Reptile & Amphibian Forums

I live near Austin, Texas and this afternoon, my son scared a snake while mowing our back yard and it made a beeline for the swimming pool.

In the pool, it seemed quite at home, sometimes diving several feet under the surface and coming up at the other end of the pool. As I tried to get near it, it would again dive and head for the other side. Unfortunately, it was able to get out of the pool while I went in to get a camera so I have no pictures. It probably has a home under some large limestone landscaping rocks near the pool (there is a small cool cave there where our cat likes to hang out).

It's head appeared somewhat triangular in shape, but I have read that many water snakes can flatten out their heads and appear this way. Its back was a very dark green/brown with a series of double black lines across (laterally) its back each pair being about 2 inches apart and they did not reach all the way down its sides to its belly. I was unable to get a good look at its belly. It was about 30 to 36 inches long and slender (as compared to a western diamondback, which is one of the few snakes I am familiar with).

We are concerned that it might be a cottonmouth and will not be allowing our children or pets back there until we can identify it or have someone capture and remove it. Does anyone have any idea what this might be or know someone who would be willing to trap or capture it?

There are several good websites that cover Texas Snakes that have good photographs.

The immediate snake that comes to mind in the Diamondbacked Watersnake. I have attached a picture of it for you.

Other snakes to investigate would be Black-necked and Checkered Gartersnakes, and Blotched Watersnakes. All these species occur in the Austin area.

Try searching for the UT Natural History Museum herp website. I have put a link below -

UT Natural History museum Herp site

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Chris Harrison

Thanks for the info, Chris and b12rs. This has been a great learning experience. I'm now pretty sure it is not a cottonmouth, based on the non-agressiveness and the way that watersnakes and cottonmouths differ in the way that they swim.

I'm still not sure which type of watersnake it is, possibly blotched, brown or banded, but I'm not yet sure which of these inhabit this area. It is much darker than the photo of the diamondbacked watersnake. I've also learned that snakes change sometimes drastically from youth to adult and that even within the same species, coloration and markings can differ, thus one picture is not representative of all.

One final question, though. I have a young cat (little less than 1 year old) that likes to "hunt" in the back yard and has found that the "cave" behind the pool is a cool place to hang out. Do you think that this snake would pose a threat to him?

Thanks again.

Without much doubt, the snake is in more danger from the cat than vice versa.

I'm now pretty sure it is not a cottonmouth, based on the non-agressiveness and the way that watersnakes and cottonmouths differ in the way that they swim.

You can't safely tell cottonmouths from watersnakes by behavior. This is largely an old wive's tale.

Generally, when they aren't running away from you, Cottonmouth's do swim somewhat differently than Watersnakes, but not always. When they are pressed (trying to get away), I have seen both types swim on the surface and below the water. Furthermore, the difference in how they usually swim is subtle and takes a little experience to recognize.

Sometimes cottonmouths will "stand their ground". It isn't an act of aggression, rather it is a very defensive "God I hope they don't see me!" response. Only if you get very close will they even flash their mouth and they are actually much less inclined to bite than their non-venomous counterparts.

Generally a harmless watersnake will flee if approached, but not always.

My point is if you want to learn to tell venomous from non-venomous snakes, get a good book on Texas Snakes and study it. Shortcuts in identification lead to accidents.

Just for reference, I am not chastising you. You sound like a person who is wise enough to take the "leave them all alone approach", which is by far the best approach.

BTW - the common watersnakes in your area would be Blotched and Diamonbacked.

As to cats, my cats interact with snakes more often than most (due to the presence of snakes in my house for photography, etc) and the cats' ability to pull back from a striking snake is uncanny. There reflexes are amazing (and my cats are 12 and 14 years old). No need to worry about your cat vs. the watersnakes.
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Chris Harrison

A cotton mouth is relatively stocky and wide bodied, and will generally not fleet when startled.

I'll refer you to chrish's post for identification info.