Northern Water Snake

Not being a snake expert I wonder if anyone can ID this snake from my

fairly poor descrition!

 

Location central/northern NJ. Brown snake, maybe 18" long, 1" diameter

at maximum. No stripes. Narrow darker bands (rings) around the body

every 2"

or so. No real coloration, just shades of brown. It looked like a

triangular head - at least the head was

certainly larger than the neck. Quite aggressive (I wondered

if it was dead so I lightly touched it with

a long branch and it immediately struck at it). Habitat - typical

lightly wooded area near a river with a few rocks around. It was lying

in the open (on bare ground in light rain!) near a pile of rocks.

 

Any guesses? I'm a little concerned given the triangular head

(indication of a venomous snake?) and the aggressive nature since it

was in an area where I didn't think there were any venomous species

and all the snakes I've previously encountered have been quite

timid.

No photo, Bob? What were you thinking? Snakes too primitive a life form to waste film on? ID'ing snakes from descriptions is always iffy, but my bet is that you had a species of <i>Nerodia</i>, probably <i>sipedon</i>, the northern water snake. I'm assuming by no real coloration you mean no obvious patterning; <i>Nerodia</i>s are real variable in the degree of pattern, from prominently banded to solid coloration. They can be aggressive when cornered, and like many harmless colubrid snakes, they can flare the rear margin of their skull and jaws when threatened to give their head a decidedly triangular appearance. They also bite and musk repeatedly if you're foolish enough to persist in your pestering of the poor little beast. Completely harmless though. You are within the range of copperheads, but they are usually prominently patterned, and a healthy snake 18" long would be decidedly bigger than 1" diameter at midbody. No cottonmouths where you are, and timber rattlesnakes are also usually boldly patterned and heavy bodied. That takes care of the venomous species in your area, I think - I'll be interested to hear the opinions of other ophidiophiles, but my bet's on a <i>Nerodea</i>. Oh, the fact that it was near water supports that diagnosis as well - might have just been emerging from a hibernaculum in the pile of rocks.

 

And next time, take a picture! In the case of snake ID's, it really is worth a thousand words.

Bob,

Can you differentiate whether the head, while somewhat triangular, was more spearpoint shaped or more pyramid shaped. One being more of a smooth transition from the body and the other a more abrupt change from the body. As it was agressive, did it open the mouth in any threat display so as to give you a look at coloration?

Water snake was my guess too. Is <a href="http://coloherp.org/geo/species/spenesi.html"> this</a> it?

Bob, I agree with Peter that this sounds like Nerodia. The water snakes, while harmless, can be VERY agressive. Growing up in Virginia this was the most common snake I encountered in my "snake-catching youth" and I had the displeasure of getting aquainted with the business end of its anatomy on several occasions. Fortunately, in that part of the state, cottonmouths (aka, water moccasins) are not found so I was relatively safe. Living in New Orleans now, I don't have that same luxury which makes positive IDs even more valuable. Your thinking that the snake was dead and then the aggressiveness you describe (I assume striking at you?) could also lead one to believe it was a hognose snake (g., Heterodon). They can "play dead" although it is usually after being provoked, as well as strike with the mouth closed. Coloration you describe could also indicate a hognose, but the they are much bulkier than 1" in diameter at 18" long. Take a look at Jim's picture, though, and you probably have your snake. Realize that when provoked the water snake will flatten its head into the triangular position you described (much more so than the docile looking specimen in the photo).

I am a herpetologst (actually ecologist working on herps) and I would venture to say that my fellow photo.netters have gotten it right. My bet is also Nerodia. Kudos to the above posters, their information is very good.

Thanks! The water snake sounds about right. I certainly would have taken its portrait if I'd had a camera with me, but of course I didn't. I may check out the area where it was though - and this time bring a camera! It struck with its mouth open. I'm sure if anyone had tried to pick it up (and I've seen people do that to snakes they didn't seem to know much about!) they would have regretted it. I quite like snakes, but mainly when observed from a respectful distance. I don't normally go poking them with sticks either, but this one looked like could have been dead. I don't usually come across snakes just lying on open ground (dirt, no grass) in the rain on cold days, but that's what this one was doing.

I live near the islands of the western basin of Lake Erie. We have a subspecies called the Lake Erie water snake located on some of these islands. If the northern water snake acts anything like the Lake Erie then it's best to leave it alone. It can be very aggressive. We had a guy up here at one of the state parks who tried to pick one up and it whacked him several times cutting him up pretty good. It's a really cool snake though and I believe it's on our endangered list now. But I wouldn't attempt to handle it.

