Knight Ridder Newspapers

MONTEREY, Calif. – Things can get pretty hairy down at the bottom of the sea.

Crabs, for instance.

Not hairy-as-in-scary. Hairy-as-in-hirsute.

Scientists – including marine biologists from the Monterey Bay Aquarium Research Institute in Moss Landing – have discovered a new species of crabs that they’ve named “hirsuta” because of their very hairy legs.

But big hair isn’t all these crabs have going for them. They’re also blind, smelly, and endowed with many intriguing traits – evident to scientists if not to the rest of us – that set them apart, far apart, from any other crabs that anyone has ever seen.

In fact, researchers believe that what they found isn’t just a new species, or even just a new genus, but a whole new family of crabs.

In the basic hierarchy of animal names, species is the lowest rung, genus is next and family is the third step up. So finding a new species is a big deal, finding a new genus is a bigger deal, and finding a new family is even bigger.

Scientists first laid eyes on these creatures a year ago when they were snooping around the ocean floor about 900 miles south of Easter Island and more than a mile below the Pacific Ocean’s surface.

Which explains why nobody had ever run across them before.

“This is the furthest south that any human-occupied submersible vehicle has ever gone,” said Joe Jones of MBARI, who was one of the humans who occupied the submersible vehicle Alvin during the expedition.

People don’t jump at the chance to venture into that area because, weatherwise, “It’s a horrible region to be in on a ship,” Jones said.

In other words, things could have been hairy-as-in-scary for the researchers. But they lucked out and had calm seas for the five weeks they were there.

They hadn’t gone looking for weird crabs. They had gone to study all sorts of animal life around hydrothermal vents, which are sort of like geysers under the ocean.

Geological surveys had predicted they would find vents in the area, which they did. Finding the hairy crabs was a lucky bonus.

“The Alvin has a very small window to look out of, about four inches in diameter,” Jones said. “You get a very narrow view of what’s down there.”

And yet, on any one dive, researchers saw between five and 10 of the crabs – which seems to imply that the place might be crawling with them.

“As soon as we went a little further north though, we didn’t see them any more,” Jones said. “We might have been on the edge of their distribution.”

A typical dive lasted seven or eight hours – long hours.

“You’re in this little sphere, it’s really cold, and you really have to use the bathroom,” Jones said. “But you have to put all that aside and do your job.”

The “little sphere” that is Alvin holds a pilot and two researchers. When the researchers see something they want to collect – e.g., an odd-looking crab – the pilot uses a “slurp gun” to “vacuum up” the specimen.

But first he has to set Alvin down on the ocean floor, and that can have unfortunate consequences for any animals it happens to land on.

Unfortunate consequences for mussels, however, might be fortuitous for hairy crabs.

“We saw them getting little pieces of mussels that got broken,” Jones said.

That provided one of the few facts that researchers know about hairy crabs: They can eat the tissue of other animals.

But researchers speculate that the crabs may also eat certain bacteria. At least, large colonies of bacteria live on the crabs’ hairs, and it’s possible that the crabs “grow” these colonies for food.

Researchers saw crabs stretching their claws over the outskirts of vents, perhaps because the bacteria thrive in the warm, gaseous water coming up there.

“The crabs could graze off the bacteria,” Jones said. But that’s just one hypothesis. “Really, it’s sort of a mystery what they do.”

Much about the crabs is a mystery. But their bad smell is perfectly understandable. The water coming from hydrothermal vents is full of hydrogen sulfide, which smells like rotten eggs.

“Any animal that lives around the vents usually smells pretty foul,” Jones said. “Everything we bring up smells bad. Pretty soon the whole ship smells bad.”

The researchers only brought up one hairy crab, a male, and that “slurpee” didn’t survive, most likely because he had been under such a lot of pressure all his life.

About 33 feet of water equals one “atmosphere” of pressure – the amount that all the air in the atmosphere weighs down something at sea level.

Hairy crabs live under about 7,200 feet of water, or about 220 atmospheres of pressure. So coming to the surface gave him the crab equivalent of a fatal case of the bends.

In a way, though, the crab has become immortal because he’s now a “holotype” – the single specimen used to describe his kind.

Holotypes lead to random results, of course. For example, this hairy crab was about six inches long.

But from looking at video of the dive, Jones said, “It turns out he’s a small one. It looks like we got a baby.”

They got him about a year ago, but the world is just hearing about him now. Jones called that time frame “sort of normal for finding a species.”

The researchers had to finish the Easter Island expedition, and then another. Then they had to write a paper, which took time. Then the paper had to be reviewed, which took more time. Only then could it finally be published.

One of the big revelations in the paper is the hairy crab’s name, or names. Its scientific name – genus and species – is Kiwa hirsuta, where Kiwa is the Polynesian goddess of shellfish. Its family name is Kiwaidae, again in honor of Kiwa.

More affectionately, the hairy crab is called the Yeti crab, after the hairy abominable snowman that’s sort of the Bigfoot of the Himalayas.

Some in the media have given it yet another name – “hairy lobster” – but that’s a mistake. Jones explained how it happened: The Kiwaidae are closely related to another family of crabs, which are called “squat lobsters,” even though they’re crabs, not lobsters. Some picked up on the “squat lobster” part, but missed out on the “crabs, not lobsters” part.

The holotype of the hairy crab – aka the Yeti crab, aka Kiwa hirsuta – now has some lovely new digs in the French National History Museum, which displays a large collection of deep-sea crabs. Jones thinks that’s a positive development.

“It gives me a reason to go to Paris,” he said.