Hand-colored scanning electron micrograph showing the tip of a Conus snail harpoon tip (Conus ssp), by Martin Oeggerli.
Cone snails are marine species that have shells shaped like geometric cones, often with colorful patterning on the surface. All cone snails are venomous. The most dangerous species are the larger cones, which prey on small bottom-dwelling fish, while smaller species prefer to hunt marine worms. Cone snails haunt using a hypodermic needle-like modified radula tooth to attack and paralyze their prey before engulfing it. The tooth, or harpoon, is primarily made of chitin and barbed, similar to a harpoon. The snail can extend its harpoon(s) some distance out from the proboscis when it detects a prey animal nearby. At the same time the harpoon will be loaded with venom from the venom bulb and, still attached to the radula, it can be fired from the proboscis into the prey by a powerful muscular contraction. The venom paralyzes small fish almost instantly. The snail can then retract the radula, drawing the subdued prey into the mouth.
Cone snail venoms are mainly peptides, containing hundreds of compounds with different and specific (!) effects. The exact composition of the venom varies widely between species. Cone snail venoms have been propelled into the focus of scientific research as a source of new, medically important substances. The appeal for creating pharmaceutical drugs is the precision and speed with which the various components act; many of the compounds target a particular class of receptor, to the exclusion of any other. This means that, in isolation, they can reliably and quickly produce a particular effect on the body’s systems without side effects.