Snake! Just say the word and for a lot of people, shivers go up and down their spine. Snakes have been objects of fascination or fear and suspicion since ancient times. Sadly, for some people, their first reaction to a snake is to pick up the nearest shovel or hoe and quickly dispatch the intruder. Snakes, however, play a key role in the balance of nature.
We often are asked: What kind of snake is it? Is this snake poisonous? What good are snakes anyway?
The following information is an attempt to answer some of the most commonly-asked questions about these fascinating, yet all too often persecuted, maligned, and misunderstood creatures.
- Snakes look so different, Where do they fit in with the other animals?
- Texas is always bragging about having the most, the biggest, and the best of everything. How do we rank in terms of snakes?
- Which of the five families of snakes that occur in the U.S., are found in Texas?
- What basic information should people know about snakes?
- Where do snakes occur in the world?
- What makes snakes look so different?
- What other distinctive characteristics do snakes exhibit?
- How did snakes get to look the way they do?
- How can you tell one snake from another? Don't they all look alike?
- What other ways can you identify a snake, if the color pattern doesn't give it away, and the snake is acting too feisty for an analysis of the scale patterns?
- How would you describe the behavior of most snakes?
- What does it mean to be cold-blooded?
- Do snakes have any social structure? Do they ever hang out in packs?
- How long do snakes live?
- What do snakes eat? How do they swallow their food?
- Family life - Reproduction - Courtship - Finding mates
- Do snakes have any enemies?
- How do snakes defend themselves?
- Is a snake "poisonous" or "venonmous?"
- How can I tell the difference between a venomous snake and a harmless one?
- How best can I avoid getting bitten by a venomous snake?
- How can I make my habitat hospitable to snakes?
- How can I discourage snakes from coming into the yard?
- Are there any snakes considered rare, threatened or endangered in Texas?
- Fun Facts about Snakes
- Are there any good books on snakes?
Like us, snakes are vertebrates, which means they have a backbone consisting of numerous vertebrae that provide their bodies with flexible support. They share this characteristic with fishes, amphibians, other reptiles, and mammals. Snakes belong to the Class Reptilia, meaning they are cold-blooded, have skin covered with scales and lay eggs (oviparous). Some snakes retain the eggs within their body until they hatch, thereby giving birth to live young (ovoviviparous). Snakes are close cousins to lizards and share the spotlight with them in the reptilian Order Squamata. Snakes belong to their suborder Serpentes, consisting of 15 families, 417 genera and over 2,375 species worldwide. Five of these families (depending on your classification system) are represented in the United States by 50 genera and 127 species. Snakes, though of relatively recent origin, are a diverse and highly successful group.
Texas is always bragging about having the most, the biggest, and the best of everything. How do we rank in terms of snakes?
Granted some Texans may be reluctant to brag about this one, but the Lone Star State is, undeniably, a cornucopia of snake diversity. Although the exact number of species is hard to determine, we boast a stunning 76 species of snakes. If you include both species and subspecies in that number, it gives you a grand total of 115 or more - the highest number in all of the United States. The vast majority of Texas' snakes are non-venomous and completely harmless. Only 15% of the total number are venomous and should be treated with caution and respect. The venomous varieties can be grouped into four basic categories: coral snakes, copperheads, cottonmouths (also known as water moccasins), and rattlesnakes.
Texas hosts four of the five US families of snakes: the Slender blind snakes (Leptotyphlopidae), the Advanced snakes (Colubridae), the largest group; the Old World fixed front fang snakes (Elapidae) and, finally, the New World Pit vipers, the hinge-fanged snakes, a subgroup of the Viper Family (Viperidae). Texas can claim no boas (Boidae).
Snakes occur throughout the state of Texas. Of the 254 counties in Texas not one of them is snake free. According to Fred Gelbach of Baylor University, 36% of the 68 snake species in Texas are of eastern origin, like the Eastern hognose snake and the Texas rat snake. Twenty-three percent are basically western or southwestern in origin, like the long-nose snake, ground snake and prairie rattlesnake. Fourteen percent are central US Great Plains species, like the Texas blind snake and the central lined snake; while nine percent hail from the Chihuahuan desert region, including the Trans-Pecos rat snake and the rock rattlesnake. Another nine percent are transcontinental species and occur throughout the US, like the speckled king snake and several species of garter snakes. Finally, a few snakes, like the beautiful indigo snake, cat-eyed snake and black-striped snake are essentially tropical species reaching the northern limits of their range in the Tamaulipan region of south Texas. There is a single endemic species snake, the Harter's water snake, which consists of two subspecies, found only within the state of Texas. The Central Texas region has the largest number of species. As for parts of Texas where there are many individuals, West Texas, Central Texas and South Texas are great places to go to find snakes.
