There are many different species of animals roaming the earth these days. Some live on land and some live in bodies of water such a oceans or seas. They all look different and behave in different and unusual ways. Some use legs to move and other use fins however there are also species which nature didn’t give the gift of these body parts. These animals are called snakes and today we will be looking at these extraordinary animals, especially the ones located near our homes right here in North America.
Snakes belong to a group of animals known as reptiles. They are classified among other creatures such as lizards, turtles, and crocodilians. The ancestors of our modern snakes and lizards appeared along with the first dinosaurs during the late Triassic period, almost 200 million years ago. Fossils of those animals are rare however because of their soft and fragile bones which decomposed after they died.
All snakes have a backbone but lack limbs, eyelids and external ear openings. In addition, snakes have specialized row of scales along the underside of their bodies, whereas other reptiles have numerous rows. Finally snakes have unique skulls. The bones of their upper jaws are not united at the snout but are free to move away from one another, allowing the passage of larger prey items then would be otherwise possible. The snakes are the only known animal that can do that.
Snakes have many enemies and they have several means of preventing themselves from being killed or eaten. The most effective and common method is to avoid detection. Many are well camouflaged so that they blend into their natural surroundings. Others have very intricate markings consisting of blotches, bands, or stripes and are intended to confuse predators by disguising the outline of the snake. Yet other species are brightly colored. When the snake moves and the bands flicker quickly past, the predator may be confused as to which direction the snake is traveling. If a snake fails to avoid detection, or ir its warning colors don’t scare the predator away it may resort to other means of defense. Almost all the snakes bite event though only few are venomous. A few however play dead by turning over onto their backs and sticking their tongue out. This is usually accompanied by a foul small that is given off from their glands at the base of their tails.
Snakes have some of the same senses that other animals use, but they have also evolved additional senses because their eyesight and hearing are not very good. Snakes use their tongues to pick up scent particles from the atmosphere. First they flick their tongue and put it back into their mouths. The tongue is inserted into a chamber in the top of the mouth which is connected directly to the brain. Three groups of snakes, the boas, pythons and vipers have an additional sense organ not seen in other animals. These are the heat pits which are found on the face. Each pit is large and is lined with a sensitive membrane that detects the heat. In this way species with pits can pinpoint the position of warm blooded animals which form their main pray.
One of the most advanced snakes are the vipers. They are found throughout the world. Their most distinctive characteristic is a pair of shortened maxillae to each of which is attached a single long fang. Each maxilla is hinged so that the fangs can be folded back when not in use. The fangs have an enclosed canal through which venom is forced. Vipers are typically short and stocky with broad heads. The scales are usually heavily packed and the head is covered with small irregular scales. They are mainly a land species but some are semi aquatic. Vipers are well camouflaged snakes that ambush their prey, which consists of warm blooded vertebrates. Most species give birth to live babies but some do lay eggs. The viper family is divided into four subfamilies. The viperine and the Crotalinae have many species whereas the Azemiopine and Causine have few. The Crotaline are unique among snakes in possessing a pair of large heat sensitive pits between the eye and the nostril. One of the most common vipers found in North America is the Copperhead. It is found in all of Southeast and Southwest. These vipers love to live in rocky hillsides, swamps and desert oases. They usually feed on small birds and frogs. The copperhead has a triangular head and the scales are pink alternating with bands of dark red or chestnut brown. The tip of the tail may be yellow especially in young snakes. What makes these snakes most dangerous is the fact that they can easily be confused with the harmless water snakes that are usually kept in captivity. The copperhead is a venomous snake but usually people can survive the bite. Another common viper in the US is the Eyelash viper. This snake averages 80 cm in length and usually can be found in Mexico. This viper is also unique because of the cluster of small spine like scales over each eye. This snake comes in various colors.
