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New Worms Eat (and Eat and Eat) Only on Dead Whales

James Owen
for National Geographic News
September 23, 2009
 
Nine new species that dine only on dead whales have been discovered, a new study says. And what the menu lacks in variety it makes up for in portion size—a whale carcass can provide food for 20 years, to be fed on by generations of worms. (See whale pictures.)

The marine worms, which feast on whale carcasses on the seafloor, were collected by remote control subs off the coasts of Sweden and California.

The wriggly scavengers are types of bristle worm (an earthworm relative) that specialize in feeding on bacteria that coat the bones of the decaying giants.

DNA analysis identified the worms as previously unknown species.

(Related pictures: " New 'Green Bomber' Sea Worms Fire Glowing Blobs.")

20-Year-Long Seafood Dinner

Once flesh-eaters like hagfish and sharks have picked clean a whale's skeleton, the 0.8-inch-long (2-centimeter-long) worms go to work, said zoologist Helena Wiklund, a member of the University of Gothenburg team behind the study.

Generations of worms "could be there for maybe 20 years depending on how big the whale was," Wiklund added. "Bones from a big whale last really long on the seafloor."

But when the whale is finally disposed of, the bacteria-munching worms must find another whale carcass, and that could be many miles away.

How the tiny creatures hop from dead whale to dead whale remains a mystery. Some bristle worm species, though, have microscopic larvae that ride ocean currents, Wiklund said.

Whale carcasses "can seep oils for quite a long time, so maybe the larvae sense these smells in the water and then focus in on a new whale," she added.

The new discovery suggests that dead whales may support many other unknown worms, Wiklund said. And some of those undiscovered species may survive the search for their next supersize meal by eating other bacteria elsewhere—around undersea hydrothermal vents, for example.
 

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