Figure 14.8 Huffaker’s predator–prey lab experiment. To determine the factors that cause predator–prey cycles, Huffaker manipulated the number and distribution of oranges in a tray filled with oranges and rubber balls. He also added posts that only the prey species were able to climb. The prey drifted from the posts to colonize new oranges. Because the predators had to walk from one orange to another and avoid vaseline barriers, the prey stayed one step ahead of the predators.