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ID-ing Snakes In The Garden - Cottonmouth

19 years ago

Continuing with the Snake ID series. Below is my original post on how to tell a cottonmouth or water moccasin from any ol' brownish looking water snake you might run across. There are several harmless water snakes that often get misidentified.) The post below is long, but if you read it and look closely at the pictures, I'll bet you will be able to tell if you are dealing with a venomous cottonmouth or not. Hope it helps some of you!

Marcia

***************************************************

The Cottonmouth, Agkistrodon piscivorus, has 3 subspecies, but we are going to concentrate on the FLORIDA cottonmouth, Agkistrodon piscivorus conanti. (Oh, boy...we get our OWN state subspecies! YAY...I think?) All comments, descriptions, etc, that follow will apply specifically to OUR cottonmouth, though the other subspecies are somewhat similar.

Let's start with some general info. Cottonmouths are large, heavy-bodied water snakes that primarily eat fish. (Hence the "piscivorus" portion of their Latin name.) Naturally, if fish make up most of your diet, you need to live near water, and cottonmouths do. Their favorite habitats include swamps, lakes, rivers, irrigation ditches, canals and most any sluggish body of water, though they CAN be found in clearer, faster moving streams once in awhile. But generally, the dark, slow moving streams and lakes in Florida are their favorite places.

If you live on waterfront property, or back up to a canal, you may very easily find yourself confronting a basking cottonmouth one day when you go to mow your lawn, or fish from your dock. If you don't live near water, it is still a good idea to recognize these snakes, since you are bound to be AROUND a lake or stream at some point or other.

Cottonmouths, like most pit vipers, are live bearers and the females give birth to 1 to 15 babies at a time. The young range in size from 7" to 13" at birth, and they arrive fully loaded with venom and ready to bite. Their venom is haemotoxic, and is very complex. It works on the blood tissues, and causes exceptionally nasty wounds. It is designed for killing prey and starting the digestive processes on the animal even before the snake has swallowed it. Snakes are very vulnerable right after they eat. They can't move very fast with a whole rat or rabbit inside them, so before their stomach acid even begins to digest the animal, the poison has started to break it down from inside, speeding up the entire process. And that's just what it does to the tissue surrounding a bite wound...it begins to eat away at it and cause ulceration. You do NOT want to get bitten by a pit viper. So I hope these photos and comments will help you make a positive ID and keep you safe!

The coloring of the baby moccasins is very different from the adults. They are born with a strikingly colorful pattern of bands and markings that gradually darken and fade as the snake ages. Adults are often nearly completely black. But because the snake goes through so many colorations as it ages, it is difficult to identify them by color or markings alone. (No little rhymes to recite and poor Jack isn't even mentioned at all!) So, we have to go by a couple of other field marks, in addition to head & body shape, and behavior. And in Florida, we have one sure-fire identifier that really clenches it.

Let's start with some photos of young snakes and work our way up through some color variations, and I will show you the marking that remains consistent throughout.

Here is a young cottonmouth, coiled up, ready for action. Notice his beautiful splotchy markings, intended no doubt to provide camoflage for him as he is lying in leaf litter or other debris.




Here is another very young moccasin. In this odd pose, you can just barely see that he has a yellow tail tip. This is only found on very young cottonmouths, and it is believed they twitch this tail tip in the water as a lure for small fish or other critters. Heavy bodies, even at this stage, and wedge shaped heads that are wider than the necks are good clues that we are looking at vipers here. But...here's my secret weapon for the ID of cottonmouths... each of these has a very dark brown or black stripe that runs the length of the cheek through the eye to the back of the head. (Hereinafter we will cleverly refer to this as the "cheek stripe.") This wide, dark stripe, usually set off by cream colored areas above and below it, is visible in ALL colorations of the FLORIDA moccasin. It doesn't always show up in the other subspecies, I'm afraid, but for US, it is diagnostic.

In this second image, you can also see two dark marks on the front of the moccasins nose that run downward towards its mouth. These are also very good field marks...trouble is, you almost half to be eyeball to eyeball with the snake to see them, so I'm gonna focus on that cheek stripe, as it stands out nicely, even from several feet away.