Snakes are a natural and integral component of the ecosystem. As predators, they are invaluable for their role in maintaining the balance of nature by helping to keep populations of their prey in check. Their prey consists of everything from earthworms to rabbits, and this includes other snakes. Snakes are especially important in the control of rodents. Bull snakes can be a farmer's best friend.
Snakes are distinctive in possessing an elongated, scaly body without limbs, external ear openings or eyelids, and like all other reptiles, they are cold-blooded or, more properly, ectothermic. Snakes cannot tolerate extreme cold and will normally hibernate in the winter, emerging from their dens late February or early March in Texas. They also avoid extremely torrid conditions, confining their activity in hot climates to early morning, evenings, and night-time. Limblessness has in no way been a handicap to evolutionary success. Snakes successfully occupy many terrestrial, arboreal, underground, and aquatic environments around the world.
As a group, snakes are cosmopolitan, occurring on all major land masses except Antarctica, Iceland, Ireland, Newfoundland and New Zealand. While there may be more species of lizards in the world, snakes are less limited in distribution, so that in most areas there are more snakes than lizards. Among the reptiles, snakes are the most successful group.
All snakes have long, flexible, scaly bodies. But underneath their scaly skin, they possess muscles, bones, lungs, intestines, a heart and a liver, just like other vertebrates. To accommodate the long slender body, most snakes have many more vertebrae and ribs than do other vertebrates of comparable size. Additionally, most or their paired internal organs have been reduced , removed, or drastically repositioned to get a better fit. A snake's jaws are truly unique, allowing the animal to swallow prey much larger than the narrow mouth opening would deem possible. A snake can do this because the two halves of the lower jaw are joined by a stretchable ligament. The expandable gape enables the snake to engulf a large prey item rather like a stretchable stocking. Other structural features facilitate the process including the loose articulation and reduced number of the bones supporting the jaws, a protrusible glottis that permits breathing while the mouth is blocked by prey; and sharp, back-pointing teeth which help manipulate and drive the victim irrevocably backward towards the stomach.
Snakes possess a few other typical traits. The forelimbs and pectoral girdle are totally absent in snakes, though vestiges of the hind limbs and pelvic girdle do still occur in primitive snakes. Eyelids don't move giving snakes that riveting, stony-eyed stare, while the cornea is protected by a fixed transparent scale called the brille. This transparent scale is shed along with the rest of a completely molted skin. And while snakes have no external ear and thus cannot hear air-borne sounds, they are very sensitive to vibrations emanating from the ground. The tongue is long, retractile and fork-tipped. Though it appears menacing, it is not a stinger, inflicts no wound, and contains no poison. This sensitive mouth part tells the snake much about its surroundings. It can be flicked in and out vigorously then inserted into two depressions on the roof of the snake's mouth called the "vomeronasal" or "Jacobson's" organ. These function together as a highly sensitive chemoreceptor system enabling the snake to "taste" and "smell" the particles of the air. Some snakes, like the pit vipers, can even sense heat and target the position of a warm-blooded animal in the vicinity by means of heat sensor pits. These may be located along the lips or between the eye and the nose of the snake depending on the species.
Snakes are the most successful of all living reptiles. They are amazingly adapted for their life close to the surface of the ground. And while many people assume that snakes have always looked the way they do, scientists believe that this most recently evolved of all the reptile groups achieved their current form as slender, tubular animals devoid of legs, quite late in geological history, some 65 million years ago. They are believed to have evolved from a Mesozoic monitor-lizard-type ancestor. According to Alan Tennant, who wrote The Snakes of Texas, the scenario goes something like this. In order to escape increasingly heavy predation from the many agile, voracious, warm-blooded little dinosaurs which combed the late Cretaceous plains in search of easy, slow-moving prey, ancestral snakes took to the underground. Over time, in the safety of subterranean burrows, their lifestyle changed radically as they gradually abandoned their limbs, free breathing, good eyesight and hearing - a big sacrifice for any animal - to better suit their new way of life. Foregoing life on the surface, they came to rely more on taste and smell than on sight or a keen sense of hearing for their survival and legs were more a hindrance down under than a help. Bit by bit, they were no longer lizards at all. Other herpetologists contend that the evolutionary history of snakes is shrouded in mystery. And while they concede that snakes are morphologically distinct and easily distinguished from lizards, they believe that snakes are still basically highly modified lizards.
