The following differential equations represent the pattern of
interaction between deer, coyotes and wolves in Yellowstone. The
initial amounts are in thousands. It is observed that the increase in
the coyote population increases competition and then causes a
decrease. But the interaction between coyotes and deer has a positive
impact, because there is more food. The equations are:
E1’[t] = 0.04E1[t]-0.003E1[t]C1[t]-0.85E1[t]W1[t]
C1’[t] = -0.06C1[t]+0.001E1[t]C1[t]
W1’[t] = -0.12W1[t]+0.005E1[t]W1[t]