The next photo is of a larger moccasin...still showing a lot of color, but not as much pattern as the younger snakes. I'm not totally sure this is a FLORIDA moccasin, as I can't see the side of the head very clearly, but this is typical of many youngish snakes, and I wanted to show you this image for 2 other reasons. First of all, the snake is gaping, exposing the very pale lining of his mouth in the behavior which gives him the name "cottonmouth." I have never seen another snake do this consistently, though that may be my limited experience. But cottonmouths DO. If there is one lying in your path, the chances are very good he will begin this display as soon as he senses your approach. It is his way of alerting you to his presence and announcing that HE doesn't intend to move, so YOU better, if you know what's good for you. (Unlike most snakes, cottonmouths do not tend to hurry away at your approach. That's why I think of them as being SO dangerous. They just lie there like great scaly lumps and gape at you, hoping you will see them and not step on them.)

The second interesting thing about this photo is how clearly it demonstrates that snakes DO have tails. They are NOT "all tail" like some people have asked me in the past. On slender snakes, it is often hard to tell from the TOP where the snake's tail begins, but cottonmouths are so thick through the body and then taper so quickly at the tail that you can really see it. A general heavy shape and short tail are good indicators that you need to take a closer look to be sure what you are dealing with.




Another young snake, much darker in color, resting on a palmetto frond, and gaping away in his "DANGER, I'M A BAD BOY TO MESS WITH mode." You can't see his cheek stripes from this position, but I guarantee you they are there, and you CAN see his "COTTON" mouth, another SURE sign.



This is an older snake, beginning to darken up quite a bit, with some pattern still visible, but obviously on his way to becoming the near black of the big boys. BUT...take a look at that head. See it? YEP, that CHEEK STRIPE is clearly visible, and totally diagnostic.



Another large moccasin, with cheek stripes you can just see from this angle, but he IS gaping nicely, and announcing quite loudly, "I'M A COTTONMOUTH. Don't TREAD on ME." Look how dark his coloring is and how faint the pattern has become. See why you can't go by color alone?




A nice, FAT one crawling away, so it is hard to see his head, but alerted by his general size and width, one should be looking closely enough to see that yes, the CHEEK STRIPES are there, though it isn't a good angle to spot them. However, this is NOT a bad angle to be viewing a cottonmouth from, as he is LEAVING. And that's probably a GOOD thing.



Now for some shots of them in the water. Here is a wonderful view of a really dark adult, swimming ON TOP OF THE WATER. This is an example of a diagnostic BEHAVIOR. Other water snakes swim underwater or with just their heads above water. The cottonmouth swims with his entire body gliding on the surface of the water. This image also shows what we mean by the wedge shaped head which is wider than the neck. Other water snakes do not have heads shaped like this,though I wouldn't try to go by that in identifying a snake, as it is often hard to tell at a glance.



A wonderful photo of a younger, still patterned moccasin that should leave no doubt in your mind as to what it is...first of all, you can clearly see THE CHEEK STRIPE. And secondly, it is swimming with its entire body on the surface of the water. Both of those are dead giveaways.




Another head shot of a still-patterned snake, just to give you another look at that diagnostic CHEEK STRIPE.




These two pictures show some interesting behavior...this large moccasin found a puddle filled with mad toms (wee little catfish) and was FEASTING on them. He totally ignored the photographer and gorged himself. In the first shot, you can see his head sticking out of the water. It was so shallow that he was really crawling rather than swimming. (NOTE CHEEK STRIPE, PLEASE). In the second shot, he is busily swallowing one of the little fish. You can see he is almost black, but that cheek stripe shows just as well as it did when he was young and fully patterned.







And finally, just to show you what happens if you need to have a moccasin removed from your property. I like this shot because it gives you a good idea of how big and truly HEAVY these snakes are. And you can see the short tail clearly...AND...guess what else? Aw, come on...say it! You KNOW you wanna! YES!! You can still see that CHEEK STRIPE.



Okay, that wraps up the basic ID on the cottonmouth. I know it was long, but you really need to see a lot of examples on this guy. His coloring is just too variable to expect each snake to look the same way, but I hope you have learned that there are some things that are always diagnostic. Now you can relax when that harmless brown water snake crawls up on your dock!

Marcia

Comments (37)

  • 19 years ago
    last modified: 11 years ago

    I like snakes but this one makes my heart do flips. Can't help but think of Lonesome Dove everytime I see one.

    Thanks for educating us anyway! Love your lessons on the wildlife!

    Betsy

  • 19 years ago
    last modified: 11 years ago

    Cheek stripe! I never knew about the cheek stripe! Thanks!

  • 19 years ago
    last modified: 11 years ago

    That's the key, Kate. If it's a Florida cottonmouth, whether it is a brightly colored juvenile or a nearly-black adult, that cheek stripe is present and very visible.

