Migration

For the human context, see Human migration mtDNA-based chart of large human migrations. Migration occurs when living things move from one biome to another. In most cases organisms migrate to avoid local shortages of food, usually caused by winter. Animals may also migrate to a certain location to breed, as is the case with some fish. The species that periodically migrate are called migratory, those that do not are called resident (or sedentary). Bird migration is common. The longest ...