There are approximately thirty species of rattlesnake, with numerous subspecies. They receive their name for the rattle located at the end of their tails. The rattle is used as a warning device when threatened. The scientific name Crotalus derives from the Greek. Most rattlesnakes mate in the spring. All species give live birth, rather than laying eggs. The young are self-sufficient from birth. Since they do not need their mother after birth, the mother does not remain with her young. However, at least one captive study has demonstrated that females and their neonates show some level of affinity for each other's company and will cross barriers to reunite if separated.
Contrary to popular myth, rattlesnakes are not deaf. In fact, the structure of their inner ears is very much like that of other reptiles. They do, however, lack external ears. Sound (whether from air or ground vibration) is transmitted to the snake's inner ear via vibrations in other body structures.
Rattlesnakes are native to the Americas, with the large majority of species in the American Southwest and Mexico. The state of Arizona in particular has more species than any other state. Four species may be found east of the Mississippi river, and only 2 in South America.
Rattlesnakes consume mice, rats, small birds and other small animals. They subdue their prey quickly with a venomous bite as opposed to constricting. The venom will immediately stun or kill typical prey. Rattlesnake venom can kill in 20 seconds, but a rattlesnake will follow prey that does not quickly succumb to the venom and attempts to escape. Rattlers are known to strike at distances up to two-thirds their body length.
Although many kinds of snakes and other reptiles are oviparous (lay eggs), rattlesnakes are ovoviviparous – the female retains the eggs in her body and they hatch as they are laid or soon afterwards; or viviparous (give birth to live young). Baby snakes are ready to go as soon as they are hatched or born. There is little to no parental care of the newborn snakes.
The rattle is composed of a series of nested, hollow beads which are actually modified scales from the tail tip. Each time the snake sheds its skin, a new rattle segment is added. They may shed their skins several times a year depending on food supply and growth rates. Newborn rattlesnakes (pre-button) do not have functional rattles; it is not until after they have shed their skin for the first time that they gain an additional bead, which beats against the first bead, known as the button, to create the rattling sound. Adult snakes may lose their rattles on occasion, but more appear at each molting. If the rattle absorbs enough water in wet weather, it will not make noise.
Safety and identification
Different species of rattlesnake vary significantly in size, territory, markings, and temperament. If the rattlesnake is not cornered or threatened, it will usually attempt to flee from encounters with humans. Bites often occur when humans startle the snake or provoke it. Those bitten while provoking rattlesnakes have usually underestimated the range (roughly two-thirds of its total length) and speed with which a coiled snake can strike (faster than the human eye can follow). Heavy boots and long pants reinforced with leather or canvas are recommended for hikers in areas known to harbor rattlesnakes.
Guides are available through booksellers, libraries, and local conservation and wildlife management agencies that aid hikers and campers in identifying rattlesnakes. The advice given is to avoid contact with rattlesnakes by remaining observant and not approaching the animals. Hikers are advised to be particularly careful when negotiating fallen logs or boulders and when near rocky outcroppings and ledges where rattlesnakes may be hiding or sunning themselves. However, snakes will occasionally sun themselves in the middle of a trail, so such areas are not the only places where they are encountered. When encountering a rattlesnake on a trail, hikers are advised to keep their distance and allow the snake room to retreat.
Rattlesnakes are born with fully functioning fangs capable of injecting venom and can regulate the amount of venom they inject when biting. Generally they deliver a full dose of venom to their prey, but may deliver less venom or none at all when biting defensively. A frightened or injured snake may not exercise such control. Young snakes are also dangerous, and should not be treated with any less caution than the adults.
Most species of rattlesnakes have hemotoxic venom, destroying tissue, degenerating organs and causing coagulopathy (disrupted blood clotting). Some degree of permanent scarring is very likely in the event of a venomous bite, even with prompt, effective treatment, and a severe envenomation, combined with delayed or ineffective treatment, can lead to the loss of a limb or death. Untreated rattlesnake bites, especially from larger species, can be fatal. However, antivenom, when applied in time, reduces the death rate to less than 4%. It is estimated that between 7,000 and 8,000 people are bitten by venomous snakes in the United States each year, and about five of those die. About 72% of those bitten by rattlesnakes are male.
Some rattlesnakes, especially the tropical species, have neurotoxic venom. A bite from these snakes can interfere with or shut down parts of the nervous system. In the U.S. the Mojave Rattlesnake (Crotalus scutulatus) in Arizona and parts of California has a neurotoxic venom component known as Mojave Type A toxin. The current antivenom, (FDA-approved in October, 2000) known as CroFab, contains antibodies to Mojave A and B toxins as well as the toxins of most other U.S. pit vipers. Mojave A toxin has been identified present in the venoms of other species of rattlesnakes on occasion. Neurotoxins cause neurological symptoms, paralysis, and could result in death due to respiratory paralysis.
When a bite occurs, the amount of venom injected cannot be gauged easily. Symptoms and swelling may occur within minutes and potentially become life-threatening rapidly, but in some cases hours may pass before serious effects appear.
Experienced health workers typically gauge envenomation in stages ranging from 0, when there is no evident venom, to 5, when there is a life-threatening amount of venom present. The stages reflect the amount of bruising and swelling around the fang marks and the speed with which that bruising and swelling progresses. In more severe envenomation cases (stage 4 or 5) there may also be proximal symptoms, such as lip-tingling, dizziness, bleeding, vomiting, or shock. Difficulty breathing, paralysis, drooling, and massive hemorrhaging are also common symptoms.
Quick medical attention is critical, and treatment typically requires antivenin / antivenom to block the tissue destruction, nerve effects, and blood-clotting disorders common with rattlesnake venom. Most medical experts recommend keeping the area of the bite below the level of the heart. It is important to keep a snake bite victim calm in order to avoid elevating their heart rate and accelerating the circulation of venom within the body. Untrained individuals should not attempt to make incisions at or around bite sites, or to use tourniquets, as either treatment may be more destructive than the envenomation itself. Any bite from a rattlesnake should be regarded as a life-threatening medical emergency that requires immediate hospital treatment from trained professionals.
As an entrée
Rattlesnakes are a popular food in some southeastern and southwestern American cuisines and are sometimes sold in specialty meat shops. The flavor has been characterized by one vendor as "delicate" and "resembling chicken"; and by journalist Alistair Cooke as "just like chicken, only tougher."Others have compared the flavor to a wide range of other meats, including veal, frog, tortoise, quail, fish, rabbit, and even canned tuna.
There are fairly obvious risks with private ownership of rattlesnakes. A bite can cause death or permanent disability. Even a nonfatal bite can lead to very high costs for emergency medical care.Some jurisdictions outlaw the possession of venomous snakes. Where it is legal, some form of license or insurance policy may be required.