Parasitic Worm Makes Snail a Zombie So Birds Will Eat It

Anybody who says mama nature doesn’t have a seriously dark side needs to check out this video of a harmless land snail’s eyes pulsating with an assortment of bright colors like a pair of psychedelic lava lamps. Why’s this bizarre yet beautiful display so vile you ask? Because the snail’s not doing it on purpose; it’s the parasitic worm that has infested the snail’s eyes with the intent of having them plucked out by birds. Try to find the grandeur in this one, Planet Earth!

The above video of the snail, which comes via Wired, is a glimpse at what happens when the parasitic flatworm, Leucochloridium paradoxum or “green-banded broodsac,” infiltrates and takes control of a land snail — typically one belonging to the genus Succinea. And if you’re wondering what “takes control” means in this context, it means that the parasitic worm’s broodsacs — literally sacks of brood — take control of the snail’s motor functions and invade its tentacle eyes where they pulsate with different colors in order to make the pair of ocular organs appear to be caterpillars.

Why would the broodsacs want to mimic caterpillars? Because that way they can attract birds that will proceed to eat them. By plucking out the snail’s eyes. ( Gary, be extremely happy that you live in a cartoon pineapple under the sea, because things get mighty freaky on IRL land.


Once a bird has plucked out the zombified snail’s eyes, it inadvertently eats the broodsacs and digests them. Then — yas, this story keeps going — the bird poops out the broodsacs, and the discharged feces keeps the sacs alive and healthy. Once in the feces, the broodsacs are then eaten by another snail. Thus continuing the disgusting, horrific circle of life.

What do you think about this zombified snail and its invading parasitic worm? Do you wish you had never learned about this tragic aspect of nature? Are you just psyched to now have “broodsac” as part of your vocabulary? Let us know in the comments!

Feature image: Gilles San Martin

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