    I personally think the biggest danger with cottonmouths is stepping on one. Most snakes try to get out of your way, if they see or hear you coming. But water moccasins tend to lie in the middle of a path and not move when someone comes walking by. They may gape that white-lined mouth at you while staying put, but if you don't see the snake, you run the risk of stepping on it and getting nailed. Other than that, I've never seen them be any more aggressive than any other snake, though others may have had different experiences than I.

    Marcia

  • 18 years ago
    last modified: 11 years ago

    Thank you Marcia for the info.
    We are almost finish cleaning out the pond.Build-up of ten years of debris and muck. Well we have seen a small black snake swimming everyday. The other day my older son,Jeremy,
    30 years old,ran out of the pond scared. He said the "little"
    snake was swimming toward him. I told him him that it is a harmless snake. Thanks to you I know what to look for.

    Felix

  • 18 years ago
    last modified: 11 years ago

    You are welcome, Felix. I also did ID posts on coral snakes and diamondbacks, and every now and then, I get a question bumping those posts back up again. I never finished the one on pygmy rattlers, the only other venomous snake for us in central Florida. Someday, I'll get to that one, I imagine. It's good for gardeners to know when to be careful around a snake in the yard. We have more opportunities to run into them than many folks do, so we should certainly be able to identify the ones packin' "heat!"

    I'll be your pond is looking good!

    Hugs,
    Marcia

  • 18 years ago
    last modified: 11 years ago

    Thanks very much, Marcia. We live very close to water, and I hope I never see one. However, if I do, this will be very useful in identifying it.
    Lynne

  • 18 years ago
    last modified: 11 years ago

    great info marcia. i live on a small lake and i'm always bailing water out of it. luckly, i've only come across one big black snake. Knock on wood, i've never come across a cottonmouth...

    -Chris

  • 18 years ago
    last modified: 11 years ago

    Lynne, you are just the type person I had in mind when writing this...someone with a likely moccasin habitat nearby, who might see one while working in the yard.

    Chris, just remember that contrary to popular legend, they don't "chase" humans at all. But they often will lie still or stand their ground, rather than immediately seeking to retreat, like most snakes. And that is what makes them more dangerous, to my mind. Just be alert when around water, and you should be okay.

    Glad this post might be of help!

    Marcia

  • 18 years ago
    last modified: 11 years ago

    When I was fishing the Military Bass Anglers circuit here in Florida (many years ago smiling) we would run across them on a weekly basis. As Marcia stated, they don't chase you, but they don't give ground very easily and are the most aggressive snakes I've had the displeasure of dealing with. Mean critters that you learn "very quickly" to leave alone. Thanks for what youÂre doing to educate the citizens of Florida.

  • 18 years ago
    last modified: 11 years ago

    You're welcome, Tampaart. I think of them as being "passive-aggressive" in that they just stay put and DARE you to step on them or get too close. It's like they are saying, "I was here first, bud. Find another path, or go HOME."

    Marcia

  • 18 years ago
    last modified: 11 years ago

    Marcia,

    Passive aggressive is the perfect description!

    I really like the picture of the 9th cottonmouth down because I have been acquainted with that very snake at that very location in the wild. I was there with the photographer, a friend of mine, when that picture was taken. Small world :-).

  • 18 years ago
    last modified: 11 years ago

    WAYNE! Where you been, my little herp-lovin' buddy?? I've really missed your input whenever snake topics come up around here! How's the herpin' in MO right about now? Still too cold? I saw my first black racer of this season strectched out along the top of my plumbago, basking in the sun, Sunday.

    Glad you like the "passive-aggressive" term. And I remember you telling me about that snake before. It was a little guy in shallow water, right? I think you showed me a picture of your friend, standing in the water taking the picture. It's a GREAT shot of a beautiful snake.

    Good to see you! Hope you'll drop in more often.

    Marcia (Wish the reptile forum was more active. Whenever I drop by there, I just fine old posts sitting there unanswered, and nobody around to play with!)

  • 18 years ago
    last modified: 11 years ago

    Marcia,

    It's mostly still too cold in Missouri but I saw my first snake of the year about the same time you did. It was a large black rat snake just coming out of its den last Saturday. Pretty soon they'll be out in good numbers here. I'm sure the reptile forum will start to pick up in the spring too.

    Yeah my wife took the picture of the guy standing in the water at the same time he was taking the 9th picture down.
    I'm sure the snakes will start appearing in gardens more frequently soon and your educational posts to fellow gardeners will be a big help as always.

