BUSY AS A BEAVER!
Grades K - 5

The beaver is a North American animal that protects itself by being a builder. Beavers build dams that create ponds. The water of the pond surrounds the beaver lodge and this is protection from predators for the beaver. A great variety of animals are attracted to the beaver ponds, but humans do not always like the work of the beavers--especially when their ponds and dams cause floods. In this video lesson, students will learn about the physical characteristics of beavers and will see how they construct their dams and lodges. They will learn that a beaver dam can raise the water level of a pond by a meter or more. The follow-up activities will deal with measurement in inches and centimeters of pictures of the various BBP s--Beaver Body Parts. The lesson should take about 45 minutes.

World of Nature, #1--Beavers: Builders or Destroyers

Students will be able to:

• compare and contrast the different ways that beavers and humans change the countryside
• recognize and label the major physical characteristics of a beaver
• list some specific ways that a beaver contributes to the wetland environment
• list some specific ways that a beaver destroys the environment
• demonstrate an awareness of the relative size of the different body parts of a beaver

• lesson outline chart
• Beaver Measurement Cards (one set of three cards for every two students)
• rules with inches and centimeters (one for every child)
• worksheet 1--BUSY AS A BEAVER! Pretest
• worksheet 2--Beaver Measurement Recording Sheet
• worksheet 3--How Many Words Can You Make Out of B-E-A-V-E-R?
• worksheet 4--Beaver Statistics for Teachers (one for the teacher, optional for students)
• worksheet 5--Beaver-Chewed Trees recording sheet
• worksheets 6 and 7--Beaver-Chewed Log patterns

In preparation for this lesson, the teacher should make a lesson outline chart that will be taped to the top of the television screen and hang in front. Students can look at the chart while the teacher is introducing the lesson. The chart should have the name of the lesson, Busy as a Beaver! at the top and then say, Beavers--Builders or Destroyers? This is the title of the video and the springboard topic for the previewing discussion. Two additional questions should be posted on the chart and discussed:

• WHY and HOW do beavers change the countryside?
• WHY and HOW do humans change the countryside?

To give students a specific responsibility while viewing, tell them to look for these Beaver Body Parts listed in the Previewing Activity. Tell them you will be stopping the video at various points to see if they are good BBP detectives by playing a mind-reading game. You will ask them this question each time you stop the video, I m thinking about a beaver ________. The students will be expected to fill in the blank. Explain that they will need to watch very carefully to be able to read your mind.

START the video at the beginning. The narrator will say, There are two animals that change the countryside to build their homes--humans and beavers.

PAUSE video when the narrator says, When the beaver changes the countryside, animals appear. Brainstorm a list of animals that students think would appear when a beaver changes the countryside by building a dam. Tell them that when you resume play they will see some animals that come to a beaver pond and then later in the video they will see more. Each time they see an animal on their list, they can give themselves a silent thumbs up. Tell them to also try to read your mind in the next segment. Explain to students that at the pause point you will say, I m thinking about a beaver ________. If they are good detectives, they will know what body part you are thinking about. Clue: A beaver swims, but it does not quack.

RESUME video. You will see animals that do appear when a beaver changes the countryside--the kingfisher, the great blue heron, and the ruddy duck.

PAUSE when you hear The entrance is underwater so they can enter and exit without being seen. You will see a close shot of the webbed hind foot of a beaver. Say, I m thinking about a beaver ________. When you snap, all students should say the word to fill in the blank. Ask the students to observe the hind foot and then explain how it is different from their own. Why does a beaver need a different kind of hind foot? Tell the students that a beaver s hind foot has five long, webbed toes. To give students a focus for the next segment, tell them to watch closely when you stop the video and see if they can read your mind and name the body part you are thinking of. Clue: This body part acts like the rudder on a boat when the beaver is swimming.

RESUME video and you will hear the narrator say, Inside it is dry and cozy.

PAUSE right after the narrator says, Beavers live in close family groups . . . You will see a family group inside a lodge, and it is a good place to take a close look at the beaver tails. Say, I m thinking about a beaver ________. Ask students why they think the beaver needs such a large, flat tail. Tell students that when a beaver swims, it uses its tail to steer. They also slap their tail on the water to warn other beavers of possible danger and use their tail as an extra support when standing on their hind legs. Direct students to look at the beavers on the screen. They will be able to see how small the eyes and ears of the beaver are. Tell them that beavers have a transparent inner eyelid that covers and protects their eyes so they can see underwater. How lucky beavers are to have built-in goggles! Clue for the upcoming BBP: The beaver uses this body part very much like a human.

RESUME video as the narrator continues, . . . last year s babies or kits and this year s kits.

PAUSE after the narrator says, They can hold food with their hand-like front paw while they chew. Say, I m thinking about a beaver ________. This is a good, close view of a front paw. Ask students to compare the front paws of a beaver to the hands of a human. Ask students to list tasks that a beaver might be able to do with its front paws. Clue for the upcoming BBP: Beavers are very vain.