While it's true that snakes are all basically shaped like a rope, there are several discernible differences within this basic format. Despite being superficially similar, upon closer inspection, snakes display an incredible diversity of color, scale pattern, and subtly of form. For instance, some snakes are small and slender, more like large eyeless earthworms than snakes. Take the Texas blind snake, for example. Others, much larger, seem long and whip-like. The western coachwhip and the buttermilk racer fall nicely into this category. Still others can be thick and stocky. Western cottonmouths are definitely chunky. It's always instructive to notice the relative width of the head in relation to the body as well as the relative length of the tail. The length and shape of the snout anterior to the eyes can also be a give away. The hognose, patchnose and longnose snake are good examples. While tails are usually somewhat longer in males than in females of the same species, relative length and thickness of the tail can also help to identify one species form another. Scale patterns are also extremely good aids to identification. Their number and distribution on various parts of the body are relied upon heavily in dichotomous keys to identify a specimen to species. And the scales themselves can be distinctive. Some are smooth while others are keeled. (The keel is a horizontal line-like ridge on the scale.) Smooth scaled snakes appear polished or satiny when the snake is seen up close, while roughly keeled snakes seem dull or sometimes, just after shedding, kind of velvety. Colors and color patterns are probably the first thin a person notices. Patterns can be roughly classified as striped or banded lengthwise, as in lined or garter snakes; or transversely banded, as in broad-banded water snakes. Some bands go all the way around the snake as in the coral snake, while others seem to only partially encircle the animal as in the gray-banded kingsnake. Some snakes have blotched patterns or have a row of large saddles along the back as in some rat snakes or copperheads. Other snakes possess small, elegant spots arranged in a checkerboard fashion as in the Buttermilk racer. Spots can also be uniformly distributed as in the Central American speckled racer and speckled kingsnake or they can be irregularly scattered as in the beautiful desert kingsnakes. A few snakes like the diamondback rattlers have a symmetric series of rhombs or diamonds along the back. Indigo snakes, on the other hand, are a uniform dark color. Snakes can be all green, brown, blue, black, peachy coral, or gold. Some snakes even have melanistic or dark morphs, while all grades of albinos also exist. It's always good to check the color of the belly which is sometimes a lighter or different color or has a distinctive pattern compared to the rest of the body. Remember the young of some snakes are sometimes quite different in color and pattern from adults, which can be confusing. Let your portable field guide to the snakes be your constant companion in the field. There are a number of good ones available at your local library or at bookstores. Some of the best titles for Texas are listed at the end of this document. The more species of snakes you observe and identify, the more you will come to appreciate the beauty and complexity of coloration and pattern design. For many herpetologists (people who study reptiles), snakes embody incomparable works of art.
What other ways can you identify a snake, if the color pattern doesn't give it away, and the snake is acting too feisty for an analysis of the scale patterns?
Many snakes give their identity away by their characteristic and sometimes bizarre behavior. An excellent example of this is that of the super thespian, the Texas hognose snake, who can really put on a show. This amazing critter has evolved an elaborate pattern of behavior designed to make it as unappealing as possible to any potential predator. If molested, according to Alan Tennant, it may coil or raise its head, and flatten its forebody to make you think it's bigger than it really is. If you are still unimpressed, the snake will next launch several pseudo strikes in your direction, violently jerking its head backward each time. This should immediately suggest to you the aggressive style of pit vipers and frighten you off. If not, next the intrepid snake will emit a sharp, hair-raising hiss with each breath it takes. If the observer continues to be unmoved by all this, the snake will proceed to act two of the performance. It now resolutely conceals its head under its tightly spiraled tail and begins to writhe convulsively, regurgitating and at the same time discharging a foul-smelling musk form its anal glands. Still not convinced? The final ploy - the piece de theatre so to speak - the snake turns belly up with its tongue hanging loosely and pathetically from its open jaw - to all appearances dead as a door nail. Should you take a stick and try to turn it upright - bingo it will flop back over again. Just to let you know in no uncertain terms, there is no such thing as a dead snake in an upright position. In evolutionary terms, this amazing repertoire of behavior must have worked more times than not, or these snakes wouldn't still be around doing this. Not all snakes exhibit such amazing antics, but many of them do have characteristic behaviors that will give you immediate clues to their proper identity.
