Friday, March 13, 2009

SNAKES


Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
Class:Reptilia
Order:Squamata
Suborder:Serpentes

Snakes are considered by many as perhaps the most dreadful of all animals that co-inhabit our planet. Fear about snakes prevails due to the total ignorance about these graceful, agile and useful creatures. In India, snakes are part of our mythology, yet, first reaction on seeing a snake is panic, fear and thought to exterminate the species. Non-poisonous snakes do not pose any major problems for humans besides fear and sometimes being pests. Lack of basic knowledge about snakes, leads to `fear of the unknown' and then panic, which further leads to disasterous results.
Snakes, however, play important environmental roles in the fragile ecosystems and can play a very important role in agriculture. They control the population of harmful rodents and pests, thus helping people. Though sometimes dangerous, snakes can be useful, and, as any living creature, they have the right to exist. About Indian Snakes There are about 255 species of snakes in India, of which about 52 are venomous and only four pose threat to human beings, as they are found in the vicinity of human settlements, especially in rural areas which are agricultural and have rats in abundance. The four venomous snakes are called Big Four - Cobra, Common Krait, Russell's Viper and Saw Scaled Viper.
Snakes are elongate legless carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic amniote vertebrates covered in overlapping scales. Like lizards, from which they evolved, they have loosely articulated skulls, and most can dislocate their lower jaw in order to swallow prey much larger than their own head. In order to accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and they have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca.
Living snakes are found on every continent except Antarctica. Fifteen families are currently recognized comprising 456 genera and over 2,900 species. They range in size from the tiny, 10 cm long thread snake to pythons and anacondas of up to 7.6 m (25 ft) in length. The recently discovered fossil Titanoboa was 13 m or 43 ft long. Snakes are thought to have evolved from either burrowing or aquatic lizards during the Cretaceous period (c 150 Ma). The diversity of modern snakes appeared during the Paleocene period (c 66 to 56 Ma).
Most species are non-venomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause painful injury or death to humans.

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