Overview
The Scaly-foot Snail (Chrysomallon squamiferum), commonly termed the ‘sea pangolin’ or volcano snail, is an extraordinary peltospirid gastropod that survives in one of the most hostile environments on Earth. Clinging to the scalding, mineral-rich chimney walls of abyssal hydrothermal vents in the Indian Ocean, it is the only known animal species on Earth to incorporate metallic iron compounds directly into its skeleton and external armor.
Biology and Physical Characteristics
Chrysomallon squamiferum possesses a tri-layered shell whose outermost layer is forged from greigite and pyrite—magnetic iron sulfides. Furthermore, its fleshy foot is uniquely sheathed in hundreds of overlapping mineralized scales (sclerites) composed of iron sulfide over conchiolin. The snail lacks a functional digestive tract, obtaining 100 percent of its nutritional energy from dense colonies of symbiotic gamma-proteobacteria housed within a hypertrophied esophageal gland that oxidize dissolved hydrogen sulfide billowing from hydrothermal fluid.
Behavior and Ecology
These slow-moving armored mollusks cluster in dense colonies at the base of active hydrothermal vents at depths of 2,400 to 2,800 meters, where water temperatures exceed 350°C at chimney mouths but cool to 2–10°C in surrounding waters. Their heavy iron scales provide vital dual protection: defending against predatory vent crabs while neutralizing toxic sulfides through mineral precipitation.
Conservation and Human Impact
Assessed as Endangered on the IUCN Red List—becoming the first deep-sea vent species ever declared endangered—the scaly-foot snail occupies a global range estimated at a mere 0.02 square kilometers across just three known vent fields. The entire species is critically imperiled by prospective deep-sea polymetallic sulfide mining licenses granted for the Indian Ocean seafloor.
Interesting Factoid
The scaly-foot snail is a real-life suit of iron armor: it builds its shell and body scales out of real magnetic iron sulfides, making it the only animal on Earth that literally sticks to magnets!
Last updated: October 2026