Lotka–Volterra equations

The Lotka-Volterra equations are two equations that scientists use to describe how two different kinds of animals interact in nature. For example, the equations can be used to show how the number of lions and zebras in a certain area might change over time. In the equations, one variable (called x) stands for how many lions there are, and the other variable (called y) stands for how many zebra there are. The equations predict how x and y will change in the future, depending on how many lions and zebras there are now.