  • 18 years ago
    last modified: 11 years ago

    Hi, Marcia!
    I took this shot yesterday and despite your wonderful lesson I am not sure who they were. It was 3 of them (having a good time lol) near small freshwater lake.
    Maria



    {{gwi:884847}}

  • 18 years ago
    last modified: 11 years ago

    Maria, these look like harmless Florida banded watersnakes to me. Here's a picture for you to compare.

    Keep in mind that there can be a lot of variation in color, with some snakes being darker overall than others, and some being a bit brighter. But the general markings look the same to me, and you can see that the snakes do not have that wide brown cheek stripe. Nor are they anywhere near as heavy-bodied and thick as moccasins. These little guys are often thought to be dangerous when they aren't at all.

    Great picture, btw. I wonder if they are in mating mode right now? Seems a bit early in the year to me, but I'm not an expert on that. Wayne, are you still around?

    Marcia

  • 18 years ago
    last modified: 11 years ago

    Good call Marcia! Most definitely Florida Banded Water Snakes! Harmless and very frisky :-). Not too early for them to get frisky. Spring has sprung.

    Great picture by the way Maria! Looks like two frisky males and one female.

  • 18 years ago
    last modified: 11 years ago

    That's just what I was thinking, Wayne. Thanks for giving us the benefit of your MUCH MORE expert opinion. I have seen garter snakes doing the Group Romp thingie during mating season, and black racers, as well, but not these guys. However...snake friskiness must look pretty much the same in any species, I reckon. I mean, how much can they get up to with the No Arms Or Legs thing hampering them?
    *vgb*

    Marcia

  • 18 years ago
    last modified: 11 years ago

    FL newbie here who lives on a lake. Thank you ALL.

  • 18 years ago
    last modified: 11 years ago

    Hi, Doc dot! Hope this will give you peace of mind when you spot a harmless water snake swimming by. It pays to know the 4 venomous snakes we have here in central Florida (cottonmouth or water moccasin, eastern diamondback rattlesnake, pygmy rattlesnake, and eastern coral snake) so that you don't have to panic every time you see another type in the garden or on the lake.

    Glad this has helped you.

    Marcia

  • 18 years ago
    last modified: 11 years ago

    BUMP!

    Marcia

  • 18 years ago
    last modified: 11 years ago

    Thank you!! So helpful :)

    Cathy

  • 18 years ago
    last modified: 11 years ago

    You are welcome, Cathy. Hope you saw the one on coral snakes. I bumped it up, but it is already falling down, down, down! ;o)

    Marcia

  • 17 years ago
    last modified: 11 years ago

    Bump!

  • 17 years ago
    last modified: 11 years ago

    That is one grumpy cottonmouth! LOL
    Please...........keep'm in your yard...J/K Miss Marcia.

    *Wavin' to Wayne!!!! :)

  • 17 years ago
    last modified: 11 years ago

    Thanks for the wave :).

    Next month I'll be going on my annual fall cottonmouth watching excursion! Yay!

  • 17 years ago
    last modified: 11 years ago

    Hey, Wayne! Take pictures, PLEEZE! Especially if you go to that road where the migration occurs. Fascinating stuff!

    Marcia

  • 17 years ago
    last modified: 11 years ago

    Fabulous tutorial, thank you so much for the post, Marcia.

  • 17 years ago
    last modified: 11 years ago

    I know that generally cottonmouths are not aggressive. Once when i was a teenager we lived in Bithlo. Had a lot of rains so our ditches out front were full with water. There was one in the ditch and my mom was gardening. I was up at the house. I was coming out to tell my mom about the snake but then it started on a beeline straight for her. Was the strangest thing I ever saw. Well, I had to grab my pellet gun and take it out because I was afraid it would get my mom. I was amazed at how I shot it in the head from about 100 feet away though. I told my mom about it because she heard me shoot my gun and she was almost mad that I was shooting out front. I've never seen one aggressive since though.

  • 17 years ago
    last modified: 11 years ago

    any body know if the cottonmouth can be found in the canals off of the Banana River and Merritt Island? The water is salt water.

