Killer Coneshells

Class: Gastropoda

Family: Conidae

Species: Top: Conus geographicus Linne 1758
Bottom: Conus textile Linne 1758

English Name: Top: Geography cone
Bottom: Textile cone

Locality:  Zanzibar for the geographicus, Philippines for the textile.

Images: geograhicus: Sony Mavica digital camera.
textile: courtesy of Paul Kersten

As briefly related in the previous Mollusc of the Moment, the animals which create the beautiful and diverse Cone shells (and i'd like to note here that one must never confuse shells, which are the "skeleton" of the animal, with the animal itself: so often, even in reasonably scientific articles, one will be presented with such inanities as "The Glory of the Seas cone shell lives at moderate depths in the warm waters of the western Pacific....." - just a pet peeve, but i think it important to bear in mind that shells are carefully made by living organisms, and are not like rocks or coins, which have no connection with life.), are hunters by nature, and belong to a group ("superfamily" to be exact) of molluscs which use hollow harpoon-like barbs to spear and inject toxins into their prey, paralyzing them before they have a chance to get a way. The other members of this group include the Terebras (Terebridae) and the seemingly innumerable Turridae. These other families are not harmful to humans, but some cone species most certainly are.

Conotoxins (the poisons which cones use to paralyze their victims) are a fascinatingly diverse group of relatively small proteins which affect the nervous system. The majority are fast-acting toxins which paralyze the nerves of the animal in general, while others are stimulants which cause muscles to cramp violently - both methods being quite effective methods of stopping their prey in their tracks. Normally, a mixture or "cocktail" of toxins will be injected together, when any particular species attacks. There are three basic groups of Cone species, based upon what they feed upon: worms (vermivores), molluscs (mulluscovores) and fish (piscovores). In mollusc-eating cones, several different injections containing different mixtures of venoms are sequentially injected, while in the others, one dart is usually all it takes, although for particularly feisty prey, or for defense against a large animal such as a person, several "harpoons" (technical name is radulae - the "teeth" of the mollusc) may be used in quick succession. Many dozens of conotoxins are known, and several kinds are being investigated as possible drugs, mainly for pain killing or analgesic properties. A particular poison created by the most variable cone in the world, shell-wise, Conus magus L., 1758 (Linneus named most of the really common species, so his name pops up a LOT when living things are mentioned. His goal was to describe all the species in the world, and while he gave it a pretty good shot (anyone know how many species he described in his lifetime?), he could of course only scratch the surface of the estimated 100 million species our endangered biosphere is though to contain (of which only 2 million or so have been "discovered" and named so far...)), belonging to a group ominously called the "Omega toxins", was thought quite promising as a pain killer for a while, but recent tests have turned up some nasty side effects which include things like unconsciousness - NOT a good thing for a drug to induce in its victims!! The best Conotoxin site on the web is Dr. Bruce Livett's Cone Shells and Conotoxins storehouse of knowledge on the topic.

While many cone species can deliver quite a nice "sting", the group amongst the cones which contains members truly dangerous to humans is that of the piscovores, or fish-eating cone-critters. Since fish are faster-moving and often rather larger than the other groups' prey, the toxins used to paralyze them quickly and effectively must be proportionately stronger. They number about 70 species, but only a handful fall into the REALLY nasty category, and only 3 have been known to kill people: the two featured in this article, and Conus marmoreus - and yes this is another "Linnaean" species!! Of the 30 or so known fatalities related to cones over the years, the overwhelming majority have been caused by Conus geographicus L., which is a large species, commonly attaining a size of over 100mm (4 inches), and feeds upon pretty good-sized fishies - note the width of its "aperture" (sometimes referred to as a "mouth"). It produces and is not at all hesitant in injecting an extremely powerful "Conotoxin cocktail" which can kill a careless collector or diver in 2 to 6 hours. Initially, a sharp, strong pain is felt, followed by progressive paralysis, which if it reaches the heart, can kill.

Lest any of the gentle readers (or even the not so gentle ones.... if any!!) develop a fear of going in the water in tropical climes after reading the above "scary stuff", i MUST emphasize that the danger presented by cones, although real, is really pretty small. Cones do not live in places where they could be stepped on easily, and most are completely nocturnal - coming out to feed only at night (some Caribbean species are so light-phobic that they can only easily be found on the darkest of nights when the moon is less than a quarter full!). There is almost no danger of all of accidentally being "stabbed" or stung by a cone snail, so as the song says "don't worry be happy" in this regard. THAT SAID, when collecting cones in Indo-Pacific waters (no dangerous cones are known from the Atlantic Ocean), it is wise to wear thick gloves, and even then to handle the beasts with care, since the larger ones can pierce even wet suit gloves. While only a couple of species can actually kill, being stung by a surprising number of species is no picnic: the pain is reported to be quite fierce and can last up to 12 hours. SO, "caveat collector" would be a smart motto for would-be cone collectors!!

"For the record", if you suspect someone has been stung by a cone, the best first aid treatment is to have them lie down and be calm, restrict the flow of blood from the sting with a pressure bandage (not a tourniquet - you don't want to cause more harm than you are trying to prevent!), and in the worst case, do CPR for as long as it takes to help the patient through. Proper medical care should be sought in ANY case of suspected poisoning on a beach - or anywhere else for that matter!

Conus textile Linne (One can evoke Linnaeus' name in three commonly used ways - as a full-blooded "Linnaeus", simply by the initial "L.", or by the French version of his name: Linne, with a right-leaning accent over the e, which i can't seem to figure out how to do on this keyboard. The later is mainly used by botanists, since the science of botany was extremely active in France in the decades following his pivotal work. Linnaeus was in fact far more interested in "flora" than in "fauna" at any rate, and besides being the "Father of modern taxonomy", is most widely known and regarded as a botanist.) is one of the most variable and most certainly the most common cone species in the world. It can be found throughout the entire tropical and subtropical regions of both the Indian and the Pacific oceans, and lives in "weedy" sandy areas at shallow depths in huge numbers. It displays an astounding variability, with almost two dozen widely-recognized described forms and subspecies.

Conus geographics L., also lives more or less throughout the Indo-Pacific, in a bit deeper water than textile - so it is usually collected by divers willing to take the risk of being stung by them: an unpleasant event even in the great majority of cases, where nobody gets killed except perhaps the mollusc. It is pretty easy to recognize, so i would say to all cone-collectors to be "Don't try this at home", or anywhere else: this is one species best simply left alone. It is easily and cheaply procured from your friendly neighborhood shell dealer at any rate, so the risk associated with this beastie is most DEFINITELY not worth it!!