The worms go in, the worms go out: The habits of prehistoric, bone-eating worms


The fail whale comes to rest; the decomposing body of a gray whale is host to a diverse array of scavengers and other deep sea organisms. From Goffredi et al., 2004.

In the deep sea, no carcass goes to waste. Platoons of crabs, fish, and other scavengers make short work of most of the bodies which come to rest on the sea bottom, but every now and then the carrion-eaters are presented with a rotting bonanza; a whale fall. Muscle, viscera, blubber, and bone; it all gets broken down, but it takes so long that the whale carcass actually provides a temporary home for a variety of organisms which utilize the whale body in different ways. One, a worm called Osedax, actually makes it home within whale bones, and a new study published in the journal Palaios reveals that worms have been doing so for millions of years.


Borings made in the skull of a Pliocene whale. The holes are perpendicular to the surface of the bone, indicated by the dashed line. From Muniz et al, 2010.

The evidence of the habits of the bone-boring worms comes from a 5.3-3.6 million year old partial whale skull found in southeastern Spain. Based upon the small, fossilized invertebrates found in the same layer, it seems the whale settled in water "several tens of meters" deep. Hordes of scavengers would have made the most of the flesh on the whales body soon after it settled, but as its bones became exposed worms began to make their homes in the skeletal architecture.

A series of bore-holes in the back of the whale's skull tell of their presence. Sunk down beneath the surface of the bone were a series of burrows; long scrapes through the bone that look like they could have been made with a hammer and an awl. Anchored into the bone, the worms would then subsist on the lipid content of the skeleton, waving their feathery plumes above the surface of the bone to extract the oxygen they needed to survive.


This hypothesis (restored on the left) is based upon what is seen in the living species Osedax, and though the authors did not find the bodies of the worms they named the peculiar traces they left behind Trypanites ionasi. This is an important distinction. While the holes in the bones are most consistent with the habits of an Osedax-like worm, they may turn out to have been made by a different kind of worm. In this case the identification of the trace fossil, Trypanites ionasi, would remain, but the identity of the trace-maker would be different.

Now that paleontologists have identified these traces, however, they can start looking for them in other whales. Prehistoric whale falls have been identified on the basis of collections of snails, clams, and other organisms around fossil whale bones before, so perhaps the bodies of some of these whales were also home to bone-boring worms. Through such intricate traces, it is possible to envision the life of an age long-past.


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Interestingly enough, the third author (Raul Esperante) is an avowed young earth creationist. If you google his name, you'll see all sorts of crazy creationist bullshit he peddles to the masses.

It seems that he conveniently suppresses all these weird ideas about the fossil record and the "flood" whenever he publishes in a peer reviewed journal. I find it odd that he embraces a young-earth view of the world and geology 6 days a week, but on the 7th day when he goes to submit a scientific paper, he magically uses words like "Pliocene" and "Four million years old".

Normally, it should take more than five minutes on google to find evidence of someone shooting themselves in the foot.

Very interesting. Seriously. Im glad when they discover ancient taxa had the same habits of extant ones. Though here are looking on relatively young fossils, since they are pliocene in epoch

I think likely this kind of scavengers predated on any kind of fall, including mesozoic reptile falls, and any very large animal fall since animals achieved huge size
So we can expect something like plesiosaur falls... or so

I love your blog, Mr. Switek
Really! :)

As Fabrizio mentioned, makes you wonder about similar worms feeding on the carcasses of Mesozoic marine reptiles and giant fish.

Wow that was fast.

I read an article in the Feb. issue of Scientific American today on the ecology of "whale falls" which specifically noted that there is an active search for fossil evidence of Osedax boring into whale bones:

The fossil record [of whale falls] remains rather scant, with data coming almost exclusively from Japan and the Western coast of the U.S. Fossil evidence of Osedax could be especially helpful, given the organism's unique ability to shape the modern communities. Although the lack of a skeleton makes it unlikely that direct evidence of the worm will be found, the borings it makes in whale bones may be recorded in fossils, and many investigative groups are actively searching for them.- Little (2010) "The prolific afterlife of whales", Sci. Am., 302(2):84

I come home surf one of my usual blog stops and poof, there it is.

Interestingly enough, the third author (Raul Esperante) is an avowed young earth creationist. If you google his name, you'll see all sorts of crazy creationist bullshit he peddles to the masses.

Are you sure it's the same person?

By David MarjanoviÄ (not verified) on 31 Mar 2010 #permalink

David -

Yes, this is definitely the same person. He works with Leonard Brand. Just google his name and you'll see all sorts of weird stuff (like dismissing Archaeopteryx as some anomaly having nothing to do with the bird dinosaur transition, etc.).

I tried posting this a couple days ago, but nothing happened.

You'd think that the whale carcass would be found in waters hundreds, thousands of meters deep, not shallow water, cetaceans being mostly open ocean critters. Anoxic conditions. Gills would have a hard time extracting enough oxygen without chemotrophic help.

*pause while I go dig a bit for more info at Wikiworld*

The genus was first discovered in Monterey Bay, California, in February 2002. They were found living in a decaying gray whale in the Monterey Canyon, at a depth of 2,800 m (9,200 ft)'

but then goes on to mention that the genus is also found in very shallow water. Those are very different ocean bottom chemistry environments.

So I went encyclopedia dumpster diving again...

The endo-symbionts are wicked cool and they are highly variable in association, probably depending on the environment the worms are found in at sea. They're intracellular heterotrophic microbes.

They're primitive versions of gut microbes with free-living relatives, but these 'uns are encapsulated within the root organ of these strango worms.

IF you mosey on over to ASM and read the paper

Genetic Diversity and Potential Function of Microbial Symbionts Associated with Newly Discovered Species of Osedax Polychaete Worms. Appl. Environ Microbiol. April 2007, 73(7):2314-2323.

You'll see they found what they think are contaminating genera, probably associated with the outside of the worm, including Episonproteobacteria sp.

They're found in deep-living organisms, in gills (the aforementioned symbiosis I thought might be the case when I saw symbiont mentioned, but this would be an episymbiont, in gills). Interestingly, these bacteria are also found in cow bones. Cow bones were used as an experimental culture medium for our carcass-chawing worm buddies.

'There have also been numerous environmental sequences of Epsilonproteobacteria recovered from hydrothermal vents and cold seep habitats. A member of Bacteria from class Epsilonproteobacteria occurs as endosymbiont of large gills of deep water sea snail Alviniconcha hessleri'.

So you can see why my ears perked right up when I read your blog post. The meat of the story is the bugs, not just the worms.

Better living through bacteria.

Interestingly enough, the third author (Raul Esperante) is an avowed young earth creationist. If you google his name, you'll see all sorts of crazy creationist bullshit he peddles to the masses.

Are you sure it's the same person?