Buckeye Herps Blog

A photographic journal of the reptiles and amphibians of Ohio, Michigan and other places interesting wildlife call home.

Thursday, September 22, 2011

Ohio Snake Identification - Venomous or Not?

I am contacted by many people each year asking for help to identify snakes they find in their yard.  Many are just curious as to what animals call their yard home, or what they saw while camping.  I would be lying if I didn't mention that most just really want to know if they are in danger and often adopt the approach of "shovel first, questions later".  Is it "poisonous" or venomous is more often than not top of the list of questions they ask.  My hope is that this will address some of those questions and help provide a place for others to ask their questions and contact me more easily if needed.

If you don't care if it is venomous, still feel free to leave comments or contact me as directed below.  You may look at the pictures under the Reptiles tab to try and figure out what snake you have seen.

Ohio Venomous Snakes

Ohio has three species of venomous snake.  That is three species out of the twenty five snake species that call Ohio home.  They are the eastern massasauga rattlesnake (Sistrurus catenatus), the northern copperhead (Agkistrodon contortix) and the timber rattlesnake (Crotalus horridus).  Unfortunately, due to habitat loss, road mortality and persecution, both the timber rattlesnake and massasauaga rattlesnake are listed as state endangered species and can only be found in very specific locations in the state.  It is highly unlikely that most Ohioans will ever encounter these animals.

Here are some general rules for identification when you are looking at a snake in front of you.  These rules only apply to Ohio and snakes that can be found in the wild.




1. Vertical pupil vs round pupil - All of Ohio's venomous snakes have vertical, cat-like, pupils.  Ohio's nonvenomous snakes do not.  Again, outside of Ohio, there are snakes that do not follow these rules.  Here are pictures of all three of Ohio's venomous snakes that clearly depict the vertical pupil.

Timber Rattlesnake

Copperhead

Massasauga Rattlesnake
And a nonvenomous snake, the eastern milksnake.  This snake is commonly confused for a copperhead or massasauga rattlesnake.


2.  Presence of a facial pit - All of Ohio's venomous snakes are pitvipers.  They have a heat-seeking pit that helps them localize their prey.  The are ambush predators, and will sit and wait for a small rodent to run by, sometimes at night, and their pits help them hunt.  Ohio's nonvenomous snakes do not have these heat-seeking pits.

Timber Rattlesnake - pit is easily visible to the left and below the eye, just like in the above drawing.
Massasauga Rattlesnake
Copperhead
Northern Watersnake, nonvenomous - note the lack of a vertical pupil or pit.  These are often confused for copperheads.

3. Divided anal plate and double tail ventral scales after the cloaca vs single anal plate and tail ventral scales after the cloaca. In normal terms, the nonvenomous snakes have a split or divided scale that covers their cloaca.  The cloaca is the opening (butt) of the snake where feces (poop) is excreted.  The scales after the anal scale will also be divided or doubled. Venomous snakes of Ohio have a single anal scale and single scales after.  I will obtain pictures of anal scales soon, but please refer to the above figure.

4. Presence of rattle - Two of Ohio's three venomous snakes are rattlesnakes and have a rattle that produces a loud noise.  I will be sure to record one soon as well for you to listen to.  This is not as easy as it seems, as most other nonvenomous snakes will rattle their tails in leaves to mimic the rattling sound.  Also, their copperhead will also rattle it's tail, although it does not have a rattle.  Finally, young rattlesnakes just have one segment of rattle, or a button, and their tails will not make noise.  If you see a rattle, or hear a rattle, it is best to just walk away.

Timber Rattlesnake rattle
Massasauga Rattlesnake, with large rattle, saying "Stay Away"
Massasauga Rattlesnake, neonate or baby, with single button
 5.  Triangular head vs Rounded head - It is true venomous snakes often will have a triangular head.  Many nonvenomous snakes will flatten their neck and change their shape slightly to look more triangular.

Timber Rattlesnake - displaying the triangular head shape
Northern Watersnake with a fairly triangular head
Eastern Hognose Snake showing a triangular head
Remember, most of these snakes have specific habitat preferences and needs.  They are not found all over the state.  Just because a snake lives in Ohio, does not mean it lives in your area as well.  If you draw a line from Cincinnati to Cleveland, a very general rule is that Massasauga Rattlesnakes occur sporadically in the NW half of the state, while Timber Rattlesnakes and Copperheads occur only in the rocky, hilly region in the SE half of the state.

Now, you are probably reading this and saying "BuckeyeHerper, you are crazy if I am ever going to be close enough to a snake to look it in the eye, or lift it's tail to check the butt."  I agree completely, but I do not feel this is a reason to kill the snake. If you aren't sure, just keep a safe distance and leave the snake alone.  Luckily snakes are not as aggressive as people typically think they are.  They will run more often than not.  If they do happen to stand their ground, you can very easily walk away or around them without any worry.  If you are comfortable, everyone has a digital camera or cell phone these days, and it is easy to take a quick picture from a safe distance.  You can then compare your picture with pictures on this and other websites, or email it to me or others for assistance.

Again, if you aren't sure, just keep your distance.  These snakes are very rarely encountered, and chances are you have just found one of the more common nonvenomous snakes.  Despite what you might have heard, Ohio also does not have any cottonmouth, or water moccasins.  The closest populations are hundreds of miles away.

If you have any further questions, or want to share pictures or stories, please feel free to leave a comment below or email me at foltjr AT gmail.com .

9 comments:

  1. This comment has been removed by a blog administrator.

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  2. In paragraph 3 you have the description backwards. Non-venomous snakes have the split scales, venomous snakes have single scales behind the cloaca.

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  3. Thanks, I can't believe I didn't catch that earlier.

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  4. Whatever the case is today, 40 years ago ther were some Timber Rattlers in Morrow county.

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  5. that was helpful thanks! my son was bitten by a snake and i'm happy to be more informed now.

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  6. Thank you very much for the site and all of the pictures to compare. Well done!

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  7. This page is pretty cool I just have one question I've heard more than once that black snakes or water snakes are cross breading (I know better) but am afraid that this might confuse the less intelligent and cause them to kill every snake they see and that pi**s me off

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  8. So is water snakes are poisonous watermark because I have one that I cut

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