Atretium schistosum
Encyclopedia
The Split Keelback or Olive keelback snake, Atretium schistosum, is a species of snake
found in South Asia
. It is a common and harmless watersnake.
, India
and Nepal
. In India it occurs in peninsular India south of latitude 15 degrees north
and along the east coast to Uttarakhand
. It is reported to be very common around Bangalore
, North Arcot district (Tamil Nadu
) and Kakinada area in Andhra Pradesh
. Occurs up to 100m above sea level. Absent from most of North India.
The scales are rough because they are keeled. Specimens from South India have a distinct reddish line along the 5th and 6th or the 4th and 5th up to the vent. This line is brighter in the males. The females are between 70 to 75 cm long, and the males between 50 to 60 cm. The longest measured snake is 87 cm long.
The Olive Keelback is found near water or among the surrounding vegetation.
A diurnal snake, it is seen at night also. The snakes rarely bite when handled. It is known to aestivate in the summer.
The olive keelback feeds mainly on frog
s, tadpole
s, fish
and crab
s which it catches with a side-stroke motion that is characteristic of watersnakes. The snake swims past the prey and suddenly snaps its head to the side. The olive keelback is also known to eat mosquito larvae (Whitaker).
Sometimes, referred to as a water-cobra, the olive keelback is nevertheless tolerated by people.
. The eggs, which are white, soft and 30 to 35mm in length, are laid in clutches of 10 to 32 in the months January to April. The newly hatched snakes measure 16.6 to 17.5 cm in length.
Snake
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...
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...
. It is a common and harmless watersnake.
Distribution
Sri LankaSri 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...
and 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...
. In India it occurs in peninsular India south of latitude 15 degrees north
15th parallel north
The 15th parallel north is a circle of latitude that is 15 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, Central America, the Caribbean and the Atlantic Ocean....
and along the east coast to Uttarakhand
Uttarakhand
Uttarakhand , formerly Uttaranchal, is a state in the northern part of India. It is often referred to as the Land of Gods due to the many holy Hindu temples and cities found throughout the state, some of which are among Hinduism's most spiritual and auspicious places of pilgrimage and worship...
. It is reported to be very common around Bangalore
Bangalore
Bengaluru , formerly called Bengaluru is the capital of the Indian state of Karnataka. Bangalore is nicknamed the Garden City and was once called a pensioner's paradise. Located on the Deccan Plateau in the south-eastern part of Karnataka, Bangalore is India's third most populous city and...
, North Arcot district (Tamil Nadu
Tamil Nadu
Tamil Nadu is one of the 28 states of India. Its capital and largest city is Chennai. Tamil Nadu lies in the southernmost part of the Indian Peninsula and is bordered by the union territory of Pondicherry, and the states of Kerala, Karnataka, and Andhra Pradesh...
) and Kakinada area in Andhra Pradesh
Andhra Pradesh
Andhra Pradesh , is one of the 28 states of India, situated on the southeastern coast of India. It is India's fourth largest state by area and fifth largest by population. Its capital and largest city by population is Hyderabad.The total GDP of Andhra Pradesh is $100 billion and is ranked third...
. Occurs up to 100m above sea level. Absent from most of North India.
Description
It is a small, robust snake with thin head, short snout and slit nostrils placed rather high. The snake is olive-green and yellow to orange below. It is sometimes tinged with pink or purplish on the flanks. The length of the tail is one third to one-fourth of the total length.The scales are rough because they are keeled. Specimens from South India have a distinct reddish line along the 5th and 6th or the 4th and 5th up to the vent. This line is brighter in the males. The females are between 70 to 75 cm long, and the males between 50 to 60 cm. The longest measured snake is 87 cm long.
The Olive Keelback is found near water or among the surrounding vegetation.
Identifying characteristics
The snake is distinguished by a number of scale characteristics:- Single internasal.
- Nineteen rows of costals.
- 8 or 9 supralabials (upper lip shields).
Habits
Lives in water or among the surrounding vegetation.A diurnal snake, it is seen at night also. The snakes rarely bite when handled. It is known to aestivate in the summer.
The olive keelback feeds mainly on frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s, tadpole
Tadpole
A tadpole or polliwog is the wholly aquatic larval stage