Cone snails might move slowly but the venom from one of these animals could kill 700 people – but might also help diabetes treatments, says Melissa Hobson.
What are cone snails?
They are cone-shaped predatory marine molluscs that use a potent toxin to incapacitate their prey before killing it. Depending on the species, they eat worms, fish or other molluscs. Although these venomous snails don’t target humans, they have been known to harm or even kill people who unwittingly pick up or step on one, triggering a self-defence response. The fish-eating types are the most dangerous to humans.
They are one of the deadliest animals in the ocean
What are the different types of cone snail?
Perhaps the most famous of the hundreds of different species of cone snail is the geography cone snail. This animal is also known as the cigarette snail because of the limited time you’re said to have after being stung by one before death takes hold – just long enough to smoke one last cigarette (although this is rather an exaggeration).
How do cone snails get their name?
These animals get their name from their conical shape.
How big are coin snails?
Different species come in a variety of sizes – from just over a centimetre to nearly 22cm – and patterns. They are often brightly coloured with delicate patterns, making them popular with shell collectors.
How do cone snails hunt their prey?
These carnivorous predators have a clever strategy for hunting prey. They might move slowly but they don’t let that stop them catching something to eat. To subdue a passing fish, some species squirt chemicals into the water as their prey swims by.
This chemical cocktail, which includes insulin, reduces the animal’s blood sugar levels and puts the victim into a stupor as if they’re in a coma. This leaves the prey helpless and unable to defend itself – so the snail can kill and eat it without a fight.
What is the venom they deliver?
Cone snails also deliver a strong neurotoxin that paralyses their victim. They do this using a harpoon-like structure in their radula that shoots the toxin into the victim, immobilising them at once. They can then eat them whole. Their strike is one of the fastest in the animal kingdom.
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Where do cone snails live?
They typically live in warm or temperate shallow waters, although some species can be found deeper. These ambush predators by hiding in the sand while waiting for unsuspecting prey to pass by. Staying buried also keeps them out of sight of potential predators.
60 per cent of all known species are found in the Indo-West Pacific.
How do cone snails reproduce?
Not much research has been done into cone snail reproduction but scientists believe many species reproduce sexually before the female lays eggs, which eventually hatch into larvae. Many species only breed once a year.
Can cone snails kills humans?
Yes cone snails can kill humans. Although they are slow moving, cone snails can deliver a highly potent neurotoxin when they feel threatened. Although cone snails don’t target people, their toxin has been known to kill humans who stepped on them by accident or picked them up thinking they were just a pretty shell.
Their toxin is so potent that scientists believe the venom from just one snail could – hypothetically – kill up to 700 people. Geography cone snails are a particularly dangerous species and are believed to be responsible from most known cone snail fatalities.
It's not common for humans to get stung but those who do might experience pain, sweating, paralysis, necrosis of the sting site, coma and respiratory failure. Stings aren’t always fatal but, if left untreated, victims can die in under five hours.
What's the best thing to do if you're stung by a cone snail?
When you’re on the beach, tide pooling, snorkelling or diving, never touch any shells that may still have a snail still living inside – this could harm the animal and might put you at risk too if the snail is toxic. If you think you’ve been stung by a cone snail – or another venomous creature – seek medical treatment immediately.
How can cone snails help diabetic research?
Scientists studying cone snails have found that their venom might be helpful in a medical setting. The insulin cloud that they use to stupefy their victim is incredibly quick – it takes just a few seconds before the fish falls into a coma-like state. If researchers can figure out how the insulin works so quickly, and apply it to diabetic treatments, it could help patients. Currently, it takes around 15 minutes for insulin to kick in for a human.
Although cone snail neurotoxins can be fatal to humans, they can also be used in the development of pain medications that are much less addictive than opioids. Scientists are also investigating how they could help to treat conditions such as epilepsy and multiple sclerosis. Cone snail venom may still have other applications that researchers haven’t yet discovered.
Are cone snails endangered?
Of the hundreds of species of cone snails, many are categorised as a species of Least Concern by the IUCN Red List. Three (Conus salreiensis, Conus mordeirae, and Conus lugubris) are Critically Endangered. Eleven species are Endangered, 27 considered Vulnerable to Extinction, 26 are Near Threatened, and 88 don’t have enough data to be categorised.
Some scientists are concerned that human activities, including pollution, overfishing and urban development, are destroying the homes of these snails and putting them under concerning levels of pressure. Ocean acidification is also a worry for cone snails, as well as other molluscs, because more acidic water can dissolve their shells and prevent them from forming new ones.
