WILDLIFE IN
RYERSONS WOODS
Beaver
Castor canadensis

Beavers live in colonies in streams and lakes bordered with trees. The Des Plaines River, winding through Ryerson Woods, is an ideal home for the elusive animals. All along the river trails you can see the results of the beavers' work. One beaver at a time tries to fell a tree, gnawing wherever it is handy and letting the tree fall in any direction. Other beavers feed on the fallen leaves and buds or gnaw off branches to build dams or lodges. In the fall, they will secure branches underwater in the mud of the river bottom near their lodge entrance. When winter comes, these stored branches provide food until spring comes.

The animals are active mostly at night from late afternoon to daybreak. They stay in the water most of the time. If alarmed, they may slap the water with their flat tail and dive under; nearby beavers will head for deep water.

Adult beavers are 25" to 30" long not including a 9-12" broad flat tail used for swimming underwater. They weigh 45-60 lbs. Their fur is mainly dark brown with lighter brown fur underneath and black ears, feet and tail.

A beaver lodge is a mound of large bark-stripped branches and logs covered with finer branches and vegetation, and finally, plastered with mud. Usually the top of the lodge is not plastered, to allow for ventilation. It may be located along the shore and over a bank den, or surrounded by water. Each lodge has two tunnel entrances excavated underwater through the mud up into the mound. As the beavers add to the lodge year after year, it may become very large. Lodges are usually 4 by 20 feet, but some have been seen even 40 feet across.

The beavers mate in the water. Both parents, and even some yearlings may remain in the lodge during birth. The young kits are born fully furred and able to walk. In only a couple of days, they will go into the water and by 10 days are able to dive. In 1 to 2 months, they will leave the lodge with their parents. The young beavers are fully grown at 2 1/2 years and in their 3rd spring or summer leave home to stake out a home range, build a dam and lodge, and find a mate.