Mutant Planet

Top 10 Extinct Species
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No. 10 - Steller's Sea Cow

Land cows eat grass, but these "sea cows" once grazed on kelp in the Bering Sea.

A relative of the smaller, much-beleaguered manatee, the gentle sea cows were over 25 feet long and may have weighed as much as 10 tons.

By the time German naturalist Georg Steller found and described them in 1741, their population was already threatened, perhaps due to hunting by indigenous peoples.

Their extermination would quickly continue with the arrival of Alaska-bound European fishermen and seal hunters. The sea cows were rapidly hunted for food, skins (used to make boats) and oil (for lamps), and by 1768, less than 30 years after Steller found them, the Steller's sea cow was extinct.