Regarding Northern Water Snakes, yes they are extremely aggressive, and I belive they have a certain chemical in their saliva, while not posionous, is a very effective anti-couagulant. So if you do get bit, you will bleed quite a bit!

I am not aware of an anti-coagulation effect of the saliva of the Northern Water snake. It would seem that evolutionarily speaking, this would be of little use to the snake as they catch their prey and hold on to swallow, not bite, release and wait for the prey to bleed to death. Of course, I'm not a herpetologist so you may very well be correct. Maybe Ryan can answer this. I do know that I have been bitten quite a few times by this snake and experienced no prolonged bleeding.

I agree with the norther water snake determination. Young specimens

are often trim and boldly marked; older individuals get duller and can

be quite heavy bodied and impressively powerful. This time of year I

can find them draped over dead branches of trees which have partially

fallen into lakes and streams. Their M.O. is to drop into the water

when frightened, so if your canoe is right underneath they might

inadvertantly pay you a visit. When confronted they do get nasty as

you have seen. BTW, the conventional wisdom associating triangular

heads with venom is very often wrong. Many harmless species have

triangular heads, and several venomous species do not.

Most colubrid snakes have a functional Duvernoy's gland, a modified salivary gland, that is an active part of the prey capture, manipulation, and swallowing process. The venom gland of Viperids and Elapids is in many structural aspects similar to Duvernoy's gland, and may be homologous (evolutionarily derived from it). It is becoming more widely recognized by herpetologists that many, and maybe most, snake species that have classically been considered "non-venomous" produce Duvernoy's secretions with active enzymatic components that act in some manner to help subdue or otherwise impair prey. Harry Greene, an expert in the field of snake evolution, estimates that as many as half of the species of "advanced snakes" (which includes the majority of living species) produce venoms. The enzyme components of venoms and Duvernoy's gland secretions are complex and multifunctional - one common target of attack by venom components is the clotting mechanism of the prey organism. Other enzymes are strongly proteolytic (protein digesting), so even though they may not directly inhibit clotting, they might increase bleeding at the injection site. I'm not aware of any research on water snake Duvernoy's secretions per se, but I know of folks bitten by garter snakes, a closely related natricine colubrid, that have shown evidence of local hemolysis/proteolysis at the site of the bite suggesting they have active Duvernoy's gland secretions. I wouldn't be surprised if <i>Nerodia</i> is similar. Still, they are for practical purposes, "non-venomous", since the effect of even a severe bite to a human is slight and local. Because all colubrids have multiple rows of small but very sharp teeth, a fair amount of bleeding from multiple punctures is a typical outcome of most decent bites from medium- to large-sized colubrids. The best advice that anyone encountering an unknown snake can follow is simply to leave it alone. Snake bites, venomous are not, are almost always cooperative ventures reqiring participation of both the biter and the bitee.

A lot of non-venomous snakes have anti-coagulants, harmful/infectious bacteria, and/or other nasties...water snakes and rat snakes are some of the more common ones. Of course, their bites might have different affects on different people (just ask Bill Haast.)

Mine and Peter's responses must have passed each other in the photo.net server...btw, very nice Peter.

Thanks, Peter, for the clarification. It has been almost twenty years since my last herpetology course in college. At that time, the thought was that the mildy venomous rear-fanged species (as opposed such species as the African Boomslang)were the species that most characterized the modified salivary glands to begin digestion. Keith, I defer to Peter in support of your original post of the anti-coagulation effect of the saliva of Nerodia. And yes, Peter as a teenager it was most definately the actions of the bitee that contributed to my encounters. As I have gotten older and wiser, my encounters have not decreased but the consequences have. But, of course, this is a nature photography forum, so as not to digress too far from the topic...I saw your website Peter. Are you the photographer of the pigmy rattlesnake? If so, I assume you use maco equipment for your work. What setup do you use - 100 range or longer?

Rob,

 

Snake venom (broadly defined) is a hot field in herpetological and pharmacological research right now, and consequently generalizations about the topic are changing pretty constantly. I'll e-mail you off list with more details so as not to prolong this thread too much, but I've used either a 180 or 200mm macro lens for most of my snake shots.

 

Peter

What? No lawyer jokes?