Snail has an iron-plated shell
Pretty cool. Clive Thompson at Collision Detection:
Life isn’t easy for the “scaly-foot gastropod”. This humble snail lives in hydrothermal vent fields two miles deep in the Indian ocean, and is surrounded by vicious predators. For example, there’s the “cone snail”, which stabs at its victims with a harpoon-style tooth as a precursor to injecting them with paralyzing venom. Then there’s the Brachyuran crab, which has been known to squeeze its prey for three days in an attempt to kill it. Yowsa.
Ah, but the scaly-foot gastropod has its own tricks. To fight back, it long ago evolved a particularly cool defense structure: It takes the grains of iron sulfide floating in the water around it and incorporates it into the outer layer of its shell. It it thus an “iron-plated snail”.
Oh yes way. Scientists discovered Crysomallon squamiferum in 1999, but they didn’t know a whole lot about the properties of its shell until this month, when a team led by MIT scientists decided to study it carefully. The team did a pile of spectroscopic and microscopic measurements of the shell, poked at it with a nanoindentor, and built a computer model of its properties to simulate how well it would hold up under various predator attacks.
The upshot, as they write in their paper (PDF here), is that the shell is “unlike any other known natural or synthetic engineered armor.” Part of its ability to resist damage seems to be the way the shell deforms when it’s struck: It produces cracks that dissipate the force of the blow, and nanoparticles that injure whatever is attacking it: …