Carnivorous Marine Snails, Tina Holt

A wonderful, insightful blog about the unassuming yet mysterious sea snails written by one of our Sea Urchins readers in the US. Thanks, Samantha

‘With its keen sense of smell, brute strength and sharp ribbon of teeth, this predator strikes fear in the hearts of many creatures.  It is a patient hunter, sometimes waiting hours for its meal.   Ferocious and deadly, slimy and slow.  It sounds like a monster from a horror movie, right?  But this creature lives quietly in our oceans. Meet the brutal, carnivorous predator… the sea snail.

Most marine snails are herbivores, using their radula, or ribbon of teeth, to strip algae off of rocks and sea grass.  The radula works like a chain saw, with rows of moving teeth rasping and grating its food.  Some species of marine snails are omnivores, and eat ocean detritus as well as algae.  Still other species of marine snails are carnivores.  They prey on shellfish, worms, and even small fish!

Each subspecies of carnivorous sea snail has a different favorite food, and has adapted its hunting techniques to get its preferred meal.  The horse conch likes to eat oysters.  Once it locates a potential meal, the horse conch wrenches open the victim’s shell with its muscular foot.  The opening doesn’t have to be very large for the snail to insert a tube-shaped organ called a proboscis.  The radula extends out of the proboscis and rasps at the oyster’s flesh.  The predatory snail then sucks the grated oyster through its proboscis like a straw, and digests it in its stomach.

The whelk, a connoisseur of all types of seafood, enjoys oysters as well as other snails and shellfish.  This snail attaches itself to its victim and releases a chemical to soften its victim’s shell.  Using its radula to chip away at the softened shell, the whelk drills a hole big enough for its proboscis to enter.  This drilling can take anywhere from 20 minutes to 10 hours!  Then, as with the horse conch, the shellfish is rasped, slurped and digested.

The deadliest marine snail is the cone snail.  Found in the South Pacific, this snail feasts on worms and small fish.  Unlike the chainsaw teeth of the horse conch and whelk, the cone snails’ radula are sharp, hooked teeth that shoot out of its proboscis like a harpoon or a dart.  Once the cone snail has struck its victim, it releases a paralyzing venom.  The radula, still hooked on to the paralyzed fish, retracts into the cone snail’s body, pulling the entire meal into its stomach.  Inedible bits of fish, such as scales and bones, are ejected after digestion.

With the exception of cone snails, carnivorous sea snails are not dangerous to humans.  Cone snail venom is highly poisonous.  A sting from some species causes a burning reaction much like a bee sting, but the venom from other species can be fatal.  Because of its unique sedative qualities, scientists are studying cone snail venom to develop a non-addictive painkiller for use in hospitals.

So, the next time you see a sea snail at the beach, remember it’s not just a slimy creature with a pretty shell – it has a wild life of its own!


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One comment on “Carnivorous Marine Snails, Tina Holt

  1. Tina Holt on said:

    The wonderful pictures (flamingo tongue, reticulated cowrie helmet and tulip snail) are courtesy of Jack Seubert!

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