Ian
priscilla 1Greatest Animal Migrations
November 10th 2010 02:22
Animal migration is the travelling of long distances in search of a new habitat. The trigger for the migration may be local climate, local availability of food, or the season of the year. To be counted as a true migration the movement of the animals should be an annual or seasonal occurrence.
The Mother Nature Network (link above) put together 14 of the greatest animal migrations. Below are a few of the biggest.
While many of the world's species of marine mammals migrate, none cover as impressive a distance as the ocean's giant baleen whales.
The gray whale (which travels as far as 14,000 miles round trip annually) and humpback whale (which travels as far as 16,000 miles round trip annually) migrate a greater distance than any other mammal on Earth.
Each species travels to warmer tropical waters during the winter months, where they mate and give birth. Then they swim to the rich colder waters of the Arctic or Antarctic to feed for the summer.
Dragonflies are capable of long-distance migrations, but until recently, scientists had no idea how far they traveled. Last year, scientists discovered a 14,000- to 18,000-kilometer dragonfly migration route that spanned from India to the Maldives, the Seychelles, Mozambique, Uganda and back again.
Incredibly, the epic migration spans four generations for the dragonflies, and each generation plays its part in the journey much like in a relay race. It is easily the longest insect migration ever discovered. The dragonflies appear to follow the rains, from the monsoon season in India to the rainy season in eastern and southern Africa.
Perhaps the most famous animal migration is the journey of Africa's wildebeest herds, which travel annually by the millions in search of greener pastures.
The wildebeest do not travel alone. As many as 200,000 zebra and 500,000 gazelles also make the journey, followed by some of the savanna's top predators. The migration is truly one of nature's grandest spectacles, as the herds perilously cross crocodile-infested rivers while lions prowl in the tall grass nearby.
The ecosystem of Africa's vast savanna could not exist without the migration, meaning that maintaining these habitat corridors is essential to the survival of this area and its creatures.
About 1,800 of the world's bird species are migratory. Some of these journeys are among the longest in the world and bear mentioning here. The world's waterfowl — such as ducks, geese and swans — are symbols of bird migration. Their iconic V-formation as they fly through the sky is recognizable every fall and spring.
The arctic tern (seen here) is tiny but it undertakes nature's longest migration, spanning as many as 44,000 miles annually, as it zigzags the distance between the Arctic and Antarctic. (Sooty shearwaters deserve an honourable mention for making a similar journey.) Seabirds like the albatross spend more of their lives flying than they do at rest, and bar-tailed godwits undertake the longest non-stop flight of any bird, between New Zealand and China.
Penguins also migrate, and they deserve credit for making their incredible journeys through the ocean, rather than through the air.
The annual monarch butterfly migration might be the most colourful migration in the natural world.
Outdistanced only by dragonflies among insects, the monarch migration spans about 7,000 kilometres, covers three to four generations, and occasionally crosses the Atlantic Ocean. It is a spectacular thing to witness.
Populations of the monarchs can be found in Australia and New Zealand, where they are referred to as wanderer butterflies.
*This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia page for Animal migration.
The Mother Nature Network (link above) put together 14 of the greatest animal migrations. Below are a few of the biggest.
Baleen whales
The gray whale (which travels as far as 14,000 miles round trip annually) and humpback whale (which travels as far as 16,000 miles round trip annually) migrate a greater distance than any other mammal on Earth.
Each species travels to warmer tropical waters during the winter months, where they mate and give birth. Then they swim to the rich colder waters of the Arctic or Antarctic to feed for the summer.
Dragonflies
Incredibly, the epic migration spans four generations for the dragonflies, and each generation plays its part in the journey much like in a relay race. It is easily the longest insect migration ever discovered. The dragonflies appear to follow the rains, from the monsoon season in India to the rainy season in eastern and southern Africa.
Wildebeest
The wildebeest do not travel alone. As many as 200,000 zebra and 500,000 gazelles also make the journey, followed by some of the savanna's top predators. The migration is truly one of nature's grandest spectacles, as the herds perilously cross crocodile-infested rivers while lions prowl in the tall grass nearby.
The ecosystem of Africa's vast savanna could not exist without the migration, meaning that maintaining these habitat corridors is essential to the survival of this area and its creatures.
Birds
The arctic tern (seen here) is tiny but it undertakes nature's longest migration, spanning as many as 44,000 miles annually, as it zigzags the distance between the Arctic and Antarctic. (Sooty shearwaters deserve an honourable mention for making a similar journey.) Seabirds like the albatross spend more of their lives flying than they do at rest, and bar-tailed godwits undertake the longest non-stop flight of any bird, between New Zealand and China.
Penguins also migrate, and they deserve credit for making their incredible journeys through the ocean, rather than through the air.
Monarch butterflies
Outdistanced only by dragonflies among insects, the monarch migration spans about 7,000 kilometres, covers three to four generations, and occasionally crosses the Atlantic Ocean. It is a spectacular thing to witness.
Populations of the monarchs can be found in Australia and New Zealand, where they are referred to as wanderer butterflies.
*This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia page for Animal migration.
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