Imagine you are out on a warm, breezy spring afternoon, climbing through dense chaparral deep in the Los Padres National Forest in California. You’ve been searching for hours through rocks and crevices, trying to find the elusive California mountain kingsnake (Lampropeltis zonata), when all of a sudden you hear that loud characteristic sound, tsssst, tsssssst, tsssssssssssssssst!
What goes though your mind next is a scattershot of emotions: excitement, because you feel like a school kid knowing there is a snake nearby; fear, as in, Oh crap, it’s a southern Pacific rattlesnake! Where the hell is it? followed by absolute joy when you are spot the rattler hiding below the ledge you are standing on, where it is nowhere near within striking distance. Most avid field herpers have encountered a similar situation, whether they are hunting for a specific rattlesnake or another species entirely. You always know a rattlesnake is probably nearby. Rattlesnakes are some of the most unique and diverse American reptiles. There are currently 32 different species of rattlesnakes, with approximately 83 subspecies that are broken down into the two genera Crotalus and Sistrurus. Such diversity exists between both groups of rattlesnakes because they are able to inhabit a wide variety of habitats, allowing for speciation to occur. This article will focus on some brief natural history of some of the more unique rattlesnake species in North America. For further reading, I recommend The Biology of Rattlesnakes by Hayens et al., Rubio’s Rattlesnakes of North America and Canada and Ernst’s Venomous Reptiles of the United States, Canada, and Northern Mexico. But now, let’s take a look at 11 of the more interesting North American rattlers. Timber/Canebrake Rattlesnake Dennis Riabchenko/Shutterstock Timber rattlesnakes are some of the more passive and slow-moving species of rattlesnakes. These used to be classified into two subspecies—the timber rattlesnake (Crotalus horridus horridus) and the canebrake (C. h. atricaudatus)—until scientists discovered that the two subspecies nearly had the same genetic structure. However, many individuals believe that the canebrake and the timber are two distinct species based off of clear morphological differences. Both are heavy-bodied, medium to large rattlesnakes. Their dorsal patterning includes dark chevrons with light edging scales. The chevrons darken as they reach the tail. These are some of the more passive and slow-moving species of rattlesnakes. Often they will not even rattle unless they are disturbed continuously. Their cryptic pattern allows them to blend exceptionally well with the vegetated ground cover. Timber (and canebrake) rattlers often remain undetected while buried in fallen leaves or grass with only their heads exposed. In the eastern U.S., the timber rattlesnake inhabits exclusively mountainous highlands consisting of deciduous forests, meadows and rocky hillsides.Although not an aquatic species, canebrakes occupy wetter environments along waterways, swamps and bogs within hardwood forests. In the southern U.S., they frequently are found in tall grasses related to bamboo, the reason for their common name.
Populations of both species are thought to be in rapid decline, and they are protected in some regions. Threats include habitat destruction, human development, agriculture, commercial collecting and unwarranted killing. Recently, the emerging infectious disease known as snake fungal disease (Ophidiomyces ophiodiicola) was described in a population of timber rattlesnakes, making this emerging infectious disease a concern to the species’ conservation status. Eastern Diamondback Averaging about 5 feet in length but with reports of specimens up to 8 feet, the eastern diamondback (C. adamateus) is the second longest rattlesnake and most heavily bodied in the U.S. It has the most distinct pattern of all the North American rattlesnakes, and the dark dorsal diamond pattern allows eastern diamondbacks to blend into their habitat extremely well. Being an ambush predator, the eastern diamondback relies heavily on this camouflage. Its range includes the coastal plain of the southeastern U.S., where specimens can typically be found in habitats containing two niches. First, eastern diamondbacks cohabitate with the gopher tortoise (Gopherus polyphemus), utilizing tortoise burrows for shelter during hibernation, birthing and predator evasion. Secondly, rotting wood stumps provide shelter for these animals through a network of root systems as a series of tunnels. Eastern diamondbacks typically feed on small mammals or quail. Few animals are predators to an adult eastern diamondback; however, bobcats, raptors, feral pigs and other snakes such as kingsnakes can consume the young animals. Western Diamondback The western diamondback rattlesnake (C. atrox) is the longest rattlesnake found within the United States, with the largest one ever recorded being 8.5 feet in length. On average they range from 3.5 to 4.5 feet. Like the eastern diamondback, it has a distinct diamond dorsal pattern; however, the western diamondback’s pattern is much lighter than the darker eastern diamondback’s. Colors can range from light tan to red depending on habitat. One distinct feature of these snakes are the four to six alternating black and white bands that are present before the tail turns into a rattle. When provoked, the western diamondback exhibits a brilliant anti-predator display, rattling consistently with a characteristic raised S-shaped coil, with body cocked and ready to strike. The western diamondback is responsible for envenomating more people than any other rattlesnake species in the U.S. Western diamondback rattlesnakes inhabit a wide variety of habitats because they are ecological generalists.Western diamondback rattlesnakes inhabit environments ranging from flat, arid regions of the southwest U.S. to mountainous rocky areas. In the wild, young western diamondbacks face predation from birds of prey, other snakes, roadrunners, and carnivorous mammals. Humans also pose a threat through habitat destruction for development, increasing interactions between humans and these snakes. Additionally, events like rattlesnake roundups have led to population declines and local extinctions due to excessive harvesting and hunting.
