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.