Snakes

Snakes

Snakes are a very specialized group of Reptiles under order Ophidian. Nearly 3,000 species of snakes are now found in the tropical and sub-tropical parts of the world. Out of these about 300 are Poisonous and others are Non-Poisonous. WHO has estimated that thirty to forty thousand people die annually of a snake bite? Snakes are not found in New Zealand and Ireland.

Snakes

Snakes are slender and elongated reptiles without limbs, eyelids and external ears. The whole body is covered with epidermal scales and shields. The scales and small and usually overlap each other but the shields are large and join each other by their margins. Shields are prominent on the head. The occipital condyle is single and tripartite. The lower jaw is attached to the skull with the help of quadrate which articulates in such a movable fashion that the jaw can move laterally and downwards. The two halves, of the lower jaw, are loosely articulated. All these are a special adaptation for- its peculiar feeding habit.

The teeth are conical, recurred backward and fixed on jaw bones. In poisonous snakes, two maxillary teeth (one on either side) become enlarged and pointed to form the Fangs. There are two types of fangs—open type and closed type according to the nature of the groove.

In poisonous snakes, the labial glands have become modified into poison glands and these do not help them indigestion. The tongue is bifid at the apex. The left lung is reduced. The urinary bladder is absent. Most snakes are terrestrial. Few are arboreal and aquatic.

Some of the poisonous snakes are:

1. Cobra:

There are about 10 species of cobras of which two are found in India. They are Ophiopkagus Hannah and Nana Bungers. Cobra is a very poisonous snake. It is usually found in forests. Usual length is 2-3 meters. The color is black or buff.

The hood is well developed. It is supported by long ribs located just behind the head. The hood bears marks like spectacles. In some cobras, there are two spectacles marks while in others there is a single spectacles mark. Under the neck, there are found 2 or 3 dark belly plates. The fang is an open type.

2. Krait:

Kraits (Nana Burgers) are smaller in size compared to the cobras and measures 1-1-25 meter. The color of the body is glistening black with linear arches. They are found in gardens, on the roof of bung- lows. The poison fangs are small. The shields in the belly are broad. The tail is round at the tip. Central rows of scales down the back are large and hexagonal. The plates under the tail are entire.

3. Vipers:

These are rather large and stout snakes.

The triangular head is broad, flat and covered with small scales. The neck is narrow. Eyes are with the vertically elliptical pupil. The plates in the belly are broad and extend across.
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