Predatory-Prey Relationships: The Fox and the Rabbit game

One goal of this activity is to have students understand how predator-prey interactions affect population size. Students will also analyze data to predict future population sizes. A third goal is for students to explore the major factors that influence the predator-prey relationship.
Key concepts the student should acquire from this activity include how carrying capacity of the environment for the prey population defines the maximum number of prey individuals that can be maintained. They should also see how the reproductive rates of both predator and prey play a crucial role in both population sizes. A third concept students should identify is that behavioral responses of the predators to changes in prey density (migration or change in prey) will affect the pressure on prey.
Before playing this game students should be able to define a food chain, population, immigration, carrying capacity, predator and prey.

I use this activity with a special education inclusion class in 10th grade biology. It can be used in the regular biology classroom, but I would increase the rigor of the game by adding additional predators and other biological factors that can affect populations. This activity is used during a study of populations and ecosystems. The game takes approximately 30 minutes to play. So with an introduction to the game and a closure after the game, I usually allow 45 minutes.

Materials:

-50 10x10 cm tagboard squares of one color (representing the fox)

-200 5x5 cm construction paper squares of another color (representing the rabbits)

-1 50x50 cm square section of table top (the meadow)

-Masking tape (to mark off the meadow)

-Data table

-Graph paper

Rules of the game: You will start the first round with 3 rabbits and 1 fox. The surviving rabbits each produce one offspring for the start of the next round. The fox will survive if it captures (lands on) at least one rabbit, but will only reproduce if it lands on three or more rabbits during one drop in one round. If the fox does not land on any rabbits during a round, it dies, and a new fox will immigrate into the meadow so you will always have at least one fox to start each round. If all the rabbits are captured during a round, three new rabbits will immigrate into the meadow to start the next round. Each round represents one year or a generation.
Procedure:
1.Use masking tape to outline a 50x50 cm square on a flat surface to simulate a meadow in an ecosystem.
2.Randomly distribute 3 rabbit cards in the meadow.
3. Take the fox square and drop it from a height of 10 to 15 cm above the rabbits in an effort to catch a rabbit. (At this point in the activity there is no way that the fox can catch the 3 rabbits that it needs to survive and reproduce. The fox is not allowed to skid and the rabbits should be distributed throughout the field.)
4. Complete the data table for generation #1. The fox will starve if it did not land on a rabbit and there will be no surviving fox or new baby fox.
5. At the beginning of generation #2, double the rabbits left at the end of generation #1. A new fox immigrates into the meadow. Be sure to disperse the rabbits in the meadow.
6.Eventually the rabbit population increases to a level that allows the fox to catch 3 rabbits in a single toss. If the fox catches 3 rabbits it not only survives but it reproduces too! It has one baby fox for each 3 rabbits that it catches. Therefore, if it catches 6 rabbits it will have 2 babies. Fox are not allowed to cheat, but they should try to be efficient. Stupid foxes result in an overabundance of rabbits.
7.As the number of fox increases, throw the tagboard square once for each fox. Record the number of rabbits caught by each fox. The simulation is more realistic if the number of new baby fox is based on each foxes' catch rather than merely the total number of rabbits caught in a generation.
8.There are always at least 3 rabbits at the beginning of a generation. If and when the entire rabbit population is wiped out, then three new rabbits immigrate into the meadow.
9.Remember that the number of rabbits in the meadow needs to be correct at all times. Remove the rabbits caught and add new ones as indicated by your data table.
10.Model about sixteen generations and predict nine more or up to a total of 25 generations. Base the prediction on the pattern observed during the first sixteen generations.
Analysis:
Graph the data for 25 generations. Place both the rabbit and the fox data (the first two columns of the data table) on the same graph so that the interrelationship can be easily observed. Label the vertical axis "Number of Animals" and the horizontal axis "Generations." Use one color of line for rabbits and another color of line for fox.
Resources:
There are many versions of this simulation in use. Other versions include owl and mice, etc. If your students are unable to run the simulation at their own workstations then it may be played on an overhead projector. You may wish to introduce disturbances in the cycle such as killing off the fox or starving the rabbits. This activity serves as a good introduction to computer models. Predator-Prey Simulation Data Table (Microsoft Word 53kB Aug31 08)

Students play the game in groups of three to four.
You could introduce a new predator, such as a wolf, that would require more rabbits for survival, (by using a different color card) to the game as students are playing or after they are finished to see how this new "invader" can affect the population sizes of the existing predator and prey populations.

Students will develop a graph from their data. They will need to analyze their graph to identify limiting factors and carrying capacity of the populations. Also, the graphs will be presented, group by group, to the entire class.

Grade 9-12: IV Life Science: C. Interdependence of Life: 1 Fluctuations in population size and carrying capacity.
Grade 9-12: IV Life Science: C. Interdependence of Life: 2 Explain how adaptation and co-evolution are related to success of an ecosystem.
Grade 9-12: IV Life Science: C. Interdependence of Life: 4 Predict and analyze how changes in an ecosystem affects population and biodiversity of species in the ecosystem.