Cone Snail

It cheats on speed with chemistry and reach. A fish-hunting cone snail buries itself or waits under cover with only a thin breathing tube and a sensory siphon showing, tasting the water for prey. When a fish is close it extends a long, flexible proboscis, and at the tip is a single hollow harpoon-like tooth. The strike is quick over that short distance, and the venom works in seconds, so the fish is paralysed almost immediately and cannot swim off. Some species, including the geographic cone, first release insulin and other compounds into the water to sedate a whole school, then open a huge distensible mouth and swallow stunned fish whole, sometimes harpooning them once they are already inside.

It varies enormously by species. The many worm-hunting cones give a sting roughly like a bee or wasp. The fish-hunting species, above all the geographic cone, are the serious ones. Their venom can cause intense pain, numbness, swelling, blurred vision, slurred speech, and in the worst cases progressive muscle paralysis that stops breathing. There is no antivenom. People have died, though confirmed fatalities over the last century number in the low dozens. Anyone stung by a large cone should assume the worst, get to hospital immediately, and be ready for rescue breathing, because keeping the airway and breathing supported until the venom wears off is what saves lives.

Do not pick up cone-shaped sea snails, and be wary of pretty cone shells that still have a living animal inside. The snail can reach its proboscis back over almost the entire shell, including the broad end, so there is no safe way to hold one. Most stings happen to shell collectors and to swimmers who pocket a shell or carry one in a wetsuit or bag. If you want the shell, wait until you are certain the animal is long dead, and never handle a live cone with bare hands or let children play with cone shells picked up on a reef.

Because it is an enormous, pre-sorted library of nerve-active molecules. Each cone species makes its own set of conotoxins, and there may be tens of thousands of distinct peptides across the genus, most of them small, stable, and highly selective for one type of ion channel or receptor. That selectivity is exactly what drug developers want. The painkiller ziconotide, sold as Prialt, is a lab-made version of a cone snail peptide and is used for severe pain that does not respond to other drugs. Other conotoxins are in research for chronic pain, epilepsy, and nerve injury, and the venoms are also tools for studying how nerves work.