Origins of the Hairy-Chested 'Hoff' Crab: Evolution in the Deep Ocean (Video)

In depths of the ocean, a hairy crab named after David Hasselhoff thrives. The "Hoff" lives around hydrothermal vents, existing in an area of extremes. Now, scientists have discovered the evolutionary history of this crab, finding out that they're far from being the ancient "relics" that researchers once believed.

Hoff crabs are actually named for their "hairy" chests, which are actually composed of setae. A type of yeti crab, this creature was first discovered in 2011. Its life history and behavior is still largely unknown, but researchers have found out a few things about these crabs. They live over 6,500 feet beneath the ocean waves next to hydrothermal vents that spew fluid at temperatures greater than 662 degrees Fahrenheit. With little light and oxygen available to them, these crabs feed by "farming" bacteria on their hairy chests. They then use specialized mouthparts to comb off the bacteria for food.

While you'd think that this crab wouldn't be able to move very far from its original location, researchers believe otherwise. The new study actually suggests that the crabs take advantage of the Antarctic Circumpolar Current (ACC), a current which flows in a clockwise direction around Antarctica through the Drake Passage. It's likely that the crab actually originated around the vents that populate the mid-ocean ridges in the eastern Pacific Ocean before expanding with the aid of this current.

"We suspect their [larvae] dispersal capability may be limited," said Christopher Roterman, one of the researchers, in an interview with BBC News.  "The fact they have spread so quickly in the Southern Ocean is because the ACC provides a high-speed highway for their larvae. But when they head further north, we think they may have a disadvantage against other hydrogen vent animals."

In order to learn a bit more about this crab, scientists analyzed the DNA of yeti crabs--including the Hoff crabs. They found that, surprisingly, these creatures began to diversify and expand 40 million years ago. That's far closer to the present than the scientists expected to find. Many thought that animals living around volcanic vents were relic species, largely unaffected by environmental changes on land and the shallower parts of the ocean. Yet these new findings seem to show otherwise.

"The life of these charismatic crustaceans is a delicate balancing act," said Nicolai Roterman, one of the researchers, in a news release. "They exist in the narrow zone where the water from the vents and normal seawater mixes, their challenge is to position themselves close enough to the vents to thrive but not so close that they risk suffocating or getting cooked alive."

In fact, the low oxygen means that if levels fell further, it's likely that the crabs wouldn't be able to survive. As ocean conditions change, these deep sea crabs may be in danger.

The findings are published in the journal Proceedings of the Royal Society B.

Want to see the crabs in action? Check out the video below, courtesy of YouTube.