 pounds. Their dense fur -- a dark rich brown with long glistening
guard hairs -- is somewhat lighter on the belly and grayish about the
face. It is one of the most durable of all furs and formerly one of the
most valuable. The ears are small and the head is rather broad and flat.
Their sight and hearing are not particularly keen but they have an
exceptional sense of smell and long sensitive whiskers which help them
catch their prey. In addition to fish, they eat lots of crayfish, frogs,
mollusks, aquatic insects, and occasionally a young muskrat or a
Otters den in burrows along the banks of streams and lakes, sometimes
in a hollow tree or fallen log, but the entrance is usually concealed
underwater. They are very shy and wary. The kits or cubs are born in
early spring -- commonly 2 or 3 in the litter. Blind and helpless for 5
weeks, they do not venture out until about 3 months old. Then the
mother teaches them to swim, sometimes forcibly, and catch food. The
family usually stays together until the kits are grown, traveling up and
down the stream or a chain of lakes -- sometimes as much as 10 miles
overland to another body of water -- on a regular circuit that may be
from 15 to 100 miles in length. In deep snow an otter can travel faster
than a man by making a couple of bouncing leaps and then sliding on its
stomach with the legs folded backward.
Apparently, although they have few enemies able to catch and kill them,
otters were never very plentiful nor are they serious predators on fish --
contrary to the belief of most anglers. They were distributed over most
of North America where there were suitable streams and lakes but, even
in Canada and Alaska, the average population seldom exceeded one per
40 square miles. They have been hunted and trapped until extinct or
nearly so in most states except Louisiana and our northern regions. In
1850, according to Robert Kennicott they were not uncommon in Cook
County. There may be a few left in the cypress swamps of southern
Illinois where they were seen as late as 1935.
A striking characteristic of otters, both young and old, is their
playfulness and love of fun. Like rambunctious boys, they will roll,
tumble and chase each other in and out of water, and also play with
objects such as sticks and stones. Even an old female will toss a stone
from paw to paw, roll it on the ground, or toss it in water and then dive
to catch it before it reaches bottom. They love to slide down steep
slopes -- snow or ice in winter; grassy or clay banks in other seasons. A
lone otter, or a whole family, one after another, will coast down a slide
and then climb back up to do it again and again.
animals are "as playful as an otter".
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Update: June 2012