The Official Houston Zoo Blog

This is the last in our Snake Series written for you by The Houston Zoo’s Herpetology Department Supervisor, Judith Bryja.It’s been an incredible read!  Our Herp Department knows their stuff, and since we get so much interest in snakes, Judith is wrote this informative blog series each week just for you!  If you’d like to read the series from the beginning, click here.

Rattlesnakes and Texas: the words just sound right together don’t they?  While we do not have the most species of rattlesnake (that honor goes to Arizona) we can boast of 8 species (10 kinds if you go by subspecies). 

There are about 30 species of rattlesnake all together and they occur only in the Americas.  Baby rattlesnakes are born (live) with a single little “button” that does not rattle.  Every time the snake sheds (which is about 2-5 times a year depending on age and food intake) a new rattle segment is added to the tail.  Sound is produced as the rattle segments hit each other when the tail is vibrated.  Because the number of times that a snake sheds in a year’s time is variable, along with the fact that the rattles can break off, is why an accurate age of a snake cannot be determined by the number of rattles. Rattlesnakes come in many sizes from an adult length of about 15 inches all the way to about 8 feet.  Rattlesnakes are pitvipers (along with our local copperheads and cottonmouths and many other snakes around the world).  They have a very sensitive heat sensing pit on each side of the head between the eye and nostril.

While odds are you will never find a rattlesnake in Harris County you still might find one if you drive an hour or so out of town.  We look at 3 below.

One of the most well known rattlesnakes is the Western diamond-backed rattlesnake (Crotalus atrox) which is widely distributed across the southwestern U.S.  The closet to Houston that they occur is Galveston.  The record size is 7 ft, 4 in but average size is only 3-4 feet.  Color is variable but usually dark grey or brown with diamond shaped markings down the back (which can be faint in some specimens).  If you’ve heard the phrase “coon tail” applied to a rattlesnake this is because the tail has black and white alternating bands.  Diet is mostly mammals.  While there are definitely exceptions, these snakes in general tend to be high strung and easily provoked, rattling in a defensive posture with the front part of the body raised in an “S” shape.  Though if not further provoked or harassed they will usually slowly back away and calm down.  Most of the venomous snakebites that occur in Texas are from this species.

Western diamond-backed rattlesnake (Crotalus atrox)

Next is the rarely seen Western pygmy rattlesnake (Sistrurus milarius streckeri).  These little guys occur from east Texas to the east coast.  Adult size is only 15-20 inches and their rattles are so small they can barely be heard rattling from a few feet away.  Basically grey, they then have small dark spots going down the back and sides and usually an orange tinge running down the top of the back.  There are black lines on the head to the neck and also from the eye to the back of the mouth.  Diet is varied and includes, mice, reptiles, amphibians, and insects.

Western pygmy rattlesnake (Sistrurus milarius streckeri)

Last, we have a beautiful serpent-the Canebrake rattlesnake (Crotalus horridus atricaudatus).  This is a subspecies of the timber rattlesnake that ranges all the way up north where that strange thing called winter occurs.  This is our second biggest rattlesnake, averaging 40-60 inches.  Base color is usually tan or grey brown with dark brown or black crossbands running the length of the body. Overall color gets darker toward the tail.  A dark orange or pinkish stripe runs down the top of the back, fading the further it goes.  A wide dark brown stripe runs from the eye to the jaw.  Canebrakes like moist woodland/mixed pine forest and eat mostly mammals.  They are in general pretty laid back for a rattlesnake.  They are listed as “threatened” by the state of Texas.

Canebrake rattlesnake (Crotalus horridus atricaudatus)

Rattlesnake “roundups” are touted as fun and educational but are basically nothing more than organized persecution and slaughter.  Thousands of rattlesnakes are collected for some of these events only to be crammed together in small spaces and then have their heads chopped off for entertainment purposes.  Large scale collection/extermination of an animal such as the rattlesnake can throw all kinds of stuff out of balance resulting in things such as rodent overpopulation which brings its own problems.

S0-while you can definitely be hurt by a rattlesnake, your odds of dying from drowning or being struck by lightning and many many other things is waaay higer.  Snakes mostly just want to be left alone to go about their business and won’t bother you if you don’t bother them.  Surprise, surprise, most snakebites occur to people that are trying to kill or catch the snakes.

Written by Judith Bryja, Herpetology Department Supervisor

For more information on Texassnakes, Judith has reccomended these two resources: http://www.herpsoftexas.org/ and  The Field Guide to TX Snakes written by James Dixon and former Houston Zoo director John Werler.