Generally snakes are shy and retiring. And when you think about it, they really live rather sedentary lives. Most are non-migratory and if they do migrate, they don't go long distances. Much of their behavior is a function of survival within the limits and opportunities of ectothermy or "cold-bloodedness."
Like all living reptiles, snakes are cold-blooded or, more appropriately, ectothermic. This does not mean that their blood is always cold, but that their body temperature varies with that of the external environment. Unlike war-blooded birds and mammals, snakes are unable to regulate the temperature of the body internally. Snakes can, however, absorb heat form the ground, form the surrounding air, and from objects next to them. They can also create certain amounts of heat by flexing their muscles. This makes their life style different, but not necessarily inferior to that of birds and mammals. In fact, snakes have been able to colonize and adapt to many environments which have proved hostile to warm-blooded animals. Being ectothermic demands less energy. High levels of metabolism don't need to be maintained. So snakes aren't forced to eat all the time. Growth does not have to be constant, rather it can be discontinuous with long pauses between spurts. There can be long periods of fast between meal-times, sometimes as long as three years. Cold-bloodedness is the original or ancestral state of life (all invertebrates, fish, amphibians and reptiles are ectothermic), it is not an inferior state, just different, with different limitations and possibilities. Being ectothermic makes snakes sensitive to both very cold and very hot temperatures. They have a narrower range of temperatures, only about 30 degrees, within which they can survive. Snakes need to hibernate when the ground freezes and air temperatures descend below 32 degrees for extended periods of time. Likewise, they need to take shelter during times of excessive heat. Temperatures over 110 degrees for prolonged periods can be lethal. Snakes protect themselves from temperature extremes by means of behavioral modifications rather than by internal thermoregulatory devices. To warm itself, a snake can bask in the sun, or lie on a paved road at night. To protect itself from cold temperatures, it can burrow deep below the ground where the soils are warmer and unfrozen.
Snakes are absolutely dependent on external heating for their muscular activity and the important life processes of digestion and gestation. They cannot derive their body heat chemically from their own metabolism. So they can live only in parts of the world where the daily and seasonal temperatures are fairly equable. Snakes are just as sensitive to overly hot weather as they are to excessively cold temperatures. Survival time under extreme conditions can be as short as ten to twelve minutes. Even sidewinder rattlesnakes may succumb to the heat at about 113 degrees depending on the duration of exposure. Under cold temperatures, a snake becomes increasingly lethargic. Instinctively it will seek some refuge. It must do this before it becomes immobilized by the cold. In paralyzing cold, snakes can no longer procure food or defend themselves against enemies. In short they can no longer move. The can endure temperatures of 37 degrees for a few days, but not extremes in the teens. Temperatures between 80 and 90 degrees are probably the best and most comfortable for them. Snakes will behaviorally adapt to the temperature ranges of an area. In habitats where daytime temperatures are lethally hot, they will confine their activities to the night. In an area with excessively cold winter temperatures, a sudden drop in temperature will induce long periods of wintertime hibernation with activities resumed in the spring with the return of warm temperatures. Many snakes mate and resume foraging activities in the spring. Snakes can cool themselves by seeking shade, lying in shallow pools of water or crawling down a rock crevice out of the sun. They can warm themselves at night in hot climates by lying on still warm paved highways.
Snakes are essentially solitary and don't congregate into large organized groups. Certain favorable environmental conditions such as the burrows of other animals, attractive shelters for hibernation, or termite galleries may attract small groups of individuals. There is, however, no community like or social structure within these groups. This lack of social organization may make it difficult for snakes to find members of the opposite sex during mating season. Males search out females by smell. Females may, however, congregate at egg-laying areas that are especially suitable.
Snakes are comparatively long-lived. Even small snakes may live as long as 12 years. Large species may live to a ripe old age of 40 years or even longer.
