Ocean Facts: Beautiful but deadly cone snails

As if drowning weren't enough, there are so many ways the ocean will end your life. Add to the lethal list of box jelly fish, blue ringed octopus, fugu and the always popular great white shark, the beautiful but deadly cone snails.

Cone snails are predatory animals, stinging their victims with a venomous harpoon-like tooth. Though cone snails primarily use their tooth to subdue prey, it can also be used defensively, stinging other animals, or humans, that get too close. Though all cone snails have venom glands, only a few species are dangerous enough to be fatal to humans.

Cone snails are found in oceans around the world from from shallow to moderate depths and are generally buried in the sand or rubble during the day and are active during the night. They hunt by smell using a siphon which can be extended away from the shell's opening.

Depending on the species, cones may prefer marine worms, snails (including other cones) or sleeping fish. The venomous tooth is located at the tip of the proboscis, a muscular extension of the mouth. Cone snails, one of the largest families of marine snails, have heavy, smooth shells and are much prized by collectors.

When the cone snails shoot fish with their tooth, they hold on to the tooth to keep the fish from swimming away. Eventually the venom, which affects the nervous system and also deteriorates the animal's tissues, takes effect, allowing the snail to eat the fish whole.

By extending the proboscis, the snail can eat its prey without the snail having to leave its protective shell.

The geographic cone is the most venomous of the 500 known cone snail species, and several human deaths have been attributed to them. Their venom, a complex concoction of hundreds of different toxins. There is no antivenin for a cone snail sting, and treatment is limited to merely keeping victims alive until the toxins wear off.

The venom of the geographic cone snail has to be strong enough to paralyze instantly. Otherwise, the fish it preys on would swim away to die, and the slow-moving gastropod would have nothing for its efforts. It's also known, in a gallows humor sort of way, as the cigarette snail, meaing if one stings you, you have just enough time to smoke a cigarette before you die.

Indigenous to the reefs of the Indo-Pacific, geographic cones grow to about 6 inches (15 centimeters) in length and have intricately patterned brown-and-white shells are among the most sought after by collectors.

Ironically, among the compounds found in cone snail venom are proteins which, when isolated, have enormous potential as pain-killing drugs. Research shows that certain of these proteins target specific human pain receptors and can be up to 10,000 times more potent than morphine without morphine's addictive properties and side-effects.

These conotoxins have long interested medical researchers because of their potential painkilling abilities. The venom however, is very complex; each kind contains perhaps 50 or more different chemicals that target the brain and nervous system. Overall, researchers believe that more than 50,000 conotoxins may exist. That diversity has made it hard for them to isolate a specific chemical to work on.

But over the last few decades, conotoxins have begun to give up their secrets. Researchers have published more than 2,500 papers on the chemicals, and have described and identified more than 100 specific toxins which show promise for treating everything from arthritis to cancer.

As with anything of value, both the shells and the pharmaceutical promise of cone snails, has made them a target and they are in danger of being over harvested. At the present time, no cone snail species are listed as endangered or threatened.