Just like human beings, animals’ dwell in places that favor them and in any case, they find it unfavorable, they tend to migrate. So, animal migration is the long-distance movement of animals as a result of changes in the seasons. This movement is common in the major animal groups such as fish, birds, mammals, amphibians, reptiles, and crustaceans.
Animals tend to move due to season change such as when Northern Hemisphere birds move to the South during winter, or due to change in their habitat a good example being when young ones move from their habitat of birth to adult habitat.
Animal migration differs in different species of animals but as a guideline, there are four signs that depict animals are migration. They are;
- Seasonal movement
- Movement in a straight line
- When species relocate on massive scales
- Any movement redistributing members of species in any population
Animals that migrate
There are about 10,000 species of birds in the world and nearly 18% of them migrate as a result of changes in the weather seasons. Most of them are believed to move from north to south. This is because the environment in the summer in the north is conducive for them to feed and breed but given that winter is cold, they tend to move south for warmer climates. Other bird species such as Arctic tern move annually from north to south hemisphere covering nearly 12,000 miles.
Fish tend to stay in water bodies all their lives and therefore, they always don’t migrate over long distances because they only switch habitats over short distances. However, there are distinguished species of fish known to migrate over long distances. Precisely, nearly 120 species of fish such as salmons migrate from freshwater to saltwater habitats. Forage species like herring and capelin move within North Atlantic Ocean and sardines in South Africa.
Winged insects such as butterflies, dragonflies, and locusts are believed to migrate from one place to another. Wandering glider is a species of the dragonfly that makes the longest crossing move among insects, from Africa and moves across the ocean to India.
There are other insects commonly known for migration such as the painted lady and the monarch butterflies but the group that commences the migration is different from the one that completes the journey. If wondering how, the reason is that as they move, they mate and reproduce, and the newer generations complete the migrations.
Mammals are commonly known to migrate from one place to another in search of greener pastures and more conducive environments. A very famous example is the wildebeest migration in Serengeti National Park in Africa.
Other mammal species that migrate are gazelles and zebras and the best thing about mammal migration is that they can change their direction based on the environmental conditions to move towards the rain.
Other animals that migrate include bat species such as the Mexican free-tailed beat; cetaceans such as whales, dolphins, and porpoises; as well as some amphibian and reptile species. Crustaceans such as stunning Christmas Island red crab migrate in large numbers every year.
Why do animals migrate?
As elaborated above, it is evident that different animals migrate from one place to another every year. However, are you wondering why they migrate? If yes, let’s find out.
It goes without saying that animals migrate in search of suitable breeding grounds for reproduction and a good example is the Atlantic salmon. The life of this animal commences in a river and as soon it reaches maturity, it moves to the ocean.
When the time is right for reproduction, this animal goes back to the river and the cycle is repeated. When it comes to crustaceans, many crab species inhabit in deep seas but move to the shallow waters for breeding and then go back to the deeper waters. Amphibians such as toads and frogs live in larger lakes but move to ponds for breeding.
Hibernation and escaping harsh weather
Some animals hibernate during harsh conditions for them to survive. A very good example is the little brown bat that lives in trees during the summer and migrates to caves in the winter for hibernation.
Most species of birds migrate from one place to another when seasons change with Arctic tern being a perfect example. As a result of its migration, Arctic tern experiences two summers yearly instead of one.
Searching for food
Food is the ultimate goal for animal migration. It goes without saying that food is paramount for the survival and when its scarce, animals are likely to die. To avoid death, animals move in search of greener pasture, and a good example is the wildebeest migration in the Serengeti. When food is scarce, these animals move to other places where they are likely to find abundant food.
However, they don’t have a specific place to move to and their direction can change depending on the onset of rains. After moving, they give enough time for the land they left behind to recover so that when they return, they will have enough food. Animals migrate to places with abundant food for reproduction for the offspring to get enough food for survival.
How do animals know which directions to migrate to?
There is no specific science explaining how animals know the direction to migrate to. However, experts have come up with theories that explain this. Firstly, animals use landmarks such as lakes and rivers to tell the direction.
Secondly, other animals use the stars and the sun to determine the directions to move to and thirdly, some animals move with the help of smell and others use the earth’s magnetic field.