Top 5 Animal Poisons with Amazingly Specific Purposes

Found in the Cone Snail

When you think of animals that can cause horrible death, snails don’t usually make it far up the list. The cone snail, however, is a killer. The complex group of neurotoxins used by the cone snail to kill prey are known collectively as conotoxins, and are some of the most powerful toxins in the world. The reason is that cone snails are aquatic hunters—in the ocean, you have to be able to kill your prey as quickly as possible so it doesn’t swim away first, only to get swept off or eaten by another fish.

Cone snails shoot out a barbed harpoon at their prey to paralyze it, and that’s what commonly leads to stings in curious humans who pick up the shells.

The severity of the sting depends on the species of cone snail. Smaller ones might feel like a bee sting, while larger ones, like the geographic cone snail, can kill you. What’s so unique about these neurotoxins, besides their tremendous strength, is that each one of the 500 or so species of cone snail can have a unique combination of up to 100 different toxins, giving the genus as a whole roughly 50,000 individual toxins to draw from, all of them having evolved in their own special way. For example, there’s one toxin – now a painkiller – that reduces pain so that the victim doesn’t realize it’s about to be killed.

4. Heart Attacks

Found in the Poison Dart Frog

There’s a good chance you’re familiar with the poison dart frog – those brightly colored little frogs that are so poisonous you can die just from touching them – and they are definitely remarkable in a number of ways, but what’s truly incredible is the way these frogs create their batrachotoxin, the main neurotoxin responsible for all that killing.

See, most neurotoxins in the animal kingdom are synthesized from the individual building blocks that make up the molecule of the toxin, all of which happens inside the animal in question. They work like a factory, bringing in raw materials and producing a specific product. In poison dart frogs, the toxin is pulled, already manufactured, from its diet. Its body has evolved so that it has a mechanism responsible for processing and storing batrachotoxin the same way the rest of us process and store proteins, amino acids, and fats. So while most toxic creatures act like factories, the poison dart frog is a raiding party, just picking up the pieces as it goes and doing what it can with them.

We know this is the case because poison dart frogs in captivity are essentially harmless. With a change in diet they completely lose their toxicity, yet when captive frogs, even frogs that were born in captivity, are released in the wild, they will again produce batrachotoxin.

And that’s good news for frog farmers, because a single wild dart frog can contain as much as 1,100ug of the toxin, and, well, it only takes about 130ug to kill an adult human. The toxin works by exciting acetylcholine receptors which eventually causes a heart attack.

3. Feelings of Impending Doom

Found in the Irukandji Jellyfish

The Irukandji jellyfish, or box jellyfish, is one of the most deadly creatures in the ocean, responsible for at least 70 known deaths. It lives off the coast of Australia and is so small (less than 1/4 inch in width) that you rarely ever see them in the wild. Even people who have been stung rarely know what hit them until the paramedic tells them later.

A single sting from this jellyfish (which, again, is smaller than your pinky nail) is so strong that it can bring down a full grown man. Like the cone snail, this is likely due to the law of the ocean: Kill fast so you don’t lose your prey. It’s the same reason the yellow-bellied sea snake is more venomous than any of its land based cousins.

Unfortunately, while a shrimp or small fish will die instantly, humans go through a range of unpleasant symptoms before they die, including (from Wikipedia) “excruciating muscle cramps, severe pain in the back and kidneys, a burning sensation of the hands and face, headaches, nausea, restlessness, sweating, vomiting, an increase in heart rate and blood pressure, and the feeling of impending doom.”

Feelings of impending doom…this toxin doesn’t just want to kill you, it wants you to KNOW you’re going to die a horrible death.

2. Numbness and Tingling

Found in the Hooded Pitohui

If you look closely at that title, you’ll see that it’s pretty much the same neurotoxin found in poison dart frogs. So why are we listing it again? First of all, homobatrachotoxin is a neurotoxin found in the hooded pitohui, which you can probably tell from the picture is a freaking bird. The hooded pitohui is the first discovered poisonous bird, although we’ve found several other species since then.

But it gets crazier. Remember how we said that the poison dart frog gets its toxin from its food? Well, the hooded pitohui lives in Papua New Guinea, roughly 10,000 miles across the Pacific Ocean from Central and South America (stomping grounds of the dart frog), and somehow it has evolved this EXACT same biological mechanism that allows it to absorb and later secrete the (incredibly rare) batrachotoxin family of neurotoxins.

Even assuming they eat the exact same diet (they don’t), the chances of two entirely different classes of animal developing the same bizarre evolutionary trait despite full geographic separation is, well, not impossible, but pretty damn close.

1. Paralysis and Death

Found in the Puffer Fish and Blue Ringed Octopus

The puffer fish is pretty well known, both by its tendency to balloon out hilariously at the first sign of danger, as well as its reputation as one of the more deadly sushi platters. The toxin responsible is known as tetrodotoxin, which is actually taken from the order name that encompasses puffer fish, tetraodontiformes.

But – you guessed it – it gets crazier than that. The same neurotoxin, which is 100 times more deadly than potassium cyanide, is found in blue ringed octopus, a few newt species, and an entire family of sea snails. That’s because tetrodotoxin is actually produced by bacteria which has developed a symbiotic relationship with all of these different marine animals. For whatever reason, these animals have evolved to be able to coexist with this bacteria in a mutually beneficial relationship.

Picture it like this: The bacteria is a gun. Some things use it for defense, others for offense, but the bacteria doesn’t give a crap either way; as long as it continues producing this one byproduct, it will have a home. So while all the other neurotoxins on this list are either defense mechanisms or tools for predation, tetrodotoxin is simply a lucky break for a neutral bacteria, like someone who discovers he can juggle and gets high-paying job with a traveling circus—a circus that just so happens to kill people.