Venomous vs. Poisonous, or, How to Exasperate a Reptile Keeper

I made it a few steps out from the back of the Reptile House before the crowd gathered.  It took that long for the first parent to notice the Chilean rose-haired tarantula crouched in the palm of my hand, and with one "Hey, look what he has!", I had half the zoo assembled around me.  Visitors edged closer, some excited, others wary, asking questions and coming in close for pictures.   One little girl approached and I knelt down, holding the hairy spider low for her to see.

"Is he poisonous?" she asked, face screwed up with concern.

"Not even a little," I said cheerfully.  Those assured, she started to smile.  "She is, however, venomous..." Her smile died suddenly.  "But only a little!" I said.  

The crowd instantly gave me a little more space.

There are few ways to annoy a zookeeper more than using the wrong name for an animal (well, I mean, you could throw rocks... or hop fences... or, well, actually, there's lots of things that annoy us more.  Disregard).  The "Venom" vs "Poison" debacle is included with that.  This one is especially irritating to many zookeepers because it seems that the improper usage is plastered everywhere in pop culture.  Even scholarly works and serious journalists sometimes use the wrong terms.  Heck, I've seen zoos and aquariums use the wrong terms.  It drives keepers nuts.

That being said, it never really bothered me much.  I was willing to take advantage of a teachable moment with the tarantula, but hearing visitors call a snake or spider "poisonous" never really got me too worked up.  After all, where are they supposed to learn the difference?  I don't remember it ever being taught in school.

Anyway, this month I'm going to be talking a lot about venomous (and poisonous!) animals, so I figured it would be best to just have the difference spelled out here.

Web comic by Rosemary Mosco explains the difference between venom and poison

Venomous Animals are ones that inject a toxin into their victim (be it predator or prey), using fangs, stingers, or other weapons.  Examples of venomous animals include spiders, scorpions, king cobras, wasps, and, just because, the duck-billed platypus.

Poisonous Animals administer toxins through touch or absorption or ingestion.  Many amphibians, such as poison dart frogs and cane toads, are poisonous, as are some butterflies, blowfish, and a surprising number of birds (and by surprising, I mean the fact that there are any).

In simple words - venomous means it bites you, you die; poisonous means you bite it, you die.  

It's a pretty accurate summation.  Some animals, like the snake eluded to in the first cartoon, are both.  They have a venomous bite, but their flesh may also be poisonous if ingested.  Also, just to be clear, being poisoned or envenomated won't necessarily kill you, but it will have some sort of effect on your body.  Get it?  Got it?  Good...

With that out of the way, we can move on in.