Deadly Beauties

By Alex Scott

cone shell

Textile cone, Richard King.

The animal kingdom is full of contradictions: birds that don’t fly, prey that can’t see, and marine mammals that can’t breathe underwater. But one animal has them all beat: the cone snail may look small and slow-moving, but it is one of the deadliest animals in the ocean, fatal even to humans. But in another contradiction, these venomous snails may also be the key to saving human lives.

The cone snail, known by its taxonomic name as the Conidae family, comprises about 1,000 species, inhabiting tropical waters across the world in rocks and coral reefs. Each species has its own method and material of venom, but all cone snails are predatory animals, capturing fish and worms in a completely unique way. The cone snail has a large tooth called a radula that is stored in its proboscis, a long tube-like structure coming out from the snail’s mouth.

Depending on the species and the type of toxin the snail is using, their methods of hunting prey can vary, but all use their radula as a harpoon that shoots out of the proboscis and deliver the venom to their victim. A cone snail’s venom can contain paralytics, numbing agents, insulin to trigger hypoglycemia, pain reducers to lull the victim, and other “conotoxins” that target specific systems in the body.

hawaiian cone shells

Collection of cone shells, alphabet cone shells, Jennie Altman.

Like monarch butterflies and coral snakes, cone snails are brightly colored to warn potential predators of their secret venomous weapon. For humans, that bright color can mean a beautiful shell to add to a collection, but we are not immune to the cone shell’s deadly harpoon.

pacific cone shells

Textile cone shell, textile and Hebrew cone shells, Jennie Altman.

The smaller cone snail species will only give humans a painful sting, but the larger species like Conus geographus, Conus tulipa, Conus striatus, and other can kill a human with their toxins. Conus geographus is commonly referred to as the “cigarette snail,” because its human victim will only have time to smoke one cigarette before death.

poisonous cone shells

Conus striatus

It is always prudent to check any shells you find to make sure there is not someone still living inside, but in the cone snail’s case it is dangerous to even get close to their shells, so look out for a proboscis sticking out of a shell before approaching it. There is no antivenom available for cone snail stings.

Textile, Striated, Alphabet, Banded Marble, and Tulip Cone shells

Textile, Striated, Alphabet, and Banded Marble cone shells, Jennie Altman. Tulip Cone shell, Kirsti Scott. Tulip cone shells from the Iconographia Zoologica, Th.G. van Lidth de Jeude (1788-1863), R.T. Maitland (1823-1904), Abraham Oltmans (1811-1873), and the Amsterdam society Natura Artis Magistra.

Despite the cone snail’s obvious danger, some scientists are learning from the small gastropods in order to make medicines for human illnesses. A group of biochemists at the National Institute of Standards and Technology is researching the effects of certain conotoxins on the central nervous system of various animals. The chemical properties of these toxins, if they can be reproduced, may prove useful in creating treatments for Parkinson’s disease, nicotine addiction, and various cancers. Researchers at the University of Utah are exploring the pain reducers in conotoxins as a new method of painkiller, particularly as a replacement for more addictive painkillers like opioids. This same group of researchers is also studying using the insulin from conotoxins as a method for treating diabetes in humans.

banded marble cone

Banded Marble cone, Jennie Altman.

All of these studies are only preliminary right now, but they all say the same thing: we humans have a lot to learn from the natural world, even from snails that would harm us to protect themselves. So the next time you come across one of these beautiful but deadly creatures on a coral reef or a rock shelf, be sure to thank it…from a safe distance!

Learn more about seashells

nature and history of seashells and collecting

Learn more about identifying shells, the history of seashell collecting, great shelling beaches, and the lives of the animals who make the shells we find on the beach. Articles ›

No live shelling: Be sure shells are empty and sand dollars, sea stars, and sea urchins are no longer alive before you bring them home.

This article appeared in the Beachcombing Magazine September/October 2021 issue.

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