Approximately 125,000 western diamondback rattlesnakes are harvested annually for sensationalistic displays at rattlesnake roundups. These events are widely believed to have significantly contributed to population declines, especially in Oklahoma. While often presented as educational, roundups do not foster positive attitudes toward rattlesnake conservation and instead hinder it considerably. Mojave Rattlesnake Ryan M. Bolton/shutterstock The Mojave rattlesnake (C. scutulatus) is frequently mistaken for the western diamondback due to overlapping ranges and similar diamond dorsal patterning, with coloration varying from brownish to muted green. Two key features distinguish it: the tail banding pattern and facial stripes. The tail typically has two to eight alternating black and white bands before the rattle, with the top segment black and black bands narrower than white ones. For facial stripes, Mojave rattlesnakes have two white stripes running diagonally backward from the eye to the mouth scales, the first starting at the front of the eye and the second ending beyond the jaw angle. If envenomation from a Mojave rattlesnake occurs, it is considered a serious medical emergency. This species ranges from California to Texas in the southwestern U.S., with populations having different venom compositions. Experts categorize them into two types: Type A with the potent neurotoxin “Mojave toxin” and Type B with primarily hemotoxic venom. Some populations in central and southern Arizona possess both venom types, creating a life-threatening mix of hemotoxic and neurotoxic effects upon envenomation. Western Rattlesnakes The western rattlesnakes include five different subspecies, such as the southern Pacific rattlesnake (C.The western rattlesnake (Crotalus oreganus) includes several subspecies such as the southern Pacific (C. o. helleri), northern Pacific (C. o. oreganus), Grand Canyon rattlesnake (C. o. abyssus), midget faded rattlesnake (C. o. concolor), and the Great Basin rattlesnake (C. o. lutosus). These snakes were once thought to be related to the prairie rattlesnake (C. viridis), and many share similar dorsal markings and facial striping, making identification challenging. However, knowing their ranges and intergrade zones simplifies the process.
Western rattlesnakes thrive in diverse habitats, from conifer woods to vegetated coastal areas, and can be found at elevations from sea level up to 9,000 feet. They range from Mexico to Canada and west of the Continental Divide. The southern and northern Pacific rattlesnakes often intergrade along the central coast of California. The C. oreganus group is popular in the venomous pet trade due to its high color variation, including amelanistic, albino, patternless, and axanthic phenotypes. Pygmy rattlesnakes (Sistrurus miliarius miliarius, S. m. barbouri, S. m. streckeri) range from the southeastern U.S. to eastern Texas, with overlapping species that intergrade. They inhabit various environments such as pinewoods, hardwoods, palmetto areas, marshes, wet prairies, pine flatwoods, and dry river bottoms. They are often found among logs, rocks, woodpiles, junk piles, and open grass where prey is abundant. Pygmy rattlesnakes exhibit a wide range of coloration; some populations feature orange to red hues, while others are dark, nearly black or patternless. The eastern massasauga (S. catenatus catenatus) was recently proposed to be listed as threatened by the U.S. Fish and Wildlife Service. It is a small, thick-bodied rattlesnake inhabiting shallow wetlands in parts of Illinois, Indiana, Iowa, Michigan, Minnesota, New York, Ohio, Pennsylvania, Wisconsin, and Ontario, Canada (one of only three rattlesnake species in Canada). It displays a dorsal pattern of black or dark brown oval-shaped blotches on a gray or reddish-brown background. Major factors contributing to the eastern massasauga’s population decline include habitat destruction, farming, weather pattern changes, and recent documentation of snake fungal disease in some populations. In the northeastern U.S., there has been one documented case of hybridization with a timber rattlesnake, creating a hybrid intergrade. The sidewinder (C. cerastes) is a small desert rattlesnake species that thrives in the hot, sandy, barren deserts of the American southwest.Sidewinders possess the ability to move forward just like any snake; however, they are well-known for crawling sideways for long periods while traversing massive sand dunes.
