The carcasses of dead whales don't last long on the ocean floor, thanks to colonies of ravenous worms that feast on their bones. Now, U.S. researchers have figured out how the worms devour the massive bones without any teeth, mouth, or even a gut.

It turns out the delicate, flower-like Osedax worms, which range in size from a few millimeters to barely longer than a human finger, have "massive acid-secreting capacity," reported researchers at Scripps Institution of Oceanography at the University of California San Diego in a paper published recently in the journal Proceedings of the Royal Society B.

That acid helps the worms bore into the bones of the whale, dissolving away the calcium phosphate that makes them hard and impenetrable and providing access to a more palatable part of the bone — a protein called collagen.

Martin Tresguerres, a marine biologist from The Scripps Institution who was the lead author of the paper, said it's likely the worm then absorbs the collagen through its skin.

A close-up of an osedax worm shows part of it buried in a whale bone. That part is called the root and it secretes the acid to dissolve the bone. (Greg Rouse)

"We haven't seen any other way in which they can absorb nutrients," said Tresguerres in an interview with Quirks & Quarks that airs Saturday.

He added that this method of eating "might seem a little strange," but is likely not too different from the way humans absorb nutrients through the wall of their intestine.

Interestingly, the way the worm eats is very similar to the way bone is dissolved inside the bodies of healthy mammals as part of normal skeletal repair and remodeling, the researchers said.

Tresguerres said before the discovery of the worms in 2002, scientists estimated it would take up to 30 years for a whale carcass to completely decompose in the ocean. However, the bone-eating worms may be able to complete the gargantuan task in less than 10 years.

He added, "They're probably very significant players in the recycling of organic matter in the ocean."