What is Rabbits and Wolves?
This game allows the user to simulate how nature keeps its balance and shows how wolves and rabbits
would behave in their natural setting. The general rules of this applet are:
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Two rabbits cannot occupy the same section of grass.
Two wolves cannot occupy the same section of grass.
Each rabbit can only eat grass when he has not reached his maximum food capacity. (The
maximum food capacity can be modified).
A wolf will not eat a rabbit if the rabbit will make him surpass his maximum food capacity. (The
maximum food capacity can be modified).
Rabbits and wolves can only reproduce when they reach a certain age and have a sufficient
amount of food. (The age of reproduction and amount of food required to reproduce can be
modified).
A rabbit cannot reproduce if there is a wolf around her.
Rabbits and wolves can only move up, down, left, or right one space at a time.
Rabbits and wolves die if they get too old or if there is insufficient food. (Maximum age can be
modified).
The grass growth rate is 1. (This growth rate can be modified).
The rules for the births and deaths of rabbits and wolves are a bit more detailed. Let's begin with
rabbits which have the following (adjustable) default parameters:
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Maximum food capacity: 45 units
Metabolism rate: 3 units/stage
Reproduction age: 10 stages
Probability of reproduction in a suitable environment: 50%
Minimum food requirement to reproduce: 40 units
Maximum age: 25 stages
A rabbit gives a food value of 10 to the wolf that eats it.
Using this information, along with the general rules, the computer will determine whether each rabbit
will live, die, or reproduce during each stage.
Wolves have the following (adjustable) default parameters:
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Maximum food capacity: 200 units
Metabolism rate: 2 units/stage
Reproduction age: 10 stages
Probability of reproduction in a suitable environment: 50%
Minimum food requirement to reproduce: 120 units
Maximum age: 50 stages
Using this information, along with the general rules, the computer will determine whether each wolf will
live, die, or reproduce at each stage.
How To Use This Activity:
This activity allows the user to see how wolves and rabbits would behave in their natural setting as an
example of how nature keeps its balance.
Controls and Output:
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The Start Simulation button on the top-left of the applet begins animating the interactions
between the different elements (rabbits, wolves, and the grass) of the grid. It becomes the Pause
Simulation button when pressed. There is also a Step Simulation button in the top-center of the
applet that allows you to see the simulation step by step. (Avoid Step Simulation – it takes too
long!)
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The Pause Simulation button allows you to pause the simulation and look at the current state of
the grid. It becomes the Resume Simulation button when pressed. The Resume Simulation button
allows you to resume the simulation after it has been paused. It becomes the Pause Simulation
button when pressed.
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The Reset Simulation button sets up a new simulation based on the current parameters.
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The Forest Size menu allows you to select the size of the forest. (adjust how you want)
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The Speed scroll bar allows you to speed up and slow down the rate at which the applets displays
the simulation. (Set the speed as fast as it can go!)
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The Forest Border menu allows you to choose between toroid and island. Toroid allows the
rabbits to move off the screen on one edge and wind up on the opposite edge of the forest. Island
does not allow them to move this way.
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The View Population Graph button opens a window that displays a graph of the number of
rabbits, wolves, and grass per iteration.
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In the Population Graph window there is the Display Tabular Data button that allows you to see
the numbers for the last 250 iterations.
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The View Cumulative Stats button allows you to view the population statistics for the current
stage of the simulation.
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The View/Modify Parameters button opens a window that allows you to modify various
settings of the simulation.
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The View Simulation Key button opens a window that displays a legend for the grid.
Questions from the Rabbits and Wolves Game
Go to: www.shodor.org/interactivate/activities/RabbitsAndWolves/ and play around with
the game. Set the speed on fastest it will go. Adjust the parameters as you see fit. Your
ultimate goal is to create a stable ecosystem between the grass, bunnies, and wolves.
1. What affect does a high population of bunnies have on the grass?
2. What affect does a high population of bunnies have on the wolves?
3. What affect does a low population of grass have on bunnies?
4. What affect does a low population of grass have on the wolves?
5. What affect does a low population of wolves have on the bunnies?
6. What affect does a low population of wolves have on the grass?
7. What would happen if there were lots more wolves than there are bunnies? Would the wolves
take over and live forever?
8. What would happen if there were lots more bunnies than there were wolves? Would the
bunnies take over and go on forever?
9. Were you able to create a stable ecosystem between the grass, bunnies, and wolves? If so, list
your parameters:
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Maximum food capacity: Rabbit __________
Wolf ___________
Metabolism rate: Rabbit __________
Wolf ___________
Reproduction age: Rabbit __________
Wolf ___________
Probability of reproduction in a suitable environment: Rabbit ______
Wolf ________
Minimum food requirement to reproduce: Rabbit __________
Wolf ___________
Maximum age: Rabbit __________
Wolf ___________
A rabbit gives a food value of ____ to the wolf that eats it.