Another well known snake is the rattlesnake. This is the most widely known venomous snake in North America. They are a very interesting group of snakes ranging from the large dangerous Eastern Diamondback and Western Diamondback to the small Mottled Rock rattler. These snakes are almost exclusively found in the US and are one of the most highly developed group of snakes. It’s very easy to recognize these snakes because of the rattle. Unfortunately these snakes are also the most preyed on by humans. The Eastern Diamondback in particular seems to be in a serious state of decline. These snakes only breed every other year in the wild and cannot sustain their numbers when mass amounts of them are removed and butchered each year. The rattle on the tail of rattlesnakes is formed from the successive remains of the scale covering the extreme tip of the tail. In most snakes this scale is comical and the end comes away with the rest of the shed skin. In rattlesnakes however the terminal scale is shaped like an hour glass with a constriction somewhere around its center line. After the first shed the skin around the terminal scale becomes thicker than normal. When the young snake sheds for the second time this scale is torn away form the old skin because is held in place by the constriction. Now a new skin is formed around the tip of the tail but it shrinks away from the piece of old skin so that it is attached only loosely. When the snake sheds again, the second layer is prevented form coming away. The tail has two segments one inside the other and the cycle starts again. Eventually a number of segments are built up, the oldest towards the end of the tail and the freshest towards its base. Each segment them represents a shed skin. However it’s rare to see rattlesnakes with more that six or seven segments because they are brittle and tend to fall off. During the winter rattlesnakes live in dens to keep warm. They are usually loners and don’t get along well, however during the winter there can be hundreds of rattlesnakes is a single den. This is one of few times they will tolerate each other. During the winter rattlesnakes usually hibernate and they can do that up tho sis months.
One of the most common rattlesnakes is the Western Diamondback rattlesnake. It is six to eight feet long and is one of the most dangerous snakes in the world. His distinctive diamond pattern running down his body servers him as camouflage. When threatened or startled the snake coils and vibrates the rattle at the tip o its tail emitting a loud rhythmic buzz. The sign of and impending strike. The snake may also raise its neck into an “S” curve. Even when coiled diamondbacks can strike a distance equal to half their body length. Diamondbacks feed primarily on frogs, rodents, rabbits, lizards, and birds, all of which it can swallow whole. They can be found in desert, grassland, woodland and river bottom habitats. They live about fifteen years and spend most of their time relaxing in the shade. They control their temperature by moving in and out of the sun.
Another common rattlesnake in the US is the Eastern Diamondback rattlesnake. This venomous snake grows 33-72″ long. It can be identified by its diamond shaped coloration pattern, dark brown in color. It lives in the woods and dry pinelands of the south. Occasionally it goes into salt water swimming to the Keys off the Florida Coast. Their individual dispositions vary. Some snakes will permit close approach without making a sound while others will rattle when approached 30 or 40 feet away. Many stand their ground but when hard pressed they back away. This snake eats rabbits, rodents, and birds. It’s range is the coastal lowlands form southeast North Carolina to extreme east Louisiana, and all of Florida, including the Florida Keys. It is rapidly becoming extinct however because of Suburban housing and agricultural development annually that destroys it’s habitat.
There are many other species of rattlesnakes roaming the US. One of them is the Canebrake Rattlesnake. This snake is highly venomous and could be deadly. It is mainly brownish gray with a number of very dark bars on the back. It lives in the eastern half of the US and can be found in the woods. It gives birth to approximately 10 live young snakes. Another snake that can only be found in Texas and Arizona is the Banded Rock Rattlesnake. This snake is a highly venomous and bad tempered snake. It will attack for no reason what os ever. Probably one of the most dangerous snakes right after the Diamondbacks. It lives in dry rocky places and feeds on small mammals, lizards, as well as other snakes, even other rattlesnakes. The banded rock comes in many colors.
Although all snakes are portraited as dangerous they are also useful in many ways. For instance their venom can be used to make anti venom and recently scientists discovered that the venom can help cure cancer. In England scientists discovered that a medication partially made from a snake venom slowed down the spread of cancer in animals by 30% making scientists believe that the venom can be used to cure cancer.
Snakes are a very pretty species of animals however they are on a verge of extinction because of the environmental changes caused by humans. Without these reptiles the earth will be in trouble and a lot of changes might happen. People should try and save these beautiful animals because there is no reason not to.
1. Britannica encyclopedia (1997)
2. Encarta Encyclopedia (1995)
3. Grolier Encyclopedia (1997)
4. Webster Encyclopedia (1998)
5. Infopedia.com (2000)
The Encyclopedia of Snakes-by Chris Mattison copyright 1995
Venomous Snakes of the World- by W.P. Mara copyright 1993
Snakes- by Mike Atkinson copyright 1998
Amazing Snakes- by Alexandra Parsons copyright 1990