Wednesday 9 May 2012

Mini mammoths

In 1904, a famous Natural History Museum collector, Dorothea Bate, collected some teeth from a site in Crete. They were thought to be from a dwarf species of the straight-tusked dwarf elephant genus Palaeoloxodon. The ancestor of the genus, P.antiquus, was a monster, twelve feet tall, but spawned a number of dwarf species dotted around Mediterranean islands. Fossils have been found on Sardinia, Malta, Corsica and Cyprus. The teeth were looked at again recently and a team went out to Crete in search of new material.

It was a successful trip - more fossils were found and the researchers discovered the teeth had belonged to a mammoth rather than its elephant cousin. Mammuthus creticus, a dwarf mammoth - the dwarf bit was correct -  is thought to have evolved from Mammuthus meridionalis, which was trampling around Europe between 2.5 and 0.8 million years ago, or even M.rumanus, an earlier beast. This means the animals might have reached Crete as early as 3.5 million years ago. Maybe on a pedalo.

Island dwarfism is a common phenomenon. Animals have frequently found themselves an isolated new home and shrunk to fit their surroundings. Elephant families have made a habit of it. Aside from all the Mediterranean Palaeoloxodons, dwarf mammoths have been found on the Californian Channel Islands, and Saint Paul Island, while mini-Stegodons have been found on Timor and Flores. The last of the mammoths thought to have lived were not quite a dwarf species, but had shrunk somewhat. They were living on the Siberian Wrangel Island as recently as 4,000 years ago. The island became separated from the mainland around 12,000 years ago, and the native Mammuthus primigenius population gradually got all midgety.

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