RESUME video and you will see the beaver combing his fur. The narrator continues, Besides eating, beavers spend a lot of time grooming their coats.

PAUSE when the narrator says, They spread a light body oil throughout their fur to keep it waterproof. Say, I m thinking of a beaver ________. The nails on the webbed hind foot look very sharp. Students will not have seen the cleft toe nails, but they will know that the beaver used the nails to comb his fur. Tell students that the beavers comb their fur with two split nails on each hind foot. Clue for the next BBP: The beaver uses these instead of an ax.

RESUME video. You will now see a beaver in the water building a dam and the narrator says, Once their lodge is built it s time to build the dam.

PAUSE video just after you hear, With its large sharp teeth the beaver can chew through trees. Say, I m thinking of beaver ________. You will see the four very large, front orange teeth. Ask the children why the beaver has such big front teeth. Tell the children that actually the beaver has 20 teeth--10 in each jaw. The four front teeth are used for gnawing and they are called incisors. These front teeth continue to grow throughout a beaver s life and they need to gnaw continually to keep the teeth from getting too long. Use this opportunity to tell students that the beaver has two flaps of skin behind those protruding front teeth that seal off the back of its mouth while the beaver is gnawing and working in the water. Tell them that in the next segment they will see what the beaver does with those teeth.

RESUME video as the narrator says, It cuts off the young upper branches of the tree for the dam.

PAUSE when the narrator says, . . . has built a pond that other animals can enjoy. To give the students a specific responsibility for viewing the next segment, remind students to look for animals on their list.

RESUME video and you will see amphibians (frogs and tadpoles), newts and salamanders, birds (92 different kinds of birds have been spotted at beaver ponds including the flicker, the warbler, the hairy woodpecker, the American goldfinch, and the spotted sandpiper). At the end of the segment, students will see a moose, elk, and deer.

STOP video when the narrator says, Only one animal doesn t like the pond--humans. Discuss briefly why man sometimes doesn t like a beaver pond.

Review with the students the various Beaver Body Parts observed in the video--fore legs, hind legs, teeth, eyes, ears, nose, cleft toe nail, and the flat tail. Talk briefly about the beaver s fur and how the beaver uses the cleft toe nail to comb oil through its fur. This helps the beaver to be waterproof. Help the students to understand that even though the beaver makes its home in the water, it is a mammal just like them. It has made special adaptations to live in the water.

The math follow-up activity for this lesson is called MEASURING BEAVER ANATOMY. During the video students were given the opportunity to take an up-close look at the different Beaver Body Parts--BBP s. Now students will use their measuring skills to record the length and width of three major parts of the beaver anatomy--the tail, a front foot which is almost like a hand, and a webbed hind foot. Discuss with the students the way the beaver uses its flat tail to steer it through the water and to slap it on the water to scare away enemies. Look at the picture of the beaver s front foot and discuss the various ways it might use the hand-like foot to help in building a dam or lodge. Discuss the webbed hind foot. Ask students to think of other animals with webbed feet and discuss the reason for the webbing.

Before handing out the measurement worksheets, use a yard stick to help children understand the real size of a beaver. A beaver may grow to be three or four feet long and weigh between 40 and 95 pounds. This is just about the size of many first and second graders. Tell students that the drawings of the beaver body parts that are on the worksheets are not the actual size of a real beaver s tail, front foot, or hind foot, but that the drawings look like the real thing. Explain that they are just using the drawings to practice their measuring skills. Pass out the measurement sheets and the recording sheet. Have the students work with their partners to determine the height and width of each body part. If the students are first graders, you may want them to measure using unifix cubes. Second graders can measure to the half inch, and older students can measure in inches and centimeters. Students will then record their measurements on the measurement worksheet.

NOTE: A beaver tail is flat and wide and is covered with black, scaly skin. It is 12 to 18 inches long and about 6 inches wide. The beaver tail on the measurement worksheet is about half that size. As an enrichment activity, students could be challenged to try to draw a beaver tail to scale.

Contact your local Audubon Society or a local conservation or science center. Check to see if they have any outreach programs about wetland habitats.

Contact your state Environmental Services Department. Arrange for a speaker to come to the classroom from the Water Resources Division.

Take the students on a field trip to a near-by beaver pond. Observe firsthand the changes in the land that they can see.

Language Arts: How Many Words Can You Make Out of B-E-A-V-E-R? After showing the video, pair students with a partner. These partners will do this activity together. Give each pair a copy of worksheet 3--How Many Words Can You Make Out of B-E- A-V-E-R? Give students five minutes to do this activity and then share the words. Make sure you tell the students to be as Busy as a Beaver while filling out the worksheet.

