Cone snail

Cone snails are part of the phylum Mollusca and the class Gastropoda. These snails can grow to lengths of 23 cm and their beautifully ornamental shells are considered collectors items by many people. They occupy tropical marine waters and are found mostly in coral reefs.

Cone Snails are carnivorous, mainly feeding on small fish, marine worms, or even other mollusks. There are an estimated 500 species of Cone Snails. They are divides into three groups according to their diet: piscivores - fish eaters, molluscivores - mollusk/snail eaters, and vermivores - worm eaters.

Cone Snails use a venomous harpoon (called a toxoglossan radula) to catch quick-moving prey. They are the world's most venomous mollusk, and were equipped with these harpoons because they are extremely slow and cannot catch prey otherwise. Amazingly, in some of the species, the venom is powerful enough to kill a human being. There have been 30 recorded cases of human deaths as a cause of Cone Snail stings. .

Anatomy
All Cone Snails are larger and wider at one end and narrow at their base. They all have spires, (whorls above the body whorl) or different heights at the larger and wider end. A whorl is the full turn of a shell. Shells can be dull, or very shiny. They can be smooth, or very lined and bumpy. The shell has an aperture (opening). It is long and narrow. The foot of a Cone Snail is strong and muscular and can be colorful. The siphon is well developed and can also be colorful. A Cone Snail's harpoon is hollow and barbed and is connected to the radula in the top of the snail's throat. Its harpoon is a modification of the radula, an organ found in Mollusks that acts as both a tongue, and as teeth. When a snail senses prey, it turns its mouth, which is a long and flexible tube, towards the prey. The snail then fires the harpoon into the prey by a powerful muscular contraction. Their average attack lasts only milliseconds. The venom paralyzes the prey and it is killed nearly instantly. Venom in Cone Snails contains hundreds of different compounds. Venom varies from each species to the next. Conotoxins is the name for the toxins found in these different venoms. The venom will also contain a pain reducer, it starts by pacifying the prey, immobilizing it, and then killing it. Some Cone Snails carry the same toxin as that in puffer-fish, blue-ringed octopus, and rough-skinned newt. Cone Snails are one of the most toxic creatures on earth.

Reproduction
Reproduction in Cone Snails has not been widely studied, but it does appear that most of the snails have separate sexes and that they fertilize internally. Eggs are laid and attached to substrate. The eggs are laid in capsules, and each capsule will contain a varying number of eggs. Two types of offspring or hatchlings have been noted. The veligers (free-swimming larvae), and veliconcha (much like baby snails).

Ecology
Cone Snails are marine snails, and are found mostly in coral reefs. They are generally found in shallow waters either near coral reefs, under coral shelves, hiding in the sand, or under piles of rocks or rubble. There are some Cone Snails that live among mangroves, which are trees and shrubs that grow in saline coastal habitats. They have been located in places including the Indian and Pacific Oceans, the Great Barrier Reef, Australia, Hawaii, and California.

Medical Uses
In some Cone Snails, the venom has shown good promise for providing a non-addictive pain reliever 1000 times as powerful as morphine. The first pain killer, Ziconotide, was derived from Cone Snails and was approved for use by the Food and Drug Administration in December 2004. Other drugs are now in trial. Some of these could eventually be used in the treatment of Alzheimer's disease, Parkinson's disease, and epilepsy. Cone Snail venoms contain substances called conotoxins. Conotoxins are very small, measuring about 20-30 amino acids in length. Their short length makes them fairly easy to manufacture. If you are stung by a Cone Snail, it is important to seek medical attention immediately. If you come upon a Cone Snail, it would be wise not to handle it. Symptoms of a Cone Snail sting include intense pain, swelling, numbness, and tingling.