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  • Writer's pictureMartha Iserman

Scaly-Foot Gastropod

Chrysomallon squamiferum

AKA: scaly-foot gastropod, scaly-foot snail, sea pangolin, iron snail, volcano snail.

Deja Vú all over again! This is the OG DN. The one that started it all. The most heavy metal member of the invertebrate world. The Scaly-foot gastropod.

I'm back b*tches!

This marine snail lives a hard-core life, residing around the deep sea hypothermal vents of the Indian Ocean at depths of 2,400 to 2,900 meters (1.5-1.8 miles) and 400 degrees Celsius (752 Fahrenheit). This makes it an extremophile, which means it lives in extreme environmental conditions and is pretty bad-ass.

C.squamiferum has only been found in three locations, each creating a variant of the species with unique colorations due to its chemical compositions. What's really crazy, is if you added up the "habitat" of these three locations they'd barely cover 2 football fields.

Each location's species has a different variant with different colorations.

Collect one in every color!

This guy is unique in a variety of ways, the most striking of which is that it is the only species on earth that incorporates metals into its body structure. Both its shells outer layer, and the unique scales on its foot (the soft part of a gastropod body visible outside of the shell) incorporate iron sulphides into their form. These sclerites as they're called look like armoured plating.

And because of these metallic elements they are literally magnetic. You heard that right, you could stick one of these to your fridge.

They create this metallic exoskeleton by taking up iron-sulphide compounds that are created by the extreme temperatures of the vents it lives by, as well as chemicals such as pyrite and gregite. Scientists aren't exactly sure how or why these snails use these chemicals to construct their external anatomy, but many theories are that it helps protect them from predators such as crabs and other snail species. It's a hard core life in the depths, and these snails aren't messing around!

These sulphides that the snail is using are actually extremely toxic, but once the creature mineralizes it and incorporates it into its exoskeleton it's rendered less poisonous. So it's essentially wearing poisonous armor.

So to sum it up; they eat up the toxic chemicals being pumped out of super heated vents in some of the deepest parts of the ocean and turn it into a defensive cover.

Inside the snail, there's even more hard-core weirdness. This guy doesn't eat, at least not in the way we understand eating (like bingeing tortilla chips while watching marathons of MTVs Catfish). It uses a process called chemosynthesis to rely on endosymbiotic bacteria living in its oesophageal gland to provide nutrients. So essentially, instead of filter-feeding in an extreme environment with minimal carbon, it synthesizes the chemicals produced by the vents into a bacteria that can produce nutrients. It makes its own food inside itself.

It's also unusually large for a gastropod with the shells of adult Scaly-foot snails measuring around 32 mm to 45.5 mm. What's more impressive though, is its heart is 4% of its body volume, making it the largest relative to body size in the animal kingdom. So another win for this weirdo.

Because of these unique properties, it's the type species and the sole species within the genus Chrysomallon. This is one unique creature. A Dope Nope one might say!

Unfortunately, since I last wrote about C. squamiferum in 2017 it has been listed as endangered species in the IUCN Red List of Threatened Species. This is due to deep-sea mining and as of 2022 there are no conservation measures in place to protect them. This gives it the unfortunate distinction as being the only species to be listed as endangered due to the effects of deep sea mining.

So pour one out to the original DN!

So what do you think? Is it DOPE? Or a NOPE?

Do you agree on the outcome of the Duck Death Match? Comment with your thoughts!!!


periostracum- a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods.

symbiotroph- An organism that derives nourishment through a symbiotic relationship with another organism.

chemosynthesis-the process by which food (glucose) is made by bacteria using chemicals as the energy source, rather than sunlight. Chemosynthesis occurs around hydrothermal vents and methane seeps in the deep sea where sunlight is absent.

endosymbiont- one organism that lives inside of another one

sclerites-a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth.

oesophageal gland - Oesophageal gland or oesophageal pouch is a part of the digestive system of some gastropods

calcification- the accumulation of calcium salts in a body tissue.

type species- the species on which a genus is based and with which the genus name remains associated during any taxonomic revision.


  • Scaly-foot gastropod. (2022, March 28). In

  • Scaly-Foot Snails. (2019, September 22). Marinebio.Org.

  • Howard, J. (2020, April 7). What is a scaly-foot snail? BBC Science Focus Magazine.

  • Simon, M. (2015, February 13). Absurd Creature of the Week: The Badass Snail That Has a Shell Made of Iron. Wired.

  • Chen, C. (2015, June 18). The heart of a dragon: 3D anatomical reconstruction of the ‘scaly-foot gastropod’ (Mollusca: Gastropoda: Neomphalina) reveals its extraordinary circulatory system - Frontiers in Zoology. BioMed Central.


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