Materials: Drawing paper; colored pencils/markers; internet access
Objective: Students will understand important aspects of the beaver’s life cycle.
Information relevant to the Fur Trade:
Just what was this little animal like that the mountain men chased all over the mountains year after year? The word “beaver” itself comes from an ancient Sanskrit word meaning “big” and “brown.” And they were big at one time, or at least their ancestors were. A million years ago, they were giant six-foot-long, dam-building animals that could weigh 700 pounds!
Today, beavers measure about four feet from nose to tip of tail, and they weigh from 30 to 50 pounds. In the wild, they normally live about twelve years, but tame ones have stayed alive as long as nineteen years. One of the most curious things about beavers is that they keep growing all of their lives!
Beavers live in colonies made up of six to twelve family members, and the whole family joins together to build and repair their dams. The only reason they even build dams is to flood an area with trees nearby so that they can stay in the water and still swim to their favorite food, tree bark. Beavers are built for cutting down trees. They have front paws that can dig and grip, a flat tail that helps prop them up as they eat, and three inch long chisel-like incisor teeth, two on the top and three on the bottom to cut through wood.
After felling a tree, the beaver must then cut it into lengths that are not too heavy to haul by his teeth through the water to his dam. Luckily, the beaver has lips that close tightly behind his teeth so that he doesn’t drown as he tows the logs. He also has transparent eyelids and flaps of skin to seal off his nose and ears when he’s under water. He uses his webbed hind feet to push himself through the water at about five miles per hour, and he has extra-large lungs and liver that allows him to stay under water for fifteen minutes.
Beavers build lodges in their dams to live in. They pile limbs and twigs on top to make a solid pile of brush from five to seven feet tall. Then, they swim up through an underwater tunnel and eat their way into their cozy home. They also make a hole in the top to let in fresh air. Later, they cover the outside with a thick layer of mud, and when it freezes, it gets very hard.
Beavers usually have litters of two to six kits sometime between March and June. The kits weigh less then a pound at birth, and they are so at home in the water that they may follow their mothers into a lake or stream before their first day is over! By the time the kits are two years old, the parents are normally ready to have a second litter, so they run off the two year olds to make room for new babies.
As the young beavers leave home, they try to attract mates so that they can start colonies of their own. They scoop up small piles of earth and then leave a few drops of oil, called castoreum, on them. Castoreum is made in two small oil glands near the beaver’s tail. When other beaver come across the scent, they can tell whether it made by a male or female, and which direction the beaver passed. Once they find mates, they keep the same ones for life.
A normal colony of beavers cuts down over 1,000 trees per year. They eat what they need and then use the rest of wood to build their dams and lodges. When they have taken care of all the trees in one area, they move off to find a new home.
Have students fold a large sheet of drawing paper in half, and on the front page write the title “The Life and Times of the Beaver.” Students may decorate the title page any way they wish.
Instructor will read or have students read aloud the information “A Beaver’s Life” included at the end of this lesson plan.
Have students find pictures of beavers online or in the library.
Students should have a picture of each of the following:
-A prehistoric ancestor of the beaver next to a modern-day beaver.
- A beaver colony eating bark, cutting down trees, dragging them to
the water, or building a dam.
- A beaver lodge.
- A mother beaver taking her kits for a swim.
Have the students paste/tape the pictures they have found on to the two inside pages of “The Life and Times of the Beaver”.
On the back page have the students write the question and answers (are in the information from “A Beaver’s Life”) to the following questions:
Being a beaver, I eat lots of…?
My beaver ancestors could weigh up to this many pounds?
My paws are good for digging, my teeth can cut through the toughest wood, but I use my tail for…?
These two organs are very large in me and that allows me to stay under water for 15 minutes, what are those two organs?
During the winter I’m not very busy and I usually stay in my…?
When we have kits (or babies) there are how many in a litter?
The oil I leave on the ground to attract a mate is called…?
When my whole colony works its hardest, we can cut down more than this number of trees per year…
For your quick reference here are the answers for the above questions:
Help prop me up as I eat and to slap on the water to alert others when I sense danger