Just When You Thought It Was Safe to Go Back in the Water: Blood-sucking Snails
It’s okay, unless you’re a fish
I was bitten by a snail once. It wasn’t a surprise attack. I had seen a pond snail (Lymnaea stagnalis) eating a dead tadpole and wondered if I could persuade it to do the same to my finger tip.
The snail took to the job enthusiastically, attacking my skin with hundreds of tiny teeth. Within seconds, those teeth had scraped away the outer layer and exposed the painful one beneath. Before it drew too much blood, I put the animal back in the aquarium. Then I went in search of iodine and a dressing.
I did not repeat the experiment.
Many snails are carnivores. Some cone shells (Conidae) are active predators of marine fish, first paralysing prey with venom and then swallowing it whole. Violet snails (Janthina) float on bubble rafts, pushed around by sea breezes that bring them into contact with their food — Portuguese Man-o-War (Physalia), By-the-Wind-Sailors (Velella), and other species that live at the interface between ocean and air.
Land snails are sometimes fearsome predators. No, really. Members of family Rhytididae are almost exclusively carnivorous, as are those of Spiraxidae. American readers might be familiar with the Rosy Wolfsnail (Euglandina rosea…
