Part 8

The beaver is a gnawing animal equipped with strong, sharp, chisel-like teeth which it uses to cut down and trim the trees for construction material for the house and dam as well as for food. Expert at cutting down the trees but not as expert, as stories say, in dropping the tree in a desired spot. This is not premeditated. The tree falls where it may and has been known to fall on the little sawyer when he failed to move away fast enough. The tree, after being cut, is trimmed into suitable sections and skidded to the pond and floated to the desired location. The trees and shrubs preferred and mainly cut are willow and aspen.

The beaver’s winter diet consists of bark from the tree branches that it stores up by sticking them into the mud at the bottom of the pond. In the summer the bark diet is supplemented by the addition of roots and green vegetation.

The four to six young are born in the house or the bank den in May or June where they remain until able to make the underwater swim to the outside where they soon assist their parents in the work of the colony.

The beaver is equipped with a large flat paddle-like tail. However, contrary to stories, he does not use it as a trowel or as a means of transporting mud. It is an excellent rudder and also a prop or brace for the owner while he stands up to cut down a tree. The resounding slap of the tail upon the surface of the pond is an excellent warning signal that immediately puts the colony on guard.

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.

Where found: They are active all of the year and are found on many streams and lakes throughout the park. Best seen near the outlet of Lewis Lake and near the boat docks at Lake and West Thumb. Active at all hours.

WESTERN MINK Mustela vison energumenos

The mink is a large weasel of slightly heavier build and semi-aquatic in habit. Found widely distributed in forests or on plains but always along watercourses where it establishes its den. This may be a burrow in the bank, under logs or rocks and similar places.

They are strong and graceful swimmers and are fully capable of catching trout and other fish which form a part of their diet, as well as frogs and crayfish. They also hunt on shore for muskrats, mice, rabbits, snakes, birds and similar forms of small animal life. The mink is sometimes of bloodthirsty temperament, killing for the pleasure, but is not ordinarily considered quite as much inclined this way as the smaller weasels.

The odor of the musk carried by the mink as well as the other weasels is strong and very offensive. This is released in moments of excitement.

The mink has but one litter of young a year, numbering five or six in the average litter, which are born in April or May.

General description: A slender weasel-like animal nearly as large as a house cat. Ears small, neck long, tail moderately bushy. The fur is soft and dense, protected by long guard hairs, rich, glossy dark sooty brown in color with a white area under the chin. Total length 24 inches, tail 8 inches; weight up to 2 pounds, the females somewhat smaller.

Where found: Along some of the streams and ponds of the park but not very common and seldom seen.

ROCKY MOUNTAIN PINE MARTEN Martes caurina origenes

This little animal is close kin to the famous Russian Sable and has a valuable pelt or rich, dense fur. Expert climbers, they hunt through the woods and capture a good portion of their menu from the tree tops. Largely carnivorous the marten lives on small mammals and birds. Its main foods in Yellowstone are squirrels, chipmunks, mice, rabbits, grouse, and also some nuts, berries, fruits, insects or honey.

Fearless and pugnacious they frequently quarrel among themselves and do not hesitate to snarl or spit at man. One time a ranger was standing in front of a patrol cabin when a marten came bounding toward him spitting and snarling at every jump. To see what he would do the ranger made for the cabin door and the marten came right after him even to the cabin door. It was decided that they would be pretty tough to live with if they suddenly became as big as bears with an increase in disposition accordingly. A marten family quarrel sounds like a good cross section of an alley-cat serenade. Being extremely active they are able to elude most would-be enemies except possibly the Great Horned Owl.

The marten nest is usually in a hollow tree or rarely in a burrow, where the young, averaging 3 or 4 to a litter, are born late in April. It is said that the young are blind for about the four weeks after birth.

General description: A small animal, of weasel-like form, a little smaller and more slender than a house cat; head rather small with ears broad and rounded, tail bushy and cylindrical, about half as long as the head and body. Fur soft, rich yellowish brown; legs, feet and tail dark brown; buffy patches on throat and chest. Total length 25 to 28 inches, weight 1½ to 4 pounds. Males largest.

Where found: Fairly common throughout wooded sections of the park but are shy and seldom seen, especially near habitations except isolated cabins where they sometimes become rather tame.