What's the Difference Between Venomous and Poisonous?

Summer is over, Labor Day weekend has come and gone, and we’re all feeling the sting of being back at work. But is that creeping feeling paralyzing you at your desk the result of poison, or of venom? Let’s find out!  

The term “venomous” applies to organisms that bite or sting to inject their toxins, while the term “poisonous” applies to organisms that unleash their toxins when you eat them

That means that most snakes, contrary to popular belief, are venomous, not poisonous—with the exception of the garter snake, which has a harmless bite but is poisonous to eat because it absorbs the poison of the newts and salamanders it preys on. Other venomous creatures include dangerous spiders, like the black widow; some types of iguanas, like the komodo dragon; and the platypus, which can sting with a fang-like spur on the inner side of each of its ankles. Cnidarians, which include jellyfish, sea anemones, and coral, are also venomous; they sting their prey with the help of nematocysts, small capsules filled with coiled, barbed threads that often contain toxins.  

On the poisonous side of the spectrum, you’ll find most amphibians; many frogs, toads, newts, and salamanders carry around toxins on their skin and in other parts of their body, making them dangerous for humans (and many other animals) to consume.  

When it comes to plants, the line between poisonous and venomous gets a little blurrier. Some plants are straight-up poisonous to eat, such as lily of the valley and oleander. Other plants, though they don’t have fangs, spurs, or nematocysts, are more in the venomous category; stinging nettles, for instance, have bulbous tips that break off when an animal passes by, revealing small, tooth-like structures that pierce the skin and inject a mix of toxins. And poison ivy? Technically, it’s more towards the venomous side of the spectrum; we get those itchy rashes when we brush past it, not when we consume it.

Before you go, here are some poisonous/venomous superlatives, to keep this week’s angst in perspective:

Most Venomous Spider: the Brazilian wandering spider, whose bite can cause muscle shock or even death.
Most Venomous Fish: the tropical stonefish, which is camouflaged to look just like a stone on the ocean floor but has 13 dorsal spines, each equipped with enough toxin to kill a shark (or human).
Most Poisonous Frog: the golden poison frog, which has enough poison to kill ten grown men.
Fastest Venomous Snake: the black mamba, which also happens to be one of the world's most venomous snakes and can move at a speed of 12.5 miles per hour.
Most Terrifying Way to Die: a sting from the Carukia barnesi species of jellyfish, which contains enough of the fight-or-flight hormone noradrenalin to make a human literally panic to death.
