Birds do it. Fish and mammals do it, even insects and reptiles do it. Animals across the globe fly, swim or walk in their effort to find food or a more hospitable climate or places to breed. To be counted as a true migration, the movement of the animals should be an annual or seasonal occurrence. Migrants can use the sun, the stars, reflected light, the Earth’s magnetic field and their sense of smell to find their way.
The longest migration record is held by a bird, the Arctic terns, weighing in at less than 4.5 ounces (125 grams), flying around 25,000 miles (40,000 kilometers) from their Arctic breeding grounds to the Antarctic and back. But a few years ago, researchers fitted birds with miniature geolocators and discovered that some of them traveled more than 50,000 miles (80,000 km) in a year because of the meandering routes they took to exploit prevailing wind systems!
Also famous in birds world, the Alaskan bar-tailed godwit, which apparently makes its eight-day, 6,835-mile autumn migration (11,000 km) from Alaska to New Zealand in one step, with no stopovers to rest or refuel!
The longest migration made by a land mammal is that of the caribou, which can travel 3,000 miles annually, in North America!
In Africa, migrating wildebeest know there’s strength in numbers. They travel close to 1000 miles in a herd of over 1.5 million individuals, along with hundreds of thousands of zebra and gazelles, between Kenya and Tanzania.
On the other hand, the world’s largest mammal migration (in terms of numbers of individuals) occurs every October through December, when up to 10 million straw-coloured fruit bats migrate from the Congo to Zambia’s Kasanka National Park.
According to Guinness World Records, the leatherback sea turtle holds the record for the longest migration of any reptile. Astoundingly, a tagged turtle reportedly took 647 days to travel from its nesting site on the beaches of Papua, Indonesia, to its feeding grounds off the coast of Oregon in the United States.
Salmon fishes have one of most impressive migratory power in animal kingdom, they traverse between freshwater and saltwater. After hatching of eggs salmons remain in river waters for 2-3 years. During that time salmons undergo many physiological changes. These changes help them to migrate to seas waters without facing much obstacles. For next 3-4 years they prefer to live within salt water. Reproductive capacity within this species of fish will develop during that time. Then they migrate back to fresh water, the exact river where they born, return to home for spawning. The exceptional navigation power itself help salmons to make their return journey from saltwater to freshwater, their brain can detect exact magnetic field of their birth place. Their ability in jumping and sense of smell also help them during their extreme migration, will cover up to 3800 kilometers in a complete migration. You could then truly say the salmon’s live is one long migration route, with few preparation and transformation stages!
Demoiselle cranes have to take one of the toughest migrations in the world. In late August through September, they gather in flocks of up to 400 individuals and prepare for their flight to their winter range. During their migratory flight south reaching altitudes of 16,000–26,000 feet (4,900–7,900 metres), and along their arduous journey they have to cross the world’s highest mountains (Himalaya) to get to their over-wintering grounds in India.
Like nomadic humans, animals migrate because it’s often difficult to survive if you remain in the same place all year long. By moving from one place to another, these animals also give their environments time to rebound as well. Food supplies are often more plentiful when the animals return after a long absence. Migrations may be one way that ecosystems keep themselves in balance.
Migrations are the true animal kingdom marathons and triathlons, proving one more time that each living individual is a survivor and a champion of its specie, each year betting their lives on it, whereas in human world only few take lower scale equivalent of long distance body and mind endurance challenges! This is one extra reason for all humans to respect wildlife and try to learn from, and to assure the survival of these champion species in a natural unspoiled environment, and a continuity of their migratory way of life, saving their most important spots for feeding and breeding along these essential for survival migratory routes!
World’s most amazing migrations images HERE, and their amazing record keepers, by CNN. And a great book to read: Where the Animals Go, Tracking Wildlife with Technology in 50 Maps and Graphics! Enjoy!