What is Fuzzy Differential Equation

The concept of fuzzy differential equations is very important for new developments of model in various fields of science and engineering problems in uncertain environments because this theory represent a natural way to modeling dynamical system under uncertain environment. In this way we can modeled mathematical biology problem associated with differential equation in fuzzy environment and solved them. In this chapter we solve two mathematical biology models which are taken in fuzzy environment. A one species prey predator model is considered with fuzzy initial data. Whereas an insect population model are described with fuzzy initial value. The solution procedures of the fuzzy differential equation are taken as extension principle method.