Migration is the usually seasonal movement of animals in pursuit of food, suitable breeding sites or to escape bad weather or other environmental conditions. Migrations can be long or short, covering just a few miles to covering half the earth.
Massive animal migrations are arguably one of nature’s most inspiring events. The distance that some species can and will travel on their migration is paralleled only by what they endure to survive. Here are just some of the examples of the world’s greatest migrations.
The migration of the wildebeest
One of the most iconic and famous migration is that of the journey of around 1.5 million wildebeest across the Serengeti/Masai Mara ecosystem, where they migration clockwise. Millions travel each year in search of food. However, it is not so well known that 200,000 zebra and 500,000 gazelles will also make this journey with the wildebeest. Where the prey go, so do the predators follow and lions will be found following the migration.
However, this year, the great wildebeest migration begun three months earlier. Unusually dry conditions in the southern Serengeti encouraged the animals to head north far earlier than usual, heralding the effects of climate change.
The migration of the humpback whales
In the summer, humpbacks are found in high latitude feeding grounds, such as the Gulf of Maine in the Atlantic and Gulf of Alaska in the Pacific. In the winter, they migrate to calving grounds in subtropical or tropical waters, such as the Dominican Republic in the Atlantic and the Hawaiian Islands in the Pacific. The Arabian Sea humpback does not migrate, remaining in tropical waters all year. These amazing creatures migrate further than any mammal. The longest recorded migration was 5,160 miles (8,300 km); this trek from Costa Rica to Antarctica was completed by seven animals, including a calf.
However, humpback whales are threatened by: bycatch, ship strike, whale watch harassment, habitat impacts and harvest.
The migration of the monarch butterflies
Monarch butterflies migrate from the United States to more southernly and westerly areas each autumn to escape the cold weather.
The monarch migration usually starts in about October of each year, but can start earlier if the weather turns cold sooner than that. The monarch butterflies will spend their winter hibernation in Mexico and some parts of Southern California where it is warm all year long. This migration is 2,500 miles long. However, habitat destruction is threatening the species in Mexico and other areas where the butterfly migrates to.
The migration of the salmon
The life cycle of the salmon is treacherous and hard. Females lay their eggs upstream and upon hatching, the young salmon swim downstream. Most die, but the survivors gradually get bigger. Once they reach the sea, after about two years, they set off on a journey of thousands of kilometres to reach their ocean feeding grounds. Here they continue to grow, doubling their weight each year as they feed on smaller fish. When they reach sexual maturity, they return to the freshwater stream of their origin to lay their eggs. Pacific salmon make the round trip only once, but some Atlantic salmon may repeat the cycle several times. With the migration of the salmon, other animals follow including bears.
The migration of the caribou
Caribou, also called reindeer, are found in northern regions of North America, Europe, Asia, and Greenland.
As summer approaches, caribou herds head north in one of the world’s great large-animal migrations. They may travel more than 600 miles (965 kilometers) along well trod annual routes. At the end of their journey, they spend the summer feeding on the abundant grasses and plants of the tundra. The caribou is an important resource for Inupiat Eskimos and Athabascan Indians who live in communities near the migratory routes of the caribou herds.