• The simulation requires regular, numbered UNO cards (or any
numbered cards) with a range of five consecutive numbers
Each prey–predator combination requires 60 cards (50 prey,
Each simulation requires spare cards of the higher numbers in the sequence (e.g., 4 and 5) for constructing subsequent generations.
• We provide students with tables for data entry and accompanying worksheets for all data summaries and calculations.
• Students provide writing utensils and calculators.
Laboratory sections of our introductory biology course, Principles of
Zoology, hold 20–30 students, whom we divide into five or six
prey–predator combinations. Each prey–predator group receives
an envelope with numbered cards presorted into prey and predators.
Each card represents an individual. Each number represents its flying, running, or swimming speed. Card-number frequency distributions overlap between prey and predators (e.g., Table 1). Prey
outnumber predators in a 5:1 ratio. We label envelopes to represent
real-world prey–predator scenarios such as (1) gazelle vs. cheetah,
(2) snowshoe hare vs. Canada lynx, (3) fur seal vs. white shark,
(4) eastern cottontail vs. ermine, (5) mallard vs. peregrine falcon,
and (6) blue sheep vs. snow leopard.
Rules of Play
1. Starting with the provided cards, prey and predator teams
calculate the beginning mean and standard error of running
speed for their populations (Table 1).
2. Each team shuffles its cards and places them in a pile face
down between itself and the opposing team.
3. Play begins as the prey team turns over the first five cards
while the predator team turns over one card.
4. The outcome of each interaction depends on the relative
speeds of prey vs. predator.
a. Prey with an equal or higher speed ( i.e., card number)
than the opposing predator outrun that predator and
escape to contribute to the next generation.
i. Prey win ties based on the rationale that predators must both catch and subdue prey, giving
equally fast prey an advantage (this oversimplifies
reality but provides a framework for simulation).
b. Predators subdue all opposing prey with lower speeds.
c. Each predator must subdue at least two prey to avoid
starvation and contribute to the next generation.
i. This modification of Tatina (2007) provides
increased “realism” because
(1) A predator does not have to subdue every
prey it encounters to survive.
(2) A predator that ultimately starves can still
subdue some prey.
5. Teams retain cards of survivors to determine the next
6. Teams discard cards of subdued prey or starved predators.
7. The game continues with each team revealing its cards five
prey to one predator at a time until all interactions are decided.
8. We assume that all survivors are reproductive equals. Thus,
each team simulates reproduction by rebuilding the population to the original carrying capacity of 50 prey or 10
predators based on the proportions of each speed ( i.e., card
number) that survived (Table 2).
Table 1. Example starting card distribution for a
prey–predator group with starting means and
standard errors of card numbers ( i.e., running
speeds). Card numbers can be any consecutive
sequence of five.
Team 1 Card
(Prey): Number of
Number of Cards
Total card count 50 10
Mean ± SE 5 ± 0.2 5 ± 0.4
Table 2. Example first-round results for predator
group based on a simulation using the starting card
distribution in Table 1. Calculation of the next
predator generation is illustrated.
10 5 10
Mean ± SE 5.0 ± 0.37 – 5.6 ± 0.34