Cone snails

Cone snails, chiefly the genus Conus and its close allies, are marine snails with a smooth conical shell and a venomous harpoon. The harpoon is a modified tooth from the radula, hollow and often barbed, fired from the proboscis into a worm, a fish, or another mollusc. The venom is a mixture of conotoxins, small peptides that disrupt the prey’s nervous system. Some of those peptides have been studied as drugs. That research happens in laboratories. It has no bearing on how you behave in a rock pool.

A few species can seriously injure or kill a person. Conus geographus, the geography cone, is the species most often named in deaths. Textile cones and others have caused grave stings as well. The shells are beautiful, which is the reason people pick them up. A live cone does not need to be huge to reach the hand that lifts it, and a sting from one of the dangerous species is a medical emergency. There is no field first aid that makes handling them reasonable.

The rule is short. Do not pick up a cone if the animal might be alive. A shell still heavy and glossy, a shell with the aperture covered, a shell tucked under rubble rather than rattling in the wash, is a live animal until it is plainly not. An empty cone is light and worn, and it is often occupied by a hermit crab, which has its own claim to be left in the pool. The pattern that makes the shell desirable can be photographed where it sits.

There are many hundreds of cone species. A large share hunt worms and carry venom that is dangerous to worms more than to people. You cannot sort those from the dangerous species by glancing at a pretty shell with wet hands. Diversity is not an invitation to handle the one in front of you. The harpoon is the point of the animal, and it works faster than a second thought.