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The venomous animals on your plate

Venomous creatures are everywhere - including in your dinner.

More than 200,000 venomous animal species are known to science, including bees, snakes, spiders, jellyfish, mosquitoes and snails.

It was recently discovered that octopuses, cuttlefish and squid are venomous, capable of delivering a toxic bite.

It means that when you eat a plate of fried squid, you're getting up close and personal with the ocean's venomous creatures - although of course, their venom can do you no harm once the animal has been killed, cooked and served.

Dr Ronald Jenner, a venom evolution expert at the Museum, and his colleague Dr Eivind Undheim from the University of Queensland, have released a book on the power, diversity and evolution of venom.

A squid underwater

All squid are venomous, although none pose a danger to humans © Frovola Elena/


They write, 'The next time you are enjoying a dish of Southern calamari in a restaurant you may want to reflect on the fact that you are eating a venomous predator.

'Sepioteuthis australis is just one of about 290 species of squid, which together with their cuttlefish and octopus cousins,  contribute to the millions of tonnes of cephalopods caught annually worldwide.

'The venom of the Southern calamari is a toxic cocktail, one component of which is a neurotoxin that causes paralysis anddeath in crabs, a favourite  cephalopod prey. Gram for gram this squid venom toxin is as deadly to crabs as the most lethal snake venom toxins are to mice.'

A blue-ringed octopus

Blue-ringed octopuses live in warm, shallow coastal waters and are some of the deadliest animals in the sea © Sascha Jansen/


A recent discovery

A breakthrough study published in 2009 found that far more cephalopods were venomous than previously thought.

With the exception of the handful of living Nautilus species, all cephalopods are thought to be venomous.

Only the tiny blue-ringed octopus is dangerous to humans, but the rest also use venom to catch prey. They deliver the toxic cocktail via their mouthparts, using their sharp beaks to create holes in crab shells and spitting venom inside.

This method of killing prey went unnoticed by science for a long time, possibly because the effects of this particular venom on humans are mostly mild.

The scientists, from the Free University of Brussels, the University of Melbourne and Museums Victoria, found that venomous squid and octopus all share one common ancestor, which passed on a capability to create venomous proteins. 

A scorpion

Scientific research about venom is most often undertaken on snakes, spiders, scorpions and cone snails because these species pose a threat to humans © Chaikom/


Cephalopods are classed as venomous rather than poisonous because they deliver their toxins via a bite or wound. Poison is passively absorbed into the blood through skin, or eaten.

This discovery could have implications for future medical breakthroughs, as the venoms of other creatures have been successfully used to create remedies for a host of diseases, including diabetes.

Ronald says, 'Venomous animals play important ecological roles in their local habitats, and they provide many benefits that are woven into our own lives.

'Venom can often be an incredible force for good.'

The evolution of venom

Ronald is also researching how venom evolved in animals including centipedes, toadfish and marine crustaceans.

Current scientific understanding of venom is disproportionally based on research about snakes, spiders, scorpions and cone snails because these species can kill humans. But there is much more to learn about the production of these toxins across the animal kingdom.

Venoms have evolved in the animal kingdom about seven dozen times independently, in animals as varied as jellyfish and the platypus.

He says, 'Sea anemones, jellyfish and their cnidarian kin have used venom for well over half a billion years to procure their food, defend themselves and compete with neighbours.

'But venom is such a useful adaptation that thousands of other species have also separately evolved the ability to use it.

'We are investigating the many ways in which that has happened.'