General description: Largest of the North American rodents, stocky, with webbed hind feet and broad, flat, scaly tail, ears short, fur thick, rich dark brown. Total length 43 inches; weight from 30 pounds to a maximum of 68 pounds. Tail 4 or 5 inches wide and 12 to 16 inches long.
Where found: Along almost every stream in Yellowstone. They might be seen in the beaver ponds in Willow Park, or along Pelican Creek; or at the beaver ponds and Floating Island Lake between Mammoth and Tower Fall. Longest dam in the park approximately 1000 feet in length is at Beaver Lake opposite Obsidian Cliff. The best time to see beaver is in the evening. Beaver change their locations frequently and it is difficult to predict, from season to season, where they can best be seen.
OTTER
Lutra canadensis
This large member of the weasel family can outswim some fish. His lithe shape and short powerful legs with broad webbed feet make him an expert and his graceful maneuvers in the water are very interesting to see.
The principal item of the Otter’s diet is fish which are supplemented by frogs or crayfish and such young ducks, muskrats or other small mammals or birds as they may have occasion to catch. Their habitat is therefore near suitable streams, lakes or ponds. They have been known, on some occasions, however, to undertake fairly long overland journeys between streams.
The otter is a rather friendly fellow, fairly easily tamed and observed. They usually travel in pairs or family groups. Otters are playful and are in the habit of making slides down steep clay-banks or snowdrifts where they seem to have great sport coasting down on the chest and belly, ending up in the water with a loud splash. This they do over and over like a group of small children.
The den is located near the water, either as a burrow in a bank or under protecting tree roots or rocks. Here the one to three or four young are born in late April, there being only one family a year.
Otters are strong and capable fighters, a match for a dog on land and more than a match for one in the water. They have no particular enemies except man. The rich brown fur has brought a high price on the fur market and trapping operations have resulted in the animal becoming rare outside of such protected areas as Yellowstone. The rather short dense pelt is considered to be one of the most durable of furs and it, together with the layer of fat underlying the skin, make the otter impervious to the icy water in which he spends much of his time.
General description: A long, lithe-bodied animal with webbed feet and a long, tapering, muscular tail. Size large, head broad and flat, legs short. Color of upperparts a uniform, dark, rich, glossy-brown; underparts lighter with a grayish tinge. Total length 40-45 inches, tail 12½ to 15 inches; and weight 18 to 25 pounds.
Terms: Sexes—Male and Female; young—pups or kittens.