This document summarizes a simulation created using STELLA to model the relationship between palm oil production and rat and owl populations. It introduces STELLA as a tool for constructing dynamics models of biological systems. The simulation shows palm oil production depends on rat and owl populations, with rats preying on palm plants and owls preying on rats. The normal graph shows an equilibrium between the three variables, but the abnormal graph shows palm production decreasing as rat numbers rise with no owl predation. Manipulating the owl population affects the rat population trend.