Forest Preserve District of Cook County, Illinois
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The Otter
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 swimming.

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 duckling.

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.

Few animals are "as playful as an otter".

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