Crabs left the sea not once, but several times, in their evolution
Most terrestrial plants and animals departed the ocean for land only once in their distant past
![A photo of a land crab in the Cook Islands](jpg/111323_ah_crab-revolution_featb14e.jpg)
Crabs, such as this one from the Cook Islands, have colonized nearly every type of habitat on Earth, popping up everywhere from deep-sea hydrothermal vents to steamy mountainside jungles.
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