These 'Hyper Nasty' Clams Live in Chimneys Made of Their Own Poop

Nature is beautiful and wondrous and sometimes really gross.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
2 min read
A funky looking piece of wet wood with tons of tiny clams that have bored into it.

This piece of Douglas fir spent two years in the ocean and was bored into by poop-dwelling clams.

Janet Voight

Dwelling in your own filth might not sound like an appealing lifestyle, but a species of wood-eating ocean clams has found a way to make it work. A study published in Marine Biodiversity on Thursday delves into the cruddy secret lives of pea-size clams from the Xylophaga dorsalis branch of mollusks. 

The clams use their shells to bore into wood under water. Most similar clam species have two long tubelike siphons, one for pulling in clean water and one for expelling waste well away from their bodies. "But in these related hyper-nasty borers, the siphon for expelling de-oxygenated water and feces is short; it stays inside the borehole in the wood," said lead author Janet Voight in a statement. As the researcher puts it, "they poop in their borehole."

A person holds out their hand with fingers covered in crumbled up bits of wood that has been bored by ocean clams.
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A person holds out their hand with fingers covered in crumbled up bits of wood that has been bored by ocean clams.

Crumbly wood brought up from the ocean got that way thanks to the work of some clams that bored holes and pooped all around themselves.

Kate Golembiewski/Field Museum

Voight is a zoologist and mollusk specialist with the Field Museum in Chicago. The study looked into a mysterious trend found in clam-bored ocean wood: Some wood pieces remained structurally intact, but others crumbled easily in researchers' hands. A closer looked revealed the "poop chimney" clams were responsible for the weak wood. 

The study looked at clam-bored wood specimens from around the world. Researchers deploy pieces of wood into the ocean so they can study creatures like these clams. One of the samples mentioned in the study spent two years under the waves and reemerged looking very chewed up by the poo-party clams. 

The clams don't seem to mind their crappy surroundings, and might even use the poop as a signal for others of their kind to come hang out in their wood abodes. "It sure isn't very hygienic, and yet they show no evidence of immune problems," said Voight. "They're healthy, they're clearly going to town on the wood. So why did they evolve this way?"

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These particular clams are tough little critters. So even if a lot of their own species show up, use up available oxygen and make their living environments even poopier, they still thrive. This is thanks to special adaptations, including a substance in their blood that lets them pick up more oxygen. They can survive in low-oxygen environments that would sicken their kin. That means less competition from other sea creatures.     

The clams aren't trying to be gross. "They don't do it on purpose, their anatomy makes them do it," said Voight. It just so happens that their anatomical quirks also help them live their best lives. 

I hope this study spawns a new phrase: Happy as a clam in a poop chimney.