Predators must eat prey to survive, they have long lives and small populations.
Prey must avoid predators to survive, they eat plants, are short-lived and have large populations.
Below there's a visual that shows the dynamic relation between both populations. A red pixel represents an area dominated by predators, blue by prey, and purple is a mix of both. The darker the pixel, the more animals there are in the area. The total population proportions are represented by the two bars at the bottom.
Under map options, there are four presets you can choose from that show this dynamic in different scenarios. If you want to make your own, feel free to edit the variables or paint on the map with the "Predators", "Prey", and "Background" buttons yourself. Once done, press play to watch the scenario unfold.
If you edit a scenario yourself, you may notice that it's difficult to find an equilibrium where one of the groups doesn't disappear. But don't worry, nature itself wasn't balanced in a day.
Death Age - The age at which the animal will die, each frame/cycle adds 1 to all animal's ages
Birth Age - The minimum age at which an animal can produce an offspring
Birth Energy - The amount of energy an animal uses to produce an offspring, also the amount of energy the offspring begins with
Max / Pixel - The maximum density of a species allowed in a single pixel
Max Penalty - The energy penalty given to an animal if they are in a pixel above the maximum density
Passive Energy - Energy change for each frame/cycle, prey gain energy and predators lose energy
Predation Energy - The amount of energy gained by a predator when they predate on a prey