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Timber Rattlesnake

(Crotalus horridus)

Protected Wild Animal

 

 

 

Pictured above: Note the elliptical pupils, indicative of venomous snakes within Wisconsin (upper right).  Also note the black tail (lower left) and arrow shaped head (lower right).  Some of the pictures on this page are of a captive specimen legally owned by an employee of the DNR's Bureau of Endangered Resources for educational purposes.  It is absolutely illegal to for personal collectors to own this snake within Wisconsin.

        Description: Timber rattlesnakes are relatively large, with adults reaching lengths of 36 to 56 inches.  Their dorsal pattern consists of brown or blackish-brown cross bands, on a tan, rust or dark brown background.  The tail of these snakes are usually black and tipped with a rattle (pictured above), while the head is usually solid gold or tan in color.  They have no markings on their heads, unlike Wisconsin's other rattlesnake, the Massasauga.  All venomous snakes in Wisconsin have elliptical (cat's eye) pupils, and triangular shaped heads.

Unlike snakes that belong to the families Colubridae, Natricidae, and Xenodontidae, timber rattlesnakes use venom (a mixture of complex proteins) to subdue their prey.  Timber rattlesnakes are members of the family Viperidae, which includes vipers worldwide.  In addition, these snakes are members of the sub-family Crotalinae, which includes the "pit vipers", such as copperheads and cottonmouths (which do not exist in Wisconsin).  Pit vipers have heat sensing pits located just below either nostril that help them locate warm-blooded prey.  Within Wisconsin and Minnesota, timber rattlesnakes are one of only two venomous snake species (the other being the extremely rare Massasauga).

        Habitat/Ecology:  Timber rattlesnakes can be found in both rocky bluff habitats (where their over-wintering dens lie) and adjacent wooded lowlands (where foraging usually occurs).  Peak emergence from hibernation occurs in May, with some individuals emerging as early as late April (depending on temperature).  After emergence, many individuals remain near the den opening to bask before dispersing into the surrounding lowlands.  After dispersing, individuals usually hunt for a period of time, before searching out members of the opposite sex to breed.  Breeding is reported in late summer/early fall.  Males will "combat" each other over females, and this combat includes complex "dances" in which snakes appear to wrestle with each other for dominance.  After mating has occurred, the female is said to be able to hold sperm in her oviduct for extended periods of time (perhaps over the winter) and then fertilize her eggs the following spring.  Gravid females will then remain on the warmer bluffsides during most of the summer to incubate the developing young.  Timber rattlesnakes do not lay eggs, but instead hold their young internally until they develop to the point that they can be released (live birth).

Timber rattlesnakes return to their dens lat in September or October to hibernate.  These dens are usually deep rock fissures, that go below the frost line,  which are found along bluffsides.  These snakes are reported to den communally with other snake species.  Stories have been told of rattlesnakes dens in the past containing hundreds of individuals.  Now, however, due to human persecution, it is unlikely that so many timber rattlesnakes occur within a single area in Wisconsin.  It is interesting to note that it was once thought black rat snakes (Elaphe obsoleta) guided rattlesnakes to their dens for the winter.  Because of this false belief, black rat snakes were, at one time, referred to as "pilot snakes".

Timber rattlesnakes eat primarily rodents, and Vogt (1981) reports the stomach contents of 78 individuals to include deer mice, voles, gray squirrels and chipmunks.  On several occasions, I have found that if an area is full of chipmunks (and timber rattlesnakes are known to reside nearby) that these snakes will not be far away.  The fact that they eat deer mice is of particular value to humans, because this mouse can be involved in the spread of Lyme's disease.

These snakes hunt by use of both eyesight, and heat-sensing pits.  Unlike members of the family Colubridae, Natricidae, and Xenodontidae (which includes all the non-venomous snakes in Wisconsin), rattlesnakes do not actively hunt.  Instead, these snakes ambush their prey by remaining motionless and using their cryptic coloration to remain unnoticed.  In addition, timber rattlesnakes can be found in areas that rodents use as "runways".  For example; near logs or fallen trees.  When a rodent is presented with an obstacle that it cannot climb over (such as a large log), it will generally move along the side of the obstacle until it comes to the end, at which time it can go around the obstacle.  Therefore, timber rattlesnakes can sometimes be found waiting at the ends of logs, hoping that an unsuspecting mouse will come along soon.  This snake's tendency to remain motionless, it's cryptic coloration, as well as the fact that some humans like to hike "off of the beaten path", can increase the likelihood of human/rattlesnake interactions.

        Remarks:  The timber rattlesnake is the larger of Wisconsin's two venomous snakes.  Sometimes referred to as a "cane brake" or "velvet tail" in the south, these snakes are extensively (and wrongly) persecuted by humans.  Because they are rare and generally don't exist in areas that humans utilize often (such as deep woods and bluffsides), these snakes are generally not a threat to people or livestock.  However, the increased urbanization of bluffs and adjacent lowlands, as well as the tendency for some people to hike off the beaten path, can increase human/rattlesnake encounters.  When in areas that these snakes call home, always look where you are stepping or placing your hands.  To learn how to avoid rattlesnakes and what to do if you are bitten, click on the link below.

Despite their size, these snakes are not usually deadly.  In fact, Schorger (1967) estimated that of the 70 instances of timber rattlesnake bites in Wisconsin prior to 1880 (when medical treatment was not nearly as advanced as it is today), only 12 deaths were known to have occurred.  furthermore, during the 1900's only one timber rattlesnake-related fatality in humans was documented.  I have encountered these snakes on many occasions and never once have they taken an aggressive posture towards me unless I instigated it by attempting to get a closer look.

It is interesting to note that most believe the "rattles" on rattlesnake tails evolved thousands of years ago, when rattlers co-inhabited the landscape with many large grazing animals (such as bison).  It is thought that rattles were evolved to warn these larger animals to watch their step.

Timber rattlesnakes are my personal favorite snake in the state.  Their sleek appearance and beautiful colors makes them irresistible to anyone who love herps.  I have found them in several counties around the La Crosse area, although I will not divulge where for the fear of ignorant humans rooting them out and harming them.

Timber rattlesnakes signify the beauty and wonder of the natural world.  They are misunderstood and should be conserved.  If left alone, these snakes are harmless.  They will only bite if startled, or molested.  Attempting to kill a rattlesnake increases your chances of being bitten.  If you encounter one, call the proper authorities (see below).  They help control the rodents that damage crops and spread disease, and therefore are beneficial to humans.

If you have seen a rattlesnake or have encountered one near your home, contact the DNR by calling:

 1-888-74SNAKE

The Wisconsin DNR currenlty lists the timber rattlesnake as a "Protected" species.  Harming them can result in stiff fines exceeding several hundred dollars!

Want to know what to do if you have a run-in with a Timber Rattlesnake?  Click Here!

 

 

 

Can't get enough of Timber Rattlesnakes?  Me either!!!  I love 'em!  Call me strange (and I'm sure you will), but they are my favorite snake in Wisconsin.  If you're a Timber Rattlensake junkie, click here to see more pics!!

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