The Cone shell is an unassuming looking creature and begging to be picked up and looked at……
If you do pick up a Cone shell or Cone snail, you could be taking your life into your hands!
The shell (Conidae) have about 500 species in the family, all evil little things waiting to leap out and spike you! Of course that isn’t true but once you know about them it is amazing how many you see on the reefs, until I realized how dangerous they were, I used to pick up their shells for a look all the time…..
What’s it all about?
The Cone shell has varied levels of toxicity with varying levels of effect on humans. The small Cone shells may be no worse than the sting of a bee, while the larger tropical Cone shells have occasionally resulted in deaths.
The problem, for Humans, comes from a sort of tongue which has teeth on it (radular) as well as a modified hollow tooth that the Cone shell thrusts out of its mouth carrying with it a poison containing neurotoxins. The effect is similar to that of a barbed spear stabbing the victim.
This is designed to very quickly disable its prey, hence the strength of the poison. You can imagine the chances of a snail catching up with its prey if it had a chance of moving anything more than a couple of inches away once ‘speared’?
The tongue draws the victim back into its mouth where it digests all but the hard parts of the victim which it then regurgitates along with the used ‘harpoon’.
Each snail has several of these harpoon like teeth and is capable of shooting them any many directions, even backwards.
The larger Cone shells tooth is capable of penetrating gloves or wetsuits.
The effects of being stung by the more potent Cone Shells is similar to that of being bitten by a venomous snake.
At first the sting causes a shooting localised pain, followed by the numbness of the affected limb. The venom gradually blocks the extremities nerve action causing a tingling sensation, swelling and rash follow, then giddiness, vomiting and later sharp pain.
Fairly quickly the diaphragm also is affected and respiratory difficulties begin when the lungs begin to be paralysed.
Dizziness and difficulty in focusing with problems in the throat and in particular swallowing.
The death is usually as a result of respiratory failure followed by heart attack.
Only about 15 deaths can be confidently attributed to Cone snail stings.
The advice to be given is - don’t just handle them carefully, don’t handle them at all!
They look typically as you would expect from the name – like an ice cream cone with the wide end obviously being the business end of the Cone shell.
The larger members of the species grow up a length of 23 cm or nearly 8 inches – these would pack one hell of a ‘punch’.
They tend to be brightly colored and with attractive patterns (generally why people like me want to pick them up…).
They are found in most tropical waters as well as there being some species which have adapted themselves to more temperate waters like the Cape Coast of South Africa and the cooler waters of California.
They live in or around coral reefs with sub-tropical species found amongst the rocks in the areas close to the shore areas.
Cone shell venom shows great promise as a source of new, medically important substances. The venom contains a pain reducing toxin to pacify the victim. This is being studied for its medical potential.
The pain killer this may produce is 1000 times more powerful than morphine and non-addictive, it shows potential for being the replacement for morphine.
The first drugs commercially produced and approved by the Us Food and Drugs administration, Ziconotide sold as Prialt, were approved in 2004.
Other drugs are in clinical and preclinical trials, such as compounds of the toxin that may be used in the treatment of Alzheimer's disease, Parkinson's disease, Epilepsy, arthritis and even cancer.
What do they eat?
They prey on worms, small fish, other mollusks as well as other Cone shells. As I mentioned earlier the venom of the larger Cone shells is strong enough to kill a human.
There is no antivenom and in more serious cases the treatment is life support until the venom has passed out of the body.
The affected part should be immobilized and apply a pressure bandage to slow down the dispersion of the venom.
Keep the Cone shell (somewhere it isn’t going sting again?).
Administer a pain killer for the pain.
Even if the pain is not great and the sting seems harmless, seek medical advice.
At the end of all this there is no need to be paranoid about Cone shells, of the over 500 species about 20 are potentially dangerous to humans and quite difficult to come into contact with.
Again, usually only the larger Cone shells are toxic enough to cause a fatality.
To read about more dangerous creatures like the Cone shell, click here.