  • 17 years ago
    last modified: 11 years ago

    For the last thirty years, there are two times a year you'll find me wandering in the swamps: Fall archery deer season (Sept.& Oct.), and Spring turkey gobbler season (March & April).
    Since the weather is warm during those hunting seasons, I run into snakes of all sorts every single day. The cottonmouths and rattlers will merely lie there, coiled up and waiting to see what I'm going to do. I just walk around them.
    About twenty years ago I was driving back to my campsite down a dirt road in the Green Swamp WMA just after dark, when my headlights revealed the black, glossy form of some animal lying in the road about a hundred yards ahead. It was giving off a red eyeshine and at first I thought it was a freshly road-killed otter.
    As I got closer I realized I was looking at the biggest cottonmouth I'd ever seen. This thing was at least six feet long and as big around as my bicep.
    Although I had a shotgun in the truck, I had no interest in killing it. I did, however, want a photo.
    So, I grabbed my camera and walked up to the snake in the glare of the truck's headlights. It just lay there, all relaxed, not coiling or reacting in any way.
    This would never do! I wanted a ferocious gaping display!
    So, I kicked sand in its face a couple of times to get it riled up. It reacted by merely turning and slithering back into the heavy roadside brush.
    Talk about a cool character! I never did get a picture of it.

  • 17 years ago
    last modified: 11 years ago

    Brute,

    Great story and pretty consistent with what I often find. I've encountered an occasional aggressive one but I have encountered many more like the one you describe.

    Floridafarmer,

    Yes, In fact cottonmouths are fairly common at Merritt Island. All things being equal they probably prefer swampy freshwater but they can be found in saltwater estuaries and canals.

    Marcia,

    I will take some cottonmouth pictures next month! Pictures 7, 8 and 9 down were taken at the famous snake migration road.

  • 17 years ago
    last modified: 11 years ago

    You guys demonstrate my theory that cottonmouths are "passive-aggressive." Dangerous in that they don't move out of the path, often, and people who are not alert can step on them. Tales of them chasing people are usually highly exaggerated. This isn't to say it can't happen. Just that it's not a common behavior.

    My best cottonmouth story involved canoeing by myself on Rock Springs Run. I was in an area we call the Flats. Very shallow water, with a lot of grassy vegetation. Makes for slow canoeing as you try to glide through without digging up the bottom. I spotted a cottonmouth in the water, about 2 1/2 feet long, and close to the shore. It had a dead fish in its mouth. I don't think it killed the fish, but I can't be sure of that. But the fish looked REAL dead. It was a panfish of some type (bluegill, shellcracker, one of those) and quite wide, and this snake was trying its best to figure out how to swallow it.

    The snake worked its mouth slowly around the body of the fish, which was way, WAY too wide for it to swallow, and even tried to force it down sideways. The fish was probably ten inches long and no way was that snake going to get it down sideways. I let the canoe drift over fairly close, as I was enjoying the show.

    The snake finally began working its way towards the head of the fish, where it would have had the best chance to get it down, but suddenly noticed me or my canoe slowly nearing. If snakes could change expression, this one's eyes would have bugged out and his mouth would have dropped open. If they could talk, he would have been yelling "Holy Sheepdip! Where'd THAT come from??" He did a backflip away from the fish and took off for the weeds like a streak! It was so funny looking, I almost fell out of my canoe laughing at him.

    I always wondered if he came back later to finish working on the fish. But I didn't wonder about who was more scared by our encounter. He definitely was!

    Still...I am very careful on the river or in places where cottonmouths might lurk. They normally don't care if you approach them. I admire them, but I don't want to step on one or come face to face with one at any closer range than what I just described. I'm not NEARLY as brave as Wayne!

    Marcia

  • 10 years ago

    Thanks for this forum! I was trying to identify a dead snake by my mailbox near a ditch. We live on marshfront property and haven't seen hardly any snakes but a black racer. This year it's rained a lot and the ditches are full to the max! I think the snake was a water moccasin based on its triangular head and short tail. The eyes were eaten out already by some ants. My husband threw it away before I learned to check the side cheek stripes and neither one of us plan to dig it out of the trash. I'm assuming the rain is what drove it to us. Isn't it rare for moccasins to habitat in brackish water (in a marsh).

  • 10 years ago

    We don't have those snakes in California, but this is the saddest song I ever heard. Nobody ever wrote one about a rattler: https://www.youtube.com/watch?v=TiuGcBYdAPA

  • 10 years ago

    The photo with the guy holding the snake with a snake hook worries me. It's obvious from the cloudy eyes the snake just ate but I still don't think it's a very good idea to be handling a venomous snake without having its head under control. If threatened this snake could still bite him. My friends at the hero dept at the zoo where I worked years ago would say this is not a smart thing to do.

  • 3 years ago

    Thanks Carol! The search worked.


    Bump!