HOW MANY BEARS CAN LIVE IN OUR FOREST?
indoor / outdoor activity
 

OBJECTIVES

Students will be able to:
1.  Define the term habitat.
2.  Identify one factor that limits a population.

METHOD

Students will become "bears" that will search for one or more component of habitat during this physical activity.

BACKGROUND

This activity is designed to help students understand the 4 components of habitat; food, water, cover, and shelter (a place to raise young).  Key concepts include carrying capacity, survival, and basic needs of wildlife. 

Black bear habitat limits black bear populations.  Because these animals are territorial, meaning that they maintain a set space between them and other black bears nearby, space can be a limiting factor.  Another limiting factor is shelter.  When young bears are two years old, the adult bears send them away to find their own living space.  These wandering young bears are often the ones that people see in their yards and near highways - they will settle down once they find an open area where there is not another bear family. 

When food supplies are limited, bears must compete with each other for food.  Food shortages can happen as a result of weather changes (droughts, floods).  Bears must then look over larger areas to find food, or try to live on the smaller amount of food found in their territory.

All components of habitat are important, but this activity is designed to use food and shelter to help students recognize the importance of suitable habitat. 

MATERIALS

Five colors of construction paper (a few sheets of each color) or poster board. 
One black marker. 
One envelope for each student.  One blindfold.  Pencils. 

PROCEDURE

1.  Make a set of 2" x 2" cards from the colored paper for a group of 31-35 students.  Make 30 cards of each of the five colors to represent food as follows:

ORANGE = nuts (acorns, pecans, walnuts, hickory nuts); mark five pieces N-20, mark 25 pieces N-10.

BLUE = berries and fruit (blackberries, elderberries, raspberries, wild cherries); mark five pieces B-20, mark 25 pieces B-10.

YELLOW = insects (grub worms, larvae, ants, termites); mark five pieces I-12, mark 25 pieces I-6.

RED = meat (mice, rodents, peccaries, beaver, muskrats, young deer); mark 5 pieces M-8, mark 25 pieces M-4.

GREEN = plants (leaves, grasses, herbs); mark five pieces P-20, mark 25 pieces P-10.

The numbers above equal pounds of each food.

There should be less than 80 pounds of food per student so that there is not enough "food" in the forest for all the bears to survive.  You can also add water to the activity, by cutting out 50 squares of light blue paper.

If you have a group of more or less than 31-35 students, you may use this chart to help determine how many cards to make.

# of Students:

10-15

16-20

21-25

26-30

31-35

36-40

41-45

Nuts (N-20)
Berries (B-20)
Insects (I-12)
Meat (M-8)
Plants (P-20)

2

3

3

4

5

6

7

Nuts (N-10)
Berries (B-10)
Insects (I-6)
Meat (M-4)
Plants (P-10)

8

13

17

21

25

29

33

2.  In a large, open area, scatter the colored pieces of paper. 

3.  Give each student an envelope and have them write their name on it.

4.  Have students stand on a 'starting line' with the envelopes on the ground between their feet.  This is their 'den site' and should be left on the ground.  Other ideas for den sites could be small plastic containers or bowls, clothes pins, etc. 

Tell students, "You are now black bears.  All bears are not alike, just as each one of us is not exactly alike.  One of you will be the young male bear that has not been able to find his own territory.  Because he is tired, he will have to hop on one leg to hunt.  (Assign one student to be this bear.)  Another bear is a young female that got to close to a porcupine and whose eyes were injured.  She cannot see very well.  (Assign one student to be this bear and wear the blindfold.)  A third bear is a mother bear with two cubs.  She must gather twice as much food as the other bears.  (Assign one student as the mother bear.)

5.  Students are not to be told what the colors, initials, and numbers on the colored paper represent.  They can be told that the different colors represent different kinds of food (and water).  Since bears are omnivores (eating a variety of foods), they should gather different colored squares.

6.  Students then should walk into "our forest."  Bears do not run down their food, but gather it.  Students pick up food one piece at a time and return it to their 'den' before picking up another square of paper.  (Bears would not return to their den to eat, they would eat it where they found it.)

7.  When all of the colored squares have been gathered, the students pick up their envelopes and return to the classroom.

8.  Explain what the colors and numbers mean.  (Each color is a kind of food and the numbers are pounds of food eaten.)  Each student should total up the number of pounds he or she has gathered.  Students should write the total number on the outside of their envelopes.

9.  Using a chalkboard, ask the three special bears (young male, young female, and mother bear) how much food they found.  Write this on the board.  Then have each student report their numbers and write this on the board as well.  Tell students that each bear needs 80 pounds of food to survive.  Which bears survived?  Was there enough food to feed all the bears?  Did the mother bear get 160 pounds of food?  If she had eaten first, would her cubs have survived?  Will each of the special bears survive? 

10.  If there were water squares, each student needed to pick up 1 water square to survive.  Water is often a limiting factor and an essential component of habitat.

For higher level students:

11.  Have students record how many pounds of each of the five categories of food he or she gathered.  Have each student convert this number to a percentage of the total food they gathered.  Compare these percentages to the following table that represents actual data from a bear population in Arizona.  Ask the students how healthy they think their bears would be, based upon these needs.  Did their bears have a balanced, nutritious diet?

nuts 20 pounds = 25%

berries and fruit

20 pounds = 25%

insects

12 pounds = 15%

meat

8 pounds = 10%

plants

20 pounds = 25%

TOTAL

80 pounds = 100%

12.  Students can calculate a class total for all the pounds of food they gathered as bears.  Divide this number by 80 pounds needed for a single bear to survive a 10-day time period.  How many bears would this habitat support?  Why did only  bears survive when the class gathered food?  What percentage of bears survived?  If the food had been evenly divided, what percentage of bears would have survived?  In each case, what percentage of bears did not survive?  What limiting factors (natural and cultural) would be likely to influence the survival of individual bears and populations of bears in an area.

EVALUATION

1.  Define "limiting factor."  Describe some of the factors that limit survival of an animal that lives in your area.

2.  Have students invent an indoor game to demonstrate limiting factors for wildlife.

3.  Have students explain how this relates to human populations.  What are our "limiting factors?" 

 



 
Alabama Black Bear Alliance © 2006