Math: Beaver-Chewed Logs This activity can be done in the classroom using the beaver-chewed logs on worksheets 6 and 7 or students can be taken on a field trip to a beaver pond where they would measure real beaver- chewed trees. Each pair of students will need a ruler, a pencil, and the Beaver-Chewed Trees recording sheet (worksheet 5). If you are doing this in the classroom, you will want to make a set of Beaver-Chewed Logs (worksheets 6 and 7) for each pair of students. Run the masters off on brown construction paper and put each set in a small manilla envelope. Whether doing this activity in the classroom or in the field, student pairs work together to measure the beaver- chewed trees and record their answers. Tell students to make sure they write the word inches after each measurement.


Science: Experiments Which Prove Beavers Have an Amazing Anatomy Note: Before beginning, have students sit in a big circle and place a large pan of water in the center of the circle.

1. Beavers are mammals like we are, but they are especially adapted for life in the water. Beavers breathe air like all mammals do, but how can they do that while swimming under water?
BEAVERS CAN T BREATHE UNDER WATER, SO THEY MUST HOLD THEIR BREATH.
THEIR HEART RATE SLOWS WHEN THEY DIVE, SO THEY USE UP OXYGEN MORE SLOWLY THAN WHEN THEY ARE OUT OF WATER.

Experiment: Use stopwatch and time student volunteers as they hold their breath. BEAVER AMAZING ANATOMY FACT: BEAVERS CAN SWIM SUBMERGED FOR A HALF MILE.
THEY CAN STAY UNDER WATER FOR AT LEAST 15 MINUTES (LENGTH OF MORNING RECESS) OR 900 SECONDS!

2. Do beavers wear bathing suits?
BEAVERS ARE WARM-BLOODED.
THEY CAN FEEL COLD JUST AS WE HUMANS DO. WE PUT ON CLOTHES TO KEEP WARM.
HOW DO BEAVERS KEEP WARM IN THE COLD WATERS OF THEIR POND?
THEIR TWO FUR COATS, AN OUTER AND INNER COAT, HELP, BUT THERE IS SOMETHING ELSE.
LET S FIND OUT.

Experiment: Do an oiled-paper experiment. Wrap a piece of tissue inside an oiled piece of newspaper that is carefully folded around the tissue. Wrap another piece of tissue inside an un-oiled piece of newspaper. Submerge both in the pan of water. Observe carefully as the paper packages sit in the water (if students watch closely they might see air bubbles coming from the un-oiled package). Remove simultaneously and unwrap. Ideally, oiled paper should keep its tissue dry!
BEAVER AMAZING ANATOMY FACT: BEAVER FUR IS NOT ONLY VERY THICK (ESPECIALLY THE INNER COAT CLOSEST TO ITS BODY), BUT THE OUTER LONGER HAIRS ARE OILED BY THE BEAVER TO WATERPROOF THEM.
BEAVERS TAKE OIL (CASTORIUM) FROM A GLAND AT THE BASE OF THEIR TAIL AND USE THE CLEFT-NAILS ON THEIR HIND WEBBED FEET TO COMB IT THROUGH THEIR HAIR.

3. Why does a beaver have such a wide, flat tail?
A BEAVER SLAPS ITS TAIL ON THE WATER S SURFACE TO WARN THE REST OF THE COLONY ABOUT DANGER.
IT IS ALSO USED AS A RUDDER WHEN THE BEAVER IS SWIMMING AND IT HELPS THE BEAVER BALANCE WHEN STANDING UP ON ITS HIND FEET TO GNAW DOWN TREES.

Experiment: Start by slapping a piece of yarn and then a piece of thin wire on the surface of the pond. Have students note the differences. Then continue slapping wider objects on the water working up to a broad beaver tail-shaped piece of leather.


Art: Papier-mache Beaver Make a life-sized papier-mache beaver. Before making the beaver, draw the outline of a life- sized beaver on chart paper. Divide the class into research groups. Give each group a beaver body part to research. The results are recorded on the beaver outline in the area of the body part researched.

Brainstorm with students the materials that will be needed to make the papier-mache beaver: assorted sizes of brown paper bags, newspapers, medium-sized rock, masking tape, string, papier-mache paste, straws, black yarn, brown tissue paper, brown acrylic covering. Get suggestions and support from your art teacher.

Select paper bag size necessary to each body part and fill with newspapers. Place the rock at the base of the main body part to stabilize. Squeeze and tape into appropriate sizes and shapes. Use straws for fingers and toes. Tape all parts to the main body and cover with the brown tissue paper strips covered with paste and finally with the brown acrylic covering.


Resources
Dabcovich, Lydia. Busy Beavers. New York: Scholastic Inc., 1988.

Katz, Sue and Associates, Inc. and Steven Low Productions, Inc. Beavers. New York:
Scholastic Inc., 1995.

Leagjeld, Ted. Chip the Beaver: Builder of Minnesota Lakes. Brainerd, Minnesota: Bang
Press, 1972.

Lepthien, Emilie U. A New True Book of Beavers. Chicago: Childrens Press, 1992.

MacDonald, Amy. Little Beaver and the Echo. New York: The Trumpet Club, 1990.

Master Teacher: Judy Handley
Beaver Meadow School, Concord, NH