The evolution of sidewinding locomotion in snakes is an adaptation to handle hot surface temperatures. This movement prevents heat absorption because highly coordinated actions elevate all but two small body sections above the surface at any time, minimizing heat intake from the earth. Characteristic J-shaped marks follow a diagonal course during this locomotion, making sidewinder tracking on dunes quite easy. Sidewinders have two distinct physical traits: a spinal ridge along their spine and a modified supraocular scale resembling a horn over each eye. They can often be found partially buried after using cratering, a technique where the snake flattens its body while coiled in sand to hide and ambush prey. Like most rattlesnakes, sidewinders are ambush predators that typically consume lizards and small rodents. Banded Rock Rattlesnake The banded rock rattlesnake (C. lepidus klauberi) is one of the smaller rattlesnakes in the U.S., rarely exceeding 2 feet in length. With a spotty distribution in the American southwest, it inhabits mountain ranges along the Mexican border in Texas, New Mexico, and Arizona, and has a wider distribution in Mexican mountains. Banded rock rattlesnakes are cryptic due to their coloration, small size, and speed, and are not commonly observed. They typically live at elevations of 5,000 to 8,000 feet in open rockslides, rocky outcrops, and rocky areas within pine-oak and conifer forests. Ridge-Nosed Rattlesnakes The Arizona (C. willardi willardi) and New Mexico (C. w. obscurus) ridge-nosed rattlesnakes are extremely similar, differing mainly in dorsal patterning and distribution. Both have a raised rostrum forming a distinct upturned ridge, which gives them their common name. The Arizona form is reddish-brown with small, randomly distributed dark scaling and a pattern of broken, light-colored crossbars bordered by dark brown to black scales. The New Mexico ridge-nosed rattlesnake is pale gray to tan with poorly defined darker crossbars, a patternless head, and lacks the dominant facial stripes of the Arizona form. The entire U.S.The Twin-Spotted Rattlesnake (C. pricei pricei) is the smallest rattlesnake in the U.S., often appearing in poor condition in the wild, with the largest specimen recorded at only 26 inches long. Its range includes the Chiricahua, Huachuca, Santa Rita, and Pinaleno mountains of southeast Arizona, where it inhabits rock slides and hardwood or conifer forests at elevations above 6,000 feet. There are scant reports of human envenomations, and no fatalities are known.
Populations of Willardi can be found in canyons near the Huachuca, Santa Rita, Patagonia, and Whetstone mountains in Arizona, while Obscurus distribution in New Mexico is limited to the Peloncillo and Animas mountains. Both snakes survive at high altitudes in rocky areas of pine-oak and conifer woodlands, with few envenomations reported and low venom toxicity. Safety Tips for Keepers: Only experienced keepers should maintain rattlesnakes, minimizing direct contact and using proper tools. Determine the venom type, as it varies by species; for example, Mojave rattlesnakes have neurotoxic venom, while sidewinders and speckled rattlesnakes may have hemotoxic or myotoxic venom. Gain experience through zoological institutions or mentorship, as rattlesnakes are unpredictable. Training helps anticipate movements and strikes. Interact minimally during feeding and cleaning, using hooks and tongs with two people present. Open cages only with tools, and move snakes into secure containers like trashcans or buckets with lids. Shift boxes can prevent interaction but are harder to use with pit vipers like rattlesnakes compared to elapids.These methods to remove animals from their enclosures will allow keepers to clean the enclosures. To assist in feeding, long hemostats or tongs can be used to place and remove food items within cages.
Keeping rattlesnakes is a potentially life-threatening decision. Any time the door to an enclosure containing a rattlesnake is opened, you are at risk of being bitten. Rattlesnake Envenomation People are bitten trying to kill, catch or handle rattlesnakes, and approximately 7,000 to 8,000 snake envenomations occur within the United States and Canada annually, with a large percentage caused by rattlesnakes. Medical attention should be sought immediately if envenomation is suspected. Any rattlesnake bite could be life threatening, and the person who has been bitten should be transported to a hospital by paramedics to establish initial therapeutics. Delaying the pursuit of treatment for a rattlesnake envenomation is irresponsible. No one should ever hesitate to seek medical attention for a rattlesnake envenomation, even if the person bitten is keeping rattlesnakes illegally (though doing so is not recommended, of course). Your life is more important than worrying whether or not your animals get confiscated. The first steps for successful first aid of a rattlesnake bite is getting to the nearest emergency facility; removing anything that could cause constriction on the body, such as rings, watches and other items; and keeping the bitten appendage below the plane of the heart. Many myths exist regarding the treatment of venomous snake bites. Immediate treatment options that should not be performed include tourniquet application, sucking out venom by mouth, or cutting the envenomation site first and then sucking the venom. Venom extractors are of little use and not recommended, either. Envenomation severity depends on several factors, including time elapsed prior to treatment, the snake species, venom properties and quantity of venom injected, number of times bitten, the victim’s age, size, physical condition and response to venom. Fang penetration is not necessary for envenomation—any break in a person’s skin through which venom penetrates can cause clinical signs of envenomation. Keep it Legal Venomous laws vary between states. Prior to keeping any rattlesnakes, please contact your local government organization that regulates wildlife (e.g., the California Department of Fish and Wildlife, Florida Fish and Wildlife, etc.) to determine first if it’s legal, and if so, to learn the proper avenues necessary for you to become a legal keeper of rattlesnakes. It is your responsibility as a keeper to obtain and possess these beautiful animals within the guidelines of the law. Doing so illegally only provides more justification for organizations such as People for the Ethical Treatment of Animals (PETA) and the Humane Society of the United States (HSUS) to try and restrict our rights to keep these amazing species. Sean M. PERRY, DVM, is a veterinarian working at the University of Illinois College of Veterinary Medicine, with a special interest in reptile medicine and surgery.His research interests include evaluating artificial reproductive technologies in reptile species.
Additionally, he is dedicated to advancing emergency and critical care medicine in reptiles.