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A whale dies in the waters of Monterey Bay off the Northern California coast. Its corpse falls to land with a silent puff in the nearly frozen deep-sea waters of the Monterey Canyon. In the coming months decay and carrion feeders strip the body of most of its meat. After that, its bones become the buffet of a strange, otherworldly genus of worm, that has no mouth, no eyes, no legs, no stomachs, and at first glance, no males. Humans don't know it exists.

That is, until scientists operating the deep-sea ROV Tiburon happen across the whalefall. They're entranced by the worm and bring some back to the ship for study over the next year and a half and finally publish their findings in the 2004 July issue of Science.


Meaning "bone-devourer" in Latin, osedax appears optimized for deep-sea bone-feasting. It has a pinkish stalk from one end of which grows feathery pink plumes that act as gills. The other end, rooted in the bone, balloons out to a puffy whitish ovary sac and light green tendrils. The whole stalk can be withdrawn into a tube in the roots if the worm is disturbed. The worms vary between two and seven centimeters in length.

The scientists identified two species in the genus, namely Osedax rubiplumus (Red-plumed bone-devourer) and Osedax frankpressi (in honor of Frank Press, a former president of the National Academy of Sciences who recently retired from the board of the Research Institute).

The roots of the worm contain symbiotic bacteria, which does the digestion of the oils and fats in the whale marrow.

No males

No visible males, that is. The microscope revealed that each female has dozens of microscopic males living within her, filled with "copious quantities of sperm," but were otherwise larval.

The large number and highly varied sizes of eggs imply a reproduction strategy similar to dandelions, i.e. rapid growth, copious reproduction, and wide dispersal. This is especailly important for the selfish osedax gene since whalefalls are few and far between, and there must be enough spawn drifting in the current to catch the next one.


Osedax's DNA seems to be related to tube worms found at deep-sea hydrothermal vents and cold seeps. Mitochondrial DNA evidence suggests that the genus was a fast opportunist, evolving at the same time whales did, some 42 million years ago.

The genetic diversity of the samples suggests a breeding population of hundreds of thousands, implying a larger whalefall growth medium than presupposed.

Discovering Scientists

in authorship order
Greg Rouse, marine biologist with the South Australian Museum
Shana Goffredi, scientist with Monterey Bay Aquarium Research Institute
Robert Vrijenhoek, scientist with Monterey Bay Aquarium Research Institute

Article also published in Science:
G. W. Rouse, S. K. Goffredi, and R. C. Vrijenhoek, Osedax—bone-eating marine worms with dwarf males. 2004. Science. Vol. 305 #5684 (July 30, 2004).

Biophiliac note

How mind-blowing is the male-female relationship of the genus? Foolishly applying my anthropocentric perspective, I'm amazed that males and females of a species simply might not know about each other. (How would Fundamentalists apply their beloved Natural Fallacy to this one?) The females might think they're living happy lives on whale-carcass Lesbos, while the males ride around in this marvelous Farscapesque spaceship that houses them, feeds them, and all they have to do to keep up their end of the bargain is occasionally jack off onto the hull.

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