FOXES AND RABBITS - PREDATOR/PREY SIMULATION GAME
Mary Lee
(adapted from LAB ACTIVITY - Predator-Prey Simulation: Population Growth by
Neil Sheard, Sarah Donnelly, Colleen Rapaich)
Objectives:
To investigate how populations are affected by predator-prey relationships over
several generations.
Materials:
- Sixty, 6cm x 6cm squares cut from stiff coloured paper: the foxes.
- 400, 2cm x 2 cm squares cut from a different color of paper: rabbits.
- One sheet of green paper (approx. 43 x 28 cm): the meadow
- Graph Paper
Rules:
The game contains a meadow and stacks of reserve cards for foxes and rabbits, active
foxes and rabbits are taken from this reserve. The meadow is the playing field.
To start the game, the rabbit managers distribute three rabbits evenly on each
meadow. The rabbit managers add active rabbits by spreading them evenly in the
meadow and remove rabbits when they are caught.
The fox managers throw active fox cards and add or remove active foxes from the
meadow.
All animals that are removed from the meadow are placed back in the reserve stacks.
The following represents one round of the game and produces one generation:
The fox managers toss each active fox square into the meadow to try to catch rabbits.
The fox manager's hand must remain outside the meadow area. As long as the fox
square touches a rabbit square, that rabbit is deemed to be caught.
Each fox that can catch three rabbits with one toss has enough energy to reproduce, so
the fox managers double the surviving fox population in the next round.
After the caught rabbits are removed, the remaining rabbit population is doubled for
the next round.
If a fox cannot catch three rabbits in a round, the fox starves and is removed from the
meadow by the fox managers.
If there are no surviving rabbits, a new round is begun with three new rabbits, which
immigrate into the meadow.
If there are no surviving foxes, a new round is begun with a new fox, which
immigrates into the meadow, and double the number of rabbits left at the end of last
round.
Play the game in groups of four. Work in pairs. One pair manages the prey (rabbit
population), and the other pair manages the predators (fox population).
Begin the game with one fox and three rabbits. Record these numbers as rabbits and
foxes in the meadow. Continue to record their counts at the beginning of each round
for the 25 generations in the game.
One of the fox managers should toss a fox card into the meadow in an attempt to land
on at least three rabbits. Probably, the first fox catches fewer than three rabbits and
starves. There will be no surviving fox or new baby fox. (How do you explain this?)
The rabbit managers should double the rabbit population and place them in the
meadow.
Complete the data table for this generation.
The fox managers too, add a new fox into the meadow.
If the fox catches three rabbits, remove three rabbits, add a fox, and double the
remaining rabbits for the next round. If the fox was unsuccessful, begin the next
round with a new immigrant fox, and continue to double the remaining rabbits.
Continue additional rounds. Eventually, the rabbit population will increase to a level
that allows the fox to catch three rabbits in a single throw. If the fox catches three
rabbits, it not only survives but also reproduces. It has one baby fox for each three
rabbits that it catches. Therefore if it catches six rabbits, it will have two babies.
Continue to play the game for up to 25 generations, recording data at the beginning of
each generation. By this time your meadow may be full of rabbits. Throw as many
fox cards as are in their populations.
Interpretations:
1. Graph your data using the number of individuals as the dependant variable
(vertical axis) and the number of generations as the independent variable (horizontal
axis). Us a separate line on the same page for rabbits and foxes.
2. Study your graph lines for the two populations. How are the fox and rabbit
populations related to each other? How do the sizes of each population affect each
other?
3. Under what modifications can both populations continue to exist indefinitely?
4. What do you think would happen if you introduced an additional predator, such as
a hawk, which requires fewer rabbits to reproduce?
5. What would happen if you introduced another type of rabbit, one that could run
faster and escape its predators? (In the game, you could give the new type of rabbit a
chance to escape by tossing a coin after it is caught and letting it live if you got
heads.) Which type of rabbit would predominate after many generations of
predation?
Applications:
1. How does this simulation relate to the human population and its interaction with its
environment? Are there any predator-prey relationships?
2. What predator-prey relationships have you observed in your community?
3. If a population biologist visited your classroom, what are some questions about the
human population you could ask?