Snails Use Light To Defend Themselves

Animals use a lot of things to defend themselves: skunks use bad odor, armadillos use their tough leathery armor shell, and porcupines use their sharp quills.
But scientists studying the clusterwink snail have discovered what could be the strangest defensive weapon used by an animal: light.

Dimitri Deheyn and Nerida Wilson of Scripps Oceanography (Wilson is now at the Australian Museum in Sydney) studied a species of "clusterwink snail," a small marine snail typically found in tight clusters or groups at rocky shorelines. These snails were known to produce light, but the researchers discovered that rather than emitting a focused beam of light, the animal uses its shell to scatter and spread bright green bioluminescent light in all directions.
The researchers, who describe their findings in the Dec. 15 online version of Proceedings of the Royal Society B (Biological Sciences), say the luminous displays of Hinea brasiliana could be a deterrent to ward off potential predators by using diffused bioluminescent light to create an illusion of a larger animal.

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