There are no snake vegetarians. Snakes are confirmed meat-eaters. Depending on the species, prey items consist of slugs, worms, insects of all kinds, crustaceans, fish, amphibians, other reptiles, birds and/or mammals. Eggs are also a favorite menu item for some species. Prey is generally swallowed whole. It is usually take alive. Thorn-like teeth which are curved backward help move the prey item in the direction of the stomach. The prey is often seized in the mouth by a rapid strike, and the process of overpowering and swallowing begins. If the snake is nonvenomous, the prey is usually small in size relative to the snake. A few species can subdue larger more active prey by constriction, thus immobilizing the victim before swallowing it. Poisonous snakes are able to subdue large active prey items by striking them, envenomating them with a complex proteinaceous substance which both begins the digestion process and kills the victim at the same time. Many venomous snakes will immediately release their prey, allowing time for the poison to do its work, and locate them later by means of the heat-sensing pits, sight or scent. Once relocated, they proceed to swallow the moribund carcass. Teeth are frequently broken off in the process of the strike, but they are soon replaced with new ones ready for use.
Most snakes have restricted food preferences, while others are more eclectic in their tastes and will take anything that they can effectively subdue and engulf. A number of snakes specialize in taking certain kinds of prey only and have special adaptations to do this. Slender blindsnakes specialize in eating ants and termites. Hognose snakes are toad specialists. The crayfish snake, as its name implies, targets crayfish or similar crustaceans. Some snakes are fish-eaters, others are bird egg specialists. Kingsnakes and Indigo snakes are snake specialists, Smooth and Rough green snakes are insect-eaters with a special liking for crickets, grasshoppers and caterpillars. Rat snakes, great friends of the farmer, of course, love to eat mice, voles, cotton rats and the like.
In temperate climates, mating usually takes place in the spring. Commonly a snake will have spent the winter in the company of others of its kind in a large hibernation burrow. Snakes emerge en masse from their dens at this time and can be found basking in the sun, sometimes in significant numbers. The first order of business, aside from eating, is for the snakes to shed their skin. This molting activity releases a chemical signal in those female snakes that already have mature eggs in their oviducts triggering a readiness to mate. Males probably locate females by scent which arises from epidermal secretions emanating from just inside the female's cloaca. Certain female snakes mate with only one partner in a season while other females store viable sperm from several males for various lengths of time, sometimes up to five years. Courtship usually consists of pushing, rubbing and weaving movements initiated by the male. He will rub his chin against the female's neck thereby stimulating her to receptivity. In some cases there may be a nuptial interlude where the snakes coil around each other. Males of some species participate in what is described as a ritual display of aggression called a combat dance. It is not known whether this is territorial or a display to females in the vicinity. It is only done during mating season and it occurs only between males. Fertilization is internal and the male will terminate courtship activities by getting into position with relation to the female and inserting one side of the double pronged intromittent organ called a hemepene. Sperm passes along a groove in the hemipenis and enters the cloaca then travels up the oviduct where it fertilizes the waiting eggs. Females of some species appear to guard their eggs, but this is not commonly observed in most species. Young rarely if ever receive any kind of protective care form the female. Most snakes simply lay their eggs on the ground usually in warm damp soil. May lay eggs in or under rotting logs, under bark of downed trees, under stones, in holes in the ground or other secluded spots. Snakes can lay as few as 1 to as many as 100 eggs. A number of snake species bear live young. Few snakes exhibit any kind of parental care.
