| Crotalus horridus is a venomous pitviper species found in the eastern United States. No subspecies are currently recognized. This is the only rattlesnake species in most of the populous northeastern United States and was featured prominently in the American Revolution, specifically as the symbol of the first Continental Navy in the First Navy Jack. | |||||||||||||||||||||||||
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Common names; Timber rattlesnake, banded rattlesnake, American viper, bastard rattlesnake, black rattlesnake, canebraker, cane rattler, canebrake rattlesnake, canebrake rattler, chevron rattler, common rattlesnake, common (timber) rattlesnake, eastern rattlesnake, great yellow rattlesnake, mountain rattlesnake, mountain timber rattler, North American (horrid) rattlesnake, northern banded rattlesnake, northern rattlesnake, rattlesnake of the bottomlands, rock rattlesnake, Seminole rattler, small rattlesnake, swamp rattler, southern banded rattlesnake, velvet tail, velvet-tail rattler, yellowish brown rattlesnake, yellow rattlesnake. |
Canebrake Rattlesnake - Crotalus horridus atricaudatus
Photo taken at the Jacksonville Zoo - Florida |
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Canebrake Rattlesnake - Crotalus horridus atricaudatus
Photo taken at the Jacksonville Zoo - Florida |
Description:
Adults usually grow
to an average length of 91-152 cm (35.8-59.8 in). The maximum reported
length is 189.2 cm (74.5 in) (Klauber, 1956). Holt (1924) mentions a
large specimen caught in Montgomery County, Alabama, that had a total
length of 159 cm (62.6 in) and weighed 2.5 kg (6.7 lb).
The dorsal scales are keeled and arranged in 21-26 scale rows at mid-body (usually 25 in the south and 23 in the north). The ventral scales number 158-177 in males and 163-183 in females. Males have 20-30 in males subcaudal scales while females have 15-26. The rostral scale is normally a little higher than it is wide. In the internasal-prefrontal area there are 4-22 scales that include 2 large, triangular internasal scales that border the rostral, followed by 2 large, quadrangular prefrontal scales (anterior canthals) that may contact each other along the midline, or may be separated by many small scales. Between the supraocular and internasal, only a single canthal scale is present. There are 5-7 intersupraocular scales. The number of prefoveal scales varies between 2 and 8. Usually the first supralabial scale is in broad contact with the prenasal scale, although slightly to moderately separated along its posteroventral margin by the most anterior prefoveals. |
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| Geographic Range: The range of the timber rattler extends from southern New Hampshire south through the Appalachian Mountains to northern Georgia and west to southwestern Wisconsin and northeastern Texas. Populations were once found on Long Island and in most mountainous and hilly areas of New York State, except in the higher elevations of the Adirondacks, Catskills and Tug Hill region. They are now found in isolated populations in southeastern New York, the Southern Tier and in the peripheral eastern Adirondacks. |
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Photo taken at the Jacksonville Zoo - Florida |
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Photo taken at the Riverbanks Zoo - S. Carolina |
Conservation
status: This
species is classified as Least Concern (LC) on the IUCN
Red
List of Threatened Species (v3.1, 2001). Species are listed as such
due to their wide distribution, presumed large population, or because it
is unlikely to be declining fast enough to qualify for listing in a more
threatened category. The population trend is down. Year assessed: 2007.
It is also listed as threatened or endangered in 18 states. It is endangered in Indiana, New Jersey, and Ohio, threatened in Illinois, Minnesota and Texas, and protected in Wisconsin and Massachusetts. In May 2001, the Canadian Species at Risk Act listed it as extirpated in Canada. Numbers have declined largely due to a history of bounty hunting and collecting (in the past). Today, loss of habitat is the primary concern over declining populations in several states protecting the species. Environmentalists in the New Jersey Pinelands have fought development in rattlesnake sanctuaries. A controversy over the species in Evesham Township, NJ, was the inspiration for the 2006 novel, "Rattled," by Debra Galant (St. Martin's Press). |
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Habitat: Generally, this species is found in deciduous forests in rugged terrain. During the summer, gravid females seem to prefer open, rocky ledges where the temperatures are higher, while males and non-gravid females tend to spend more time in cooler, denser woodland with a more closed forest canopy. Although rocky forested hill-sides with southern exposures are essential as winter habitat, rattlesnakes prefer dense forests with a thick under story for foraging. They bask during the day and forage at night, when prey is most abundant.
