In climatic regions where winter occurs, there are two options for a species to survive; migrate or overwinter. Mosquitoes are not migratory; they all overwinter on the breeding grounds in one life stage or another. This stage varies widely depending on the type of mosquito and the location. In mild climates, mosquitoes may overwinter as eggs in water or moist soil, or as larvae or pupae in water. In colder climates, where water and soil freeze, mosquitoes typically overwinter as mated adult females, which go dormant in animal burrows and other sheltered places. It's not truly hibernation; only mammals do that. The adult males die because they mate only once and have no further purpose.