Crab grows garden on its claws

Nature reveals why the yeti crab will never go hungry. It grows methane-based bacterial gardens on its own claws:

The yeti crab — so-called because of the hair-like bristles that cover its arms — is only the second of its family to be discovered. The first — an even hairier species called Kiwa hirsuta — was found in 2005 near Easter Island.

Andrew Thurber, a marine ecologist now at Oregon State University in Corvallis, identified the second species a year later. “It was a big surprise,” he says. “There’s a tonne of them, they’re not small, and they’re six hours off a major port in Costa Rica.”

Thurber had not set out to discover species. He was part of a geological research cruise off the coast of Costa Rica, which aimed to study methane seeps — sites on the ocean floor that belch out methane and hydrogen sulphide gas. While exploring the seep in a submersible, pilot Gavin Eppard noticed the 9-centimetre crabs waving their claws over active seeps, and collected one. “He came up and just handed me this new species,” says Thurber.

The bristles that cover the crab’s claws and body are coated in gardens of symbiotic bacteria, which derive energy from the inorganic gases of the seeps. The crab eats the bacteria, using comb-like mouthparts to harvest them from its bristles.

Heck, they don’t even need sunshine to make food. Chemicals from the sea floor. That’s a survivalist.