Wild Animals of Yellowstone National Park

by Harold J. Brodrick

The quest for the fur of this little wilderness engineer did more to bring about the exploration of the west than any other one factor. The first daring explorers were continually pushing ever forward into the unknown regions searching for the wealth of furs and establishing the fur trade with the Indians. Thus, the first white man known to have entered the region later known as Yellowstone Park was John Colter, the representative of a fur trader.

These activities greatly depleted the beaver populations but under protection in recent years they have staged a satisfactory recovery in many parts of their former range.

The dams constructed by this animal are well known. Made of sticks, logs and mud, they are a remarkable accomplishment. The dam is for the purpose of impounding a pond of water in which to construct the beaver lodge or house. This also is made of sticks and mud with a room in the middle, above water level, reached by several underwater passages. The pond must be of sufficient depth to provide plenty of water below the level of the winter ice.

Beaver

Sometimes when suitable ponds or still water are available the beaver digs a sloping tunnel into the bank of a stream, with a room at the end and above the high water level.

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.