Venomous vs. Poisonous: Is There a Difference?

poisonous or venomous? — Is the blue dart frog a venomous animal? Is the rattlesnake a poisonous snake? Or are we using the terms poisonous and venomous incorrectly? Don Farrall/Martin Harvey/Getty Images/HowStuffWorks

You cross paths with a terrifying snake and immediately ask yourself: Is that a poisonous snake? But is that the correct term? Probably not. There are a lot of poisonous animals, but few snakes are among them. Chances are that snake is a venomous animal instead.

And therein lies the premise of this article. You see, the two terms are often used interchangeably and incorrectly. So we are here to give you the ammunition you need to win the argument venomous vs. poisonous. Because they are not the same.

Venomous vs. Poisonous Animals

Venomous animals and poisonous animals are both bad news as they both involve toxic substances that cause physical effects. How they deliver those toxic chemicals is what makes the difference.

Poison is passive: You have to bite or touch the animal for that animal to deliver its toxin. So the aptly named poison dart frog, which secretes a toxin on its skin, has to be touched or licked to harm its enemy. The pufferfish, which is famously poisonous but edible, has to be prepared meticulously in order to be eaten. Poisonous animals and mushrooms are often brightly colored as a warning to predators: Don't eat or touch me!

Venom is active: Venomous creatures have to bite or sting you (or poke you) for the toxin to get into your body. Snakes and spiders, for instance, are venomous, not poisonous.

Not all toxins are the same. Some only make a creature taste bad, like the monarch butterfly. They eat toxic milkweed plants and the toxins in the plants give the butterflies a bitter taste. But other animals are incredibly deadly, and have toxins that can cause extreme pain do serious damage to the nervous system.

The Most Toxic Animals

Asian tiger snakes are one of the few poisonous and venomous animals. They eat poisonous toads and can release the stored-up toad toxin on their prey. feathercollector/Shutterstock

Remember, there are very few poisonous snakes. Most are only venomous. Like the rattlesnake. It's venomous because it fills its fangs with its toxin and directly injects that into its foe.

The platypus, maybe surprisingly, is also venomous. The males have spurs on their ankles that they use on to inject venom into predators.

There are even a few creatures that are both venomous and poisonous. The blue ringed octopus is one. It has a venomous bite, but if that doesn't stop predators from trying to eat it, it's also poisonous once it's in their belly. Yikes.

The Asian tiger snake is another animal that's both venomous and poisonous. One wild defense mechanism it has is from special glands in its neck. It can release the toxins of poisonous toads it eats to ward off prey. But the Asian tiger snake also can also inject venom through small fangs located at the rear of the mouth that is debilitating to the nervous system.

Some people believe mongooses are toxic, but actually they're just better at handling toxins than almost any other animal on the planet. They kill and eat notoriously venomous snakes like cobras.

Armed with your new knowledge, you can probably see the trick now. Cobras are venomous, not poisonous. So the mongoose is ingesting the cobra's toxin, which gets broken down by the acids in the mongoose's stomach. Also, the mongoose can tolerate a little bit of snake venom.

Even plants can be counted as venomous or toxic. Poison ivy is correctly named, as its toxin is delivered by merely touching its leaves. Stinging nettles are venomous, if you're being generous with the term, because they deliver their irritating toxin via spines.