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Photo taken at the Riverbanks Zoo - S. Carolina |
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Photo taken at the Riverbanks Zoo - S. Carolina |
Behavior:
When
threatened, they vibrate their tails to produce a loud buzzing sound
that is difficult to miss. They are not particularly aggressive and
bites are rare. Adults shed their skin every one or two years, with the
average being every 1.4 years. A new rattle segment is added each time
shedding occurs. Snakes with a complete set of rattles are rarely seen,
however, since the rattles regularly break off. Contrary to popular
opinion, a rattlesnake will not pursue or attack a person unless
threatened or provoked. Males are sexually mature in 5 years, females in
7-11 years. Their average life span is 16-22 years, with a maximum age
of about 30 years. During winter, dozens of timber rattlers may
congregate together in a den to hibernate below the frost line in
association with copperheads (Akgistrodon contortrix), other
snakes, and skinks (Eumeces spp.). Dens are generally on open,
steep, south facing slopes with rock fissures or talus surrounded by
hardwood forests.
Male timber rattlesnakes engage in a special "combat dance" when they encounter each other, especially if a female is near. The males face each other with their heads and forward part of their bodies raised. They intertwine their necks, each trying to push the other to the ground to establish superiority. |
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| Feeding: Their prey is mainly small mammals, but may include small birds, frogs, or other snakes. Rattlesnakes prey on a variety of warm-blooded animals, including: mice, chipmunks and other squirrels, rabbits, shrews, moles, weasels and birds. Occasionally, rattlesnakes will also feed on insects, amphibians and other snakes. Timber rattlesnakes hunt and feed less than twenty times during the summer. They are secretive in their summer activities, hunting at night and remaining inactive and out of sight for days at a time during the digestive period after eating a squirrel or small rabbit. Without predators like the rattlesnakes, the world would soon be overrun with crop-eating, disease-carrying rodents such as mice and rats. |
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Photo by; J.L. Gingerich D.V.M. |
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Reproduction: Mating usually occurs in summer or fall. Females incubate eggs within their bodies by basking, and give birth the following year to 6-10 young from mid-August through September. Female rattlesnakes typically give birth every two or three years. Timber rattlesnakes are long-lived, late-maturing and slow-reproducing animals that have relatively short activity periods during a given year. The low reproductive output and low turnover in populations make the timber rattlesnake very susceptible to extremely low exploitation levels. Mating occurs in the spring and fall. Males are especially active at this time, seeking out females by following the pheromone (sex attractant odor) they emit. The gestation period is 4-5 months. Females give birth to 4-14 (average 9) young every three to five years during late August to mid-September. The young are approximately 1 foot (30 cm) in length at birth and emerge singly from the female, encased in a transparent membrane which is shed in a few minutes. Each is equipped with venom, hollow fangs and a tiny rattle segment called a "button." Their skin has a velvety texture and the coloring is essentially the same as the adult's. They remain in the area for 1-2 weeks before shedding their skin and dispersing. The young follow the adult's scent trail back to the den. Males are sexually mature in 5 years, females in 7-11 years. | ||||||||||||||||||||||||
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Photo by; J.L. Gingerich D.V.M. |
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| Taxonomy: The subspecies C. h. atricaudatus (Latreille in Sonnini and Latreille, 1802), often referred to as the canebrake rattlesnake, is currently considered invalid. | |||||||||||||||||||||||||
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Venom:
Potentially, this is one of North America's most dangerous snakes, due to its long fangs, impressive size and high venom yield. Fortunately, this is to some degree offset by its relatively mild disposition. Before striking, they often do a good deal of preliminary rattling and feinting. Cist (1845) described how he lived in western Pennsylvania for many years and that the species was quite common there, but that in all that time he heard of only a single death resulting from its bite. There is considerable geographic and ontogenetic variation regarding the toxicity of the venom; something that can be said for many rattlesnake species. Four venom patterns have been described for this species: Type A is largely neurotoxic and is found in various parts of the southern range. Type B is hemorrhagic and proteolytic and is found consistently in the north and in parts of the southeast. Type A + B is found in areas where the aforementioned types apparently intergrade in southwestern Arkansas and northern Louisiana. Type C venom has none of the above components and is relatively weak. The neurotoxic component of the Type A venom is referred to as canebrake toxin, and is a phospholipase A2. It is analogous to the neurotoxins found in the venoms of several other rattlesnake species and, when present, contributes significantly to the overall toxicity. Other components found in the venom include a small basic peptide that works as a myotoxin, a fibrinogen-clotting enzyme that can produce defibrination syndrome, and a bradykinin-releasing enzyme. CroFab antivenin, while not specific for C. horridus, is used to treat envenomations from this species. |
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