Snakes and people have the same arch-enemy: people. Humans have always waged war on snakes and there is no way of knowing just how many millions of harmless individuals have been battered, shoveled, run over, gassed, and shot to death through the years. And while it's understandable that people object to the dangerously venomous snakes, it is a shame to kill all the harmless ones too, giving as a rule of thumb - the only good snake is a dead snake. For many of us, any enemy of a snake is a friend of ours, no matter what form it may take. In the natural environment, several animals stand out as enemies of snakes. Badgers are major snake predators so are weasels. Several species of wild cats including mountain lions, bobcats, ocelots and jaguarundis will take snakes. The domestic and feral cat should be included in this group. Domestic cats will often take the smaller snakes, both harmless and venomous. Other snakes and large lizards are known to prey on snakes. The indigo snake and the kingsnake are well-known snake predators. Kingsnakes appear to be highly resistant to the venom of most venomous species and over power their victims by constriction. As a matter of fact, a kingsnake will eat almost any snake they find that is small enough to be eaten whether it is venomous or not. When you think of it, the elongate body of a snake is a very convenient shape for consumption by another snake - no pesky legs or horns to get in the way. Some people in South Texas and Mexico used to keep indigo snakes as pets around the house to keep other snakes away. Some birds are well known snake predators. They may eat them as part of a diet which includes other groups of animals or they may be specialists. In the United States, perhaps the best known avian snake predator is the Greater roadrunner. They probably eat more lizard than snakes but that has not prevented quite an elaborate folklore to grow up about their snake hunting prowess. Some roadrunners were reputed to build a wall of cactus spines around the rattlesnake victim so that it would die of heat prostration. Smart bird, probably fiction. Laughing falcons in Mexico are snake specialists and focus most of their foraging attention on the capture of snakes. Turkeys, many large buteo hawks, eagles, herons and cranes are also known to devour snakes with relish when they are small enough to capture. As for domestic animals, pigs like to eat snakes and will attack them viciously before devouring them. They also appear to have a high resistance to snakes venom due to the slow transfer through all that fat. But finally all of the above are no match for man. Through direct actions or indirectly we have completely eradicated snakes in some localities. We have destroyed or modified their habitat and their food supply. We have wiped out great numbers of individuals due to fear, anger, sadism, greed, fun, desire for their hides, or to a lesser extent, for food. Of course, snakes are not our only victims, other animals suffer too. But because of widespread human aversion, snakes have been singled out and targeted as bad animals and have been persecuted beyond all reason.
Think about it, suppose you had neither arms nor legs and were shaped like a flexible hose, with top speeds not exceeding 3 mph. Add to that, being cold blooded and always at the mercy of the weather, especially the temperature, how would you defend yourself? Amazingly snakes have evolved a number of ingenious behaviors and clever strategies to stay alive in an often hostile environment filled with hungry, aggressive, warm-blooded predators with highly developed senses. Snakes are like magicians, and many of them sport a versatile bag of tricks. Most snakes have adopted a somewhat cowardly or cautious attitude towards danger. Defensive tactics include staying hidden and relying on their excellent camouflage in hopes that the predator won't notice that they are even there. I suspect that this is one of their most successful ploys. Some snakes will curl up into a tight ball with their vulnerable head tucked safely and inconspicuously away somewhere in the middle of their body. Other snakes will play dead or try to "bluff" the potential predator into thinking they are larger and more dangerous than they really are. A very common and consistently resorted to strategy is to leave the scene of danger as quickly and unobtrusively as possible, avoiding confrontation at all costs. Discretion is the better part of valor. Finally a few snakes have evolved the ability and the arsenal of equipment necessary to stand their ground and defend themselves against enemies much larger than themselves. If cornered and not given an opportunity for retreat, they will strike with speed and force and envenomate their enemy.
An animal that has venom is called "venomous." An animal that would make you sick if you ate it is "poisonous." Only a small number of snakes have venom. So although some people refer to those snakes as "poisonous," technically, they mean venomous.
Unfortunately, there is no one simple hard and fast criterion a person can use to tell a venomous snake from a harmless one. None of the popular criteria such as a broad, triangular head, a heavy body, cat's eyes (vertical pupils), a flat body, or rough scales are safe since both harmless and dangerous snakes are known to share some or all of these traits. The only unfailing method is an examination of the snake hollow of grooved fangs and venom glands. For obvious reasons, this is not a practical approach. A better method is to know which venomous snakes occur in your area and have a good idea about what they look like. With this in mind, keep a copy of a good field guide to Texas snakes handy, and remember a few simple facts. While many species of harmless snakes will vibrate their tail, only rattlesnakes have rattles which produce a recognizable "cicada-like" buzz. And while most rattlers will sound their rattles when they sense your presence, this is not always the case. If you catch a rattlesnakes totally by surprise, ti may choose to strike first. Pit vipers, such as rattlesnakes, water moccasins, massasaugas, and copperheads, do have cat's eyes with vertical pupils, but so do Texas lyre snakes, Northern cat-eyed snakes and Black-lined snakes which are harmless. Knowing the range of these latter snakes and knowing where you are will make this a more valuable criterion. The Texas lyre snake occurs only in extreme West Texas while the Texas cat-eyed snake and the Black-lined snake occur in extreme South Texas.
