Many people associate migrations almost exclusively with birds. In particular, many Americans have come to know and loathe Canadian geese, which migrate in huge numbers … and leave an enormous amount of droppings in their wake. Luckily, other migrations in the animal kingdom aren’t as messy and annoying for humans. In fact, many are quite spectacular, drawing tourists to the plains of Africa, on Pacific cruises and elsewhere to take in these spectacles. Here’s a look at some of the most epic animal migrations, several of which scientists are still trying to understand.
5. Porcupine Caribou
The porcupine caribou native to Alaska and Western Canada migrates more than 3,000 miles annually — the longest migration of any land mammal in the world. That migration pattern caused serious concerns during planning for the Trans-Alaska Pipeline, as environmentalists feared the pipeline would disrupt migration routes. To alleviate those fears, engineers added more than 500 elevated 10-foot-high sections of pipeline, and buried the pipeline in a couple of dozen other spots, to facilitate the migrations. In recent years, advocates of these caribou have vigorously opposed drilling in the Arctic National Wildlife Refuge, the caribou’s calving grounds.
4. Pacific Salmon
No creature faces more potential obstacles during its migration than the Pacific salmon as they journey from their longtime home in the ocean to their freshwater spawning grounds. They must swim upstream, and jump through special “fish ladders” past hydroelectric dams. They must somehow get past waterfalls and rapids. Salmon, which are very sensitive to water quality, often must swim through polluted urban waters. Predators such as eagles and bears are always lurking. Not surprisingly, most salmon do not survive the journey to spawn. Those who do face yet one more challenge in the spawning grounds, as males battle for the favor of females, and females fight for a place to nest.
3. Humpback Whale
Brought back from the edge of extinction in the mid-20th century, these whales usually migrate up to 15,000 miles a year, from their winter home in polar waters to their summer breeding grounds in equatorial regions. These migrations are big attractions, as charter boats carry tourists hoping to catch a glimpse of these whales breaching the surface in a spectacular display.
A subspecies of the antelope, wildebeest roam the African plains by the millions. Some types of wildebeest remain in a relatively narrow home range, but certain wildebeest are known for their large-scale migrations. Wildebeest on the Serengeti plains in Africa will migrate more than 1,000 miles during the dry season in search of water and greener grasslands. In the process, the 1.5 million migrating wildebeest create the equivalent of a moving buffet for lions, crocodiles and other predators of the savanna. Because of the wildebeest’s large size and the enormous numbers in the migration— which also include zebras and other interlopers — wildebeest provide the most visually spectacular migration on Earth. A number of travel companies offer tours that take in the migrations, as well as visits to other nearby sites such as Olduvai Gorge and Ngorongoro Crater.
1. Arctic Tern
The Arctic tern is not an impressive bird in appearance, mostly gray and white with a wingspan of just more than 2 feet. But what they lack in appearance they make up for in stamina, as they are by the far the most prolific migrators in the animal kingdom. Scientists who tagged certain terns were once amazed to find they had migrated from Canada to South Africa in a few months. But more recent tracking efforts show that some terns travel more than 50,000 miles annually, taking a zigzagging course between the Arctic and Antarctica and back again.
That begs an obvious question: Why do Arctic terns migrate so far? Well, they follow their bizarre course — which sees them fly from Antarctica, to Africa, then to South America, then back to Greenland — to take advantage of prevailing winds. As for why they cover such a wide range, they’re after waters rich in fish.
One More: Green Sea Turtle
Found in tropical oceans around the world, the green sea turtle can cover tremendous distances over open water, moving between its feeding grounds and hatching beaches. In the process, it displays an uncanny sense of direction and ability to travel these routes in virtually a straight line. For example, the green sea turtles that inhabit the Brazilian coast migrate to nesting grounds on Ascension Island, a relatively tiny speck some 1,500 miles away in the Atlantic Ocean. How is that possible? The scientific consensus is that the turtles use the Earth’s magnetic field to guide their course. However, researchers in one study stuck magnets on some of these turtles to disrupt their magnetic sense, and the turtles still found their way to Ascension.