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10 of the biggest animals to roam the planet

By: Katherine Butler on May 20, 2011, 12:25 p.m.
The claw of the Jaekelopterus rhenaniae was 18 inches long.

Photo: Biology Letters

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A haunting creepy-crawly

Afraid of bugs? Then this creature might make an appearance in your nightmares. The giant sea scorpion, otherwise known as Jaekelopterus rhenaniae, is thought to have been 8 feet tall. It lived about 400 million years ago. Experts say the giant sea scorpion may have evolved to such a large size in an "evolutionary arms race" with armored fish. Some experts say this long-extinct creature was a predecessor to modern-day land scorpions.