Origins of Hairy-chested "Hoff" Crab Reveal Insight into History of Global Warming

Deep below the ocean surface lives a hairy-chested crab whose origins researchers have revealed for the first time.

Despite its seemingly remote location down around the hydrothermal vents found in the Southern and Indian Ocean, the maroon Yeti crabs (Kiwaidae) are, in evolutionary terms, relative newcomers that diversified approximately 40 million years ago, according to a study published in the journal Proceedings of the Royal Society B.

These "Hoff" crabs, nicknamed after the frequently bare-chested actor David Hasselhoff, have yet to be scientifically described and probably represent two separate species, split off from their hairy-clawed Yeti cousins. At the time they split, the crab traveled east from the Pacific via an ocean super-highway as the Drake Passage, located between South America and Antarctica.

Their environment, meanwhile, is one of the most extreme on the planet.  Found some 6,500 feet (2000 meters) deep, the crabs seem to enjoy the extreme heat and noxious chemicals released by the volcanic vents it calls home.

And while food can be scarce on the ocean floor, the creature feeds by effectively "farming" bacteria caught in its chest hair using a special comb-like mouth.

Despite such hardiness, however, new research by scientists at the University of Shouthampton and Oxford University as well as the British Antarctic Survey manifests an Achilles heel: changes in oxygen levels caused by global warming.

According to Nicolai Roterman of Oxford University's Department of Zoology who led the research, the crab's life is a "delicate balancing act."

"They need oxygen to survive, in short supply around the vents, but the bacteria they 'farm' for food depend on chemicals only available near the vents," he explained 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."

There was once a time when scientists remained blissfully unaware that the effects of climate change could affect even deep-sea creatures living around the ocean's floor. However, with more and more examples such as the Hoff crab emerging, it's becoming clear that most of those who dwell in such regions date back a mere 55 million years or so, with previous inhabitants having gone extinct long ago.

While the reasons for this are unclear, a period of intense global warming spanning several million years that also started 55 million years ago and dramatically reduced deep-sea oxygen levels may be to blame, the researchers speculate.

Should current trends in global weather changes, the Yeti crabs will face the challenging choice of suffocating or starving as circulation between the well oxygenated surface waters and those deeper down likely decline. However, if history is to repeat itself, then the loss of the crab and its neighbors will, eventually, be replaced by a new wave of species once conditions become favorable again.