Images thanks to www.flmnh.ufl.edu
Nomenclature
Crotalus horridus, Linnaeus, 1758
Timber rattlesnake, canebrake rattlesnake
The C. horridus was one of the first three species of rattlesnakes to be named. C. horridus was first discovered and named by Linnaeus in his Species Plantarum, that was published in 1758. Within the species, C. horridus, there are two subspecies, C. horridus atricaudatus and C. horridus horridus. This website focuses on the timber rattlesnake (C. h. horridus), as it is the one subspecies that is found in Connecticut. The canebrake rattlesnake (C. h. atricaudatus) is found further south, from Virginia to central Texas.
Appearance
The timber rattlesnake is a large, heavy-bodied rattlesnake, that can attain a length of about 3.3 feet and up to 6 feet in extreme cases. The color varies from yellow to black, depending in part on age (timber rattlers tend to darken as they age) as well as the specifics of their habitat. Timber rattlers found in damp, cool forests tend to be darker. Additionally, regardless of their color phase, the coloration nearer the tail becomes darker. Some timber rattlers also possess an orange-colored stripe running down their back, from head to tail. Although infrequent in timber rattlesnakes, the stripe is a characterstic of all canebrake rattlesnakes.
(Species description thanks especially to (Mattison, 110))
Habitat and Hibernation
The timber rattlesnake lives in rocky, hilly regions, sometimes at very high altitudes, and spends much of its active life on the surface among the shelter of grass, shrubs and ground litter. The timber rattlesnake, however, spends over 7 months of the year in hibernation in the Northeast. Timber rattlesnakes form dens of up to 200 individual snakes in rocks or animal dens in order to hibernate. The further north the timber rattlesnake lives, the longer time it will hibernate as the weather stays colder, longer and insufficient heat is available to the timber rattlesnake to lead an active life for much of the year. Because timber rattlesnakes (as are all snakes) are ectothermic, cold-blooded, they are unable to produce sufficient body heat. In order to maintain a desirable body temperature, snakes must rely on body heat exchange with their surroundings. Since snakes need to bask in the early morning or late day sun in order to establish a satisfactory body temperature, the longer the winter in an area (and thus less sunlight and colder temperatures), the longer time a timber rattlesnake will have to hibernate. (Rubio, 71-72)
Reproduction
Both male and female timber rajhttlesnakes have reproductive cycles, that is, a fertile period in which copulation is possible. However, these periods vary depending on the climate and the length of time during the year in which the timber rattlers can lead active lives. Timber rattlesnakes, as are all rattlesnakes, are viviparous and timber rattlers give birth to some 6-10 live young in a litter. Gestation is very stressful on the female, as the young must fully develop inside of her, and thus a female may only be able to recover from each litter in time to reproduce every few years. An interesting fact about female timber rattlesnakes is that long-term sperm retention has been reported. That is, the male snake's sperm can remain viable and stored within the female's oviduct for several months if necessary to better ensure the survival of the young. For example, if two timber rattlers mate shortly before their hibernation period, the sperm can remain in the female without fertilizing any eggs until the spring, when the young have a better chance for survival.
Eating Habits
In the wild, the timber rattlesnake's diet consists of small mammals, although the timber rattler has a high venom yield (third most among rattlesnake species), that can be fatal to humans. Timber rattlesnakes, along with all other rattlenakes and close relatives are known as pit-vipers because of nostril-appearing pits on either side of the head that are used to detect radiant heat. These pits are very sensitive and timber rattlesnakes use them to determine the exact location of their prey. The venom is injected into the prey throw two long, curved and hollow fangs that are attached to the maxilla bone in the top of the mouth. The fangs can swing back and forward as needed but fit into sheaths when not in use. Each fang is connected to a venom gland on the either side of the top half of the mouth. Timber rattlesnakes catch their prey by means of ambush. Timber rattlesnakes use their senses to locate oft travelled trails of small mammals and then wait for potential prey to approach. After striking its prey, the timber rattlesnake waits for the venom to take effect. The venom begins the digestive process by breaking down the prey's systems causing them to collapse within minutes of being injected with the timber rattler's venom. The prey may wander quite far from where it originally struck, but the timber rattlesnake tracks the prey, once it has collapsed, using its Jacobson's organ. The Jacobson's organ, common to all snakes and to monitor lizards (Varanidae), is a chemical sensor for which the tongue is the sensory apparatus. The Jacobson's organ provides a combination of smell and taste for the timber rattlesnake. The timber rattlsnake eats its prey whole, swallowing the head first. Because of several skull-joint modifications a timber rattlesnakes can open its ouths to swallow prey much larger its own head. The skin on a timber rattlesnake (and all snakes) is very flexibile and resilient, enabling it to stretch with the incredible head distention. After the prey is inside the timber rattlesnake's mouth, the snake proceeds to swallow the prey by using the teeth on alternate sides of the mouth to pull the prey further and further into the mouth, until final contractions of muscles in the neck deliver the prey to the stomach.
Range and Future Outlook
The timber rattlesnake has a wide range and is found in the north-eastern and north-central United States. It is currently found in 27 states. The timber rattlesnake is, however, only found in the United States but its numbers have seen a sharp decline in recent years in New England as a result of loss of habitat by human expansion. The timber rattlesnake has been listed as a threatened or endangered species, and thus protected, in Connecticut and 7 other states. As well as habitat loss due to human expansion in its territory, the timber rattlesnake has suffered serious population decline out of people's fear, leading many people to kill any timber rattlesnake (or any snake for that matter) that they may come across. Rattlesnake roundups, which have been around in the United States since 1934, kill some 5000 rattlesnakes at about 30 promoted roundups every year. There has been a recent and dramatic increase in the number of protestors against rattlesnake roundups, headed by herpetolgists and conservationists, that may hopefully put an end to the annual slaughter of rattlesnakes that has led to a sharp decline in the number of rattlesnakes in the United States, especially species like the timber rattlesnake that has seen its range severely limited in the last decades.
(Range and Future Outlook thanks especially to (Rubio, 149-151, 198))
Shaded areas indicate the range of the Timber Rattlesnake (C. h. horridus)
Links to other Timber Rattlesnake sites
Yale's CT Herps Home Page Link
Bibliography
1. Frank, Norman, and Erica Ramus. Complete Guide to Scientific and Common Names of Reptiles and Amphibians of the World.
Pottsville, PA: Reptile & Amphibian Magazine, 1996
2. Mattison, Chris. Rattler! A Natural History of Rattlesnakes.
London: Blandford, 1996.
3. Rubio, Manny. Rattlesnake: Portrait of a Predator.
Washington DC: Smithsonian Institution Press, 1998.