The Indian gamma Snake or common cat snake (Boiga trigonata) is a species of rear-fanged colubrid

Colubrid

A colubrid is a member of the snake family Colubridae. This broad classification of snakes includes about two-thirds of all snake species on earth. The earliest species of the snake family date back to the Oligocene epoch. With 304 genera and 1,938 species, Colubridae is the largest snake family...

 found in South Asia

South Asia

South Asia, also known as Southern Asia, is the southern region of the Asian continent, which comprises the sub-Himalayan countries and, for some authorities , also includes the adjoining countries to the west and the east...

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Description

See snake scales

Snake scales

Snakes, like other reptiles, have a skin covered in scales. Snakes are entirely covered with scales or scutes of various shapes and sizes. Scales protect the body of the snake, aid it in locomotion, allow moisture to be retained within, alter the surface characteristics such as roughness to aid in...

 for terms used

B. trigonata has anterior palatine and mandibular teeth scarcely larger than the posterior. Its eyes are as long as the distance from its nostril; the rostral is broader than deep with the internasal scales

Internasal scales

In snakes, the internasal scales are those on top of the head between the scales that surround the nostrils. They are usually paired and situated just behind the rostral....

 shorter than the prefrontal scales

Prefrontal scales

The prefrontal scales on snakes and other reptiles are the scales connected to the frontals towards the tip of the snout which are in contact with the internasals....

. The frontal scales are longer than their distance from the end of the snout and shorter than the parietal scales. The loreals are as long as they are deep, or, they can be deeper than they are long. B. trigonata's one preocular does not extend to the upper surface of the head. The species has two postoculars, temporals 2+3, and 8 upper labials, with the third, fourth, and fifth entering the eye. They can have 4 or 5 lower labials in contact with the anterior chin-shields, which are about as long as the posterior. B. trigonatas body is moderately compressed with scales in 21 (or rarely 19) rows, disposed obliquely, with the vertebrals very feebly enlarged. There are 229-269 ventral scales, 79-92 subcaudul scales, and a single anal scale.

B. trigonata has a yellowish-olive or pale grey colour along the back and a white black-edged zigzag band along the length of the head with two brown bands edged with black, diverging posteriorly. The belly is white and can have a series of small brown spots along each side. The total length is around 3 feet (91 cm) with a 7 inch (18 cm) tail.

B. trigonata is found in the Perso-Baluchistan frontier.

Distribution

It is distributed throughout Sri Lanka

Sri Lanka

Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Pakistan

Pakistan

Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

, Nepal

Nepal

Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...

, Bangladesh

Bangladesh

Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...

, Afghanistan

Afghanistan

Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...

 (Leviton 1959: 461), southern Turkmenistan

Turkmenistan

Turkmenistan , formerly also known as Turkmenia is one of the Turkic states in Central Asia. Until 1991, it was a constituent republic of the Soviet Union, the Turkmen Soviet Socialist Republic . Turkmenistan is one of the six independent Turkic states...

, southern Uzbekistan

Uzbekistan

Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....

, southeastern Tajikistan

Tajikistan

Tajikistan , officially the Republic of Tajikistan , is a mountainous landlocked country in Central Asia. Afghanistan borders it to the south, Uzbekistan to the west, Kyrgyzstan to the north, and China to the east....

, and Iran

Iran

Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...

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The race melanocephala is found in Pakistan; this form is variously considered as a subspecies, color variant, or full species.

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