Coral snakes, which are venomous, do not have cat-eye's. They are the only venomous snake in Texas that is brightly colored red, yellow, and black bands completely encircling the body. Because harmless Texas scarlet snakes and Louisiana and Mexican milk snakes share the red, black, yellow coloration pattern, it is important to notice the order of the colored bands. A good memory-jogging device to learn is "Red next to black is O.K. for Jack; red next to yellow will kill a fellow." Finally, with scarlet and milk snakes, the bands do not completely encircle the body but stop at ground level, under-bellies being uniform in color.
Many large harmless snakes appear to have large triangular heads which are wide in proportion to the neck, especially when you are looking down at them, so this is really not a good criterion in the field. Additionally, many harmless snakes can make themselves look and act like pit vipers, the Texas hognose snake is a good example. Water moccasins, also known as cottonmouths, do not have rattles, but the do have facial pits. Sometimes these are hard to see without binoculars and still maintain a safe distance. Blotched, Yellowbelly and Diamondback water snakes are often mistaken for water moccasins because they share thick trunks, dark, dimly patterned backs and sides, as well as the same aquatic habitat. Cottonmouths do exhibit rather distinctive behavior, however, that usually helps to differentiate them in the field. They are significantly less agile than water snakes and often hold their ground and gape open-mouthed in a threat posture. The open gape is cottony white, hence their common name.
Copperheads are venomous and can be prevalent in wooded suburban neighborhoods. While their venom is only about half as destructive as that of an equal quantity of western diamonback venom, they are sometimes hard to see in habitat. Due to their cryptic coloration, they blend in beautifully with their surroundings. While they are not highly aggressive, they often get stepped on. According to Alan Tennant in Texas Snakes, not a single death resulted from 308 copperhead bites over a 10-year period.
The best defense against venomous snakes is avoidance. To avoid a particular animal, it is best to know what it looks like and where it is likely to be found. Snakes are often found under rocks, fallen limbs and in the leaf litter. They can also be hidden in tall grassy & brushy areas. Rodents are one of a snakes favorite meals, so avoid areas where mice and rats may be, such as trash, brush and rock piles, stacked lumber and stone walls fences. When outdoors, always look where you step. When you know you are going to be in snake territory, wear boots, thick jeans or chaps and gloves. Never reach under rocks or into holes or other blind crevices. This is definitely asking for trouble. If your are playing ball or frisbee and it lands far from you in tall grass, LOOK before you reach down to pick it up. This also goes for hunters who are retrieving their downed game. Look before you reach. Don't remove or turn over stones and rocks with your bare hands. Be careful when climbing around rocks and watch where you sit. Always watch where you step on warm rocks, especially in spring. Basking on rocks is a popular activity among snakes as they warm themselves in the cool morning air. Be careful when stepping over or on fallen logs. Always pay attention to where you step and make sure you can see where you are placing your feet. The best rule of thumb is to watch where you put your hands and feet; don't put them in places without looking and don't put them in places where you can't see. If you lift a stone or log or any object under which a venomous snake might be, first move it with a stick or hook. Don't place your fingers under it. You can use your foot if you have thick leather boots. If you are walking in grass brush or cactus patches, stay in the cleared areas as much as possible. Remember rattlers are hard to see in their natural habitat as they are protectively colored. Avoid walking around your campsite in the darkness. Rattlers are nocturnal much of the year. If you have to move about, use a flashlight to light your way and don't go barefoot. Step on a log never over it. Carry a stick so that when you walk through tall grass and brush, you can beat the ground with the stick. This will warn the snake that you are in the area. Most snakes will try to escape from the vibrations. If you should see a snake remain still and slowly move away. Pit vipers strike at movement. When you just hear a rattlesnakes, but don't see it, don't move until you have ascertained which direction the sound is coming from. You don't want to mistakenly move towards instead of away from the snake.
