Timber Rattler
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Name: Timber Rattler
Scientific name: Crotalus horridus horridus
Range: North Central to North Eastern U.S.
Habitat: forested, rocky hills
Status: Endangered, illegal to own or keep 
 Diet in the wild:rodents, hares, and birds 
Diet in the zoo: mostly rodents diet
Location in the zoo: Herpeterium
(Not currently on exhibit).
Physical Description
  • Heads are characteristically wide and spade-shaped, with rounded snouts
  • Body lengths have been recorded at over 1m (3ft 3in) long
  • Weight about 4.5 lbs

  • Ground color is gray or yellowish. Over this are a number of velvety black chevrons or crossbars. The background color becomes darker towards the tail and some forms of the timber rattlesnake are heavily suffused with black, making the markings difficult to see.

  • Rattle is a series of horny shells fitted loosely inside one another and are made of keratin. 

  • Tails of rattlesnakes are relatively short, perhaps to make it easier to vibrate its rattle. 

  • Males are heavier bodied than females.
  • Juvenile timber rattlers are marked like the adults. 
    General information:

    Image courtesy of  West Virginia Reptiles and Amphibians

    Timber rattlesnakes hibernate in den sites, and often spend several days in the spring basking near the entrance before they disperse. This is known as “lying out”. They will stay close to the den site until temperatures become warm. Pregnant females will usually remain around denning sites.  A second lying out period takes place in the autumn before they go down into the den, but this tends to be a shorter period.  In the east, timber rattlesnakes are the only species that form reasonably large dens, with over 200 members having been recorded at several locations earlier this century.

    Timber rattlesnakes are not a major threat to humans and livestock. Death due to a bite is unlikely. This snake has a secretive nature and prefers areas that are unused by humans. They remain quiet, and are often reluctant to rattle, preferring not to call attention to themselves.  However, timber rattlers will become defensive and bite if disturbed. They are capable of controlling the injection of venom when biting; up to 80% of all poisonous snake bites to humans contain no venom.

    Special anatomical, physiological 
    or behavioral adaptations:

     The feeding habits of rattlesnakes have been the driving force behind the evolution of their venom apparatus, and ultimately, the rattle. The rattle is the structure that sets rattlesnakes apart from all other snakes. It consists of a series of horny segments, which fit loosely inside one another. These segments are made of keratin, the same material that forms fingernails. The rattle has a covering which prevents it from coming away with the rest of the skin when the snake sheds. 

    Image courtesy of 
    West Virginia Reptiles and Amphibians
    Comments about the timber rattler of the Fort Worth Zoo: 

    Due to renovation, This animal is not currently on exhibit. 

    Personal Observations: 

    Due to the absence of the snake, it was not possible to make observations at this time. 

    Source Materials and Related Links:

    Matison, Chris. Rattler! A Natural History of Rattlesnakes. Sterling Publishing Co., Inc. 387 Park Avenue South, New York, NY 10016-8810.


    Page author: {short description of image}Sonia Smoak 
    Send E-mail to Lil1Smoak@aol.com

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