How to Tell if a Snake is “Poisonous”

Summer is in full swing, and with summer comes hiking!!! (among other outdoor activities, of course) You know who else loves summer, though? Snakes! Learn how to tell if a snake is poisonous so you can frolic safely.

Blog graphic - how to tell if a snake is poisonous

How NOT to tell if a snake is venomous

You’ve probably seen this chart floating around:

FALSE Venomous vs. Nonvenomous snake chart

This chart is WRONG!

Granted, this is useful for identifying rattlesnakes and other vipers (though I’m not sure about the subcaudal scales). But in terms of identifying venomous snakes in general, it’s bogus.

There are several snakes with round eyes and oval heads that are actually extremely venomous.

  • For example: the black mamba

    how to tell if a snake is venomous - black mambas

    Don’t be fooled by the cuteness.

  • Another example: the king cobra

    how to tell if a snake is venomous - king cobra

    Round pupils? Check. Venom? Also check.

And there are lots of snakes with slit pupils that aren’t venomous at all.

  • Ball python How to tell if a snake is venomous - ball python
  • Green tree pythonHow to tell if a snake is venomous - green tree python
  • Red-tailed boaHow to tell if a snake is venomous - red tail boa

And then there’s the snakes that look evil and like they should be crazy deadly, but NOPE.

How to tell if a snake is venomous - eastern indigo

Eastern Indigo. Fun fact: they EAT venomous snakes!

You get the idea.


How to tell if a snake is poisonous…I mean venomous

1) Is it a viper?

How to tell if a snake if venomous - rattlesnake

Rattlesnake — North America’s most distinguished viper.

All vipers are venomous, so if you can identify one, you’re in good shape.

  • triangular head
  • fat/stocky body
  • rough scales

2) Know the snakes in your area.

I know. Research. Lame. But because snakes are diverse and beautiful, it’s really hard to create a general rule for identifying which ones are venomous. All it takes is a quick Google search to find names and pictures of the snakes to look out for in your part of the world. If you’re in Australia…I’m sorry.

For example, venomous snakes in North America include the coral snake, cottonmouth/water moccasin, copperhead, yellowbelly sea snake, and several species of rattlesnake.

As a final note, please enjoy this cartoon about the difference between venomous and poisonous. Because THERE’S NO SUCH THING AS “POISONOUS” SNAKES. Learn the difference and impress your friends!

Venomous vs. poisonous snakes


  1. There are some in the genus Rhabdophis that are actually poisonous and venomous. Pretty facsinating actually.