In Texas we have an average of 2-3 deaths per year from snakebites, compared with 5 to 7 for insect bites and 8 for lightning. The closer the bite to the heart, the more dangerous it is. Children and the elderly are particularly vulnerable to the effects of snakebites. Because children are small and close to the ground, they are often bitten on the face and arms. Finally, the best approach to avoid getting bitten by a venomous snake is to learn to recognize the venomous snakes of your area. Avoid killing the harmless ones as these are competitors of the rattlers for food. If you take a trip away from your area, learn which venomous snakes occur there and what they look like. Finally, don't let the fear of venomous snakes ruin your enjoyment of the out-of-doors. Poisonous snake bites are rare occurences. Being careful, alert and knowledgeable is the best way to avoid any danger of being bitten.
For those landowners, farmers or ranchers (even homeowners) who like the idea of making their land hospitable to snakes, there are several things you can do to attract them. Snakes are attracted to loose rock piles, large brush piles, hollow dead logs where the leaf litter has been allowed to pile up a bit. A nice lake or large pond with good emergent vegetation can be a big attraction for water snakes and the more aquatic species. If your land hosts lots of meadow voles, deer mice, cotton rats and the myriad of other small rodents that abound in the country or on farms, rat and gopher snakes will find this very attractive.
Snakes often occur in the vicinity of suburban and urban residential areas. They can even show up occasionally in your backyard. If the presence of snakes is deemed undesirable, removing their shelter is one of the most effective ways of discouraging them. Eliminating rock piles, brush piles, and areas of tall grass will cause snakes to seek a more suitable habitat. Store lumber, wood piles and other debris around the home at least 18 inches off the ground. Controlling insect and rodent populations in the area will also help to discourage snakes by eliminating their food supply. Snakes will sometimes enter houses, barns and other buildings because they are attracted by the presence of rodents and insects as well as by the cool, damp, dark shelter provided by these buildings. To keep snakes out of houses or other buildings, you must seal off all entry points. Snakes usually enter a building at or below ground level. For this reason, all openings around water pipes, electrical outlets, doors and windows should be sealed. Any holes in masonry foundations around the home should also be sealed off with mortar. Hardware cloth or sheet metal can also be used to seal holes in wooden buildings or siding.
The following snakes are considered either threatened (T) or endangered (E) in Texas:
Northern scarlet snake (Cemophora coccinea copei) T, Texas scarlet snake (Cemophora coccinea lineri) T, Black-striped snake (Coniophanes imperialis) T, Indigo snake (Drymarchon corais) T, Speckled racer (Drymobius margaritiferus) E, Northern cat-eyed snake (Leptodeira septentrionalis septentrionalis) E, Brazos water snake (Nerodia harteri harteri) T, Concho water snake (Nerodia harteri paucimaculata) E, Louisiana pine snake (Pituophis melanoluecus ruthveni) E, Big Bend blackhead snake (Tantilla rubra) T, Texas lyre snake (Trimorphodon bisutatus vilkinsoni) T, and the Timber rattlesnake (Crotalus horridus) T.
- Snakes range farther north and occur at higher elevations than lizards. They also adapted to a much wider range of environmental conditions. There are no snakes in Ireland, Newfoundland, New Zealand or on numerous south sea archipelagos.
- In Australia, the majority of snakes are venomous, approximately 80%. You need to watch where you step down under.
- Rattlesnakes can't hear the sound of their own rattles.
- Large prey and their slow metabolism give snakes the advantage of not having to eat so often. Few eat more than once a week; many eat from 8 to 10 times a year. Some are capable of very long fasts.
- Numerous species of snakes occasionally or regularly eat snakes of other species, usually much smaller than themselves.
For those readers interested in delving further into the subject of snakes, the following books, used as references for this document, are excellent sources of additional information.
Behler, J.L. and F.W. King. 1079. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: A.A. Knopf.
Burton, J.A. 1991. The book of snakes. New York: Crescent Books.
Collins, J.T. 1993. Amphibians and Reptiles in Kansas. Lawrence: University of Kansas Museum of Natural History.
Collins, J.T. and S. Collins. 1993. Amphibians and Reptiles of Cheyenne Bottoms. Hillsboro, KS: Hearth Publishing.
Smith, H.M. and E.D. Brodie, Jr. 1982. A Guide to Field Identification: Reptiles of North America. New York: Golden Press.
Tennant, Alan, with John E. Werler and Bill Marvel. 1985. A Field Guide to Texas Snakes. Houston, TX: Gulf Publishing.