Various reasons for animal migration

Animal migration refers to the migration of a large number of animals over a certain distance due to breeding, foraging, climate change and other reasons. There are regular migration and irregular migration. Main reasons:

1, copy. In order to reproduce better, they migrated. For example, large-scale migration of salmon in North America and Russia.

Step 2 feed. In order to meet the needs of survival, they had to migrate. For example, the great migration of wildebeests in East Africa.

3. Migration caused by seasonal changes, such as changes in temperature and vegetation, so Yannan flew to seek a good living environment.

4. Migration caused by major natural disasters. Natural disasters refer to natural phenomena that endanger human survival or destroy human living environment, including meteorological disasters such as drought, high temperature, low temperature, cold wave, floods and flash floods.

Extended data:

Fish periodically migrate in a certain direction due to factors such as season, reproduction and foraging, which can be divided into:

(1) Reproductive migration. For example, eels in fresh water areas swim to the deep sea to lay eggs during the reproductive period, which is called long-distance migration.

(2) Juvenile fish migrate, that is, fish living in the ocean swim to fresh water to lay eggs during the breeding period, and the hatched juvenile fish swim to the ocean with the melting of ice and snow in the following spring.

(3) Foraging and migration, in which fish migrate to prey-rich waters in groups to feed on plankton.

(4) Seasonal migration, that is, due to seasonal changes in seawater temperature, fish migrate to waters with suitable temperature.

Some migratory birds return to their breeding grounds every spring and move to the southern wintering grounds in autumn for seasonal and breeding reasons, and migrate periodically along a certain route in the horizontal direction. The migration route of each bird is unchanged, usually along the food-rich near water; Take North America as an example, there are four main migration paths for birds:

(1) Pacific migration route, the route along the Pacific Ocean along the west coast of the American continent.

(2) the Mississippi route, along the Mississippi River migration.

(3) The central migration route is along the Rocky Mountains.

(4) Atlantic route, along the east coast of the American continent near the Atlantic Ocean.

Migration brings many benefits to birds, mainly in:

1 make birds always live in the most suitable climate, and the food sources are rich and diverse, which is conducive to maintaining their vigorous metabolism;

Migration can also create the most suitable conditions for raising offspring, because raising offspring requires a lot of food;

In the north, eggs can hatch the most, with long seasons and rich days, so parents can have full opportunities to collect food;

There are few enemies in the north, and the appearance of this annual fragile juvenile black will not promote the formation of enemy population;

Migration can greatly expand the space for activities and is conducive to reproduction and occupation;

6. It is beneficial to automatic balance, which can avoid climate disparity in aviary;

7? Migration provides opportunities for birds to spread to new distribution areas and for different individuals to contact and mate, so it is also of great significance in evolution.

References:

Baidu Encyclopedia-Migration