Entries in crabs (2)


Science Club Round-Up

A collection of this weeks Science Club articles, all brought together in one easy to read place.


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Great Migrations of the Animal Kingdom: Part Three

In the third and final part of this week’s look at incredible animal journeys, it is today the turn of those down to earth creatures with their feet firmly on the ground, as Frontier considers terrestrial migrations of the animal world.

Wildebeest - Southern Serengei (Tanzania) to Masai Mara (Kenya)

No feature on great animal migrations could be complete without looking at this amazing spectacle made famous by countless natural history documentaries and wildlife photographers. Everyone is familiar with images of this mass movement, which often focus on the various predators gorging themselves as the millions of wildebeest make their annual voyage.

The migration begins in the lush, short grasses of the southern Serengeti, where the herds gather in November. It is here that the animals calve, giving birth to their young at the beginning of February. The heard remain in this location until around April, leaving only when the calves have gained enough strength for the journey ahead. This period sees many predators taking advantage of the vulnerable calves. As the long rains move westwards through the central Serengeti, the wildebeest head north-west in search of the fresh pastures these rains bring. This brings them into the Western corridor and towards the Grumeti River, the crossing of which in June brings about the herd's first contact with the well-documented crocodiles lying in wait for their arrival. July sees the drying of the grasslands, forcing the herds to move north in search of food. The wildebeest will face another croc-infested river crossing as they head for the grasses of the Masai Mara throughout August and September. After grazing in the lush Mara grasslands, the herds eventually begin to move south again during late October and November. A final crossing of the perilous Mara River is made en route to the southern short-grass plains of the southern-Serengeti where the cycle begins once more.        

Christmas Island Red Crabs – Forest to Coast

Despite their association with the sea, the annual migration of red crabs on Christmas Island is very much a terrestrial affair. Like all of the migrations covered in this feature, this must be an incredible thing to witness. At some point during October and November, approximately 120 million adult red crabs begin an amazing journey from the forests in which they normally reside. Streams of crabs must climb down steep inland cliffs to reach their destination. Having reached the coast, these adult crabs mate and release eggs into the sea. Each female lays approximately 120,000 fertilized eggs. After about a month in the sea, the eggs develop through various larval stages, before eventually forming into tiny crabs. The surviving individuals then move onto land and begin their journey back to the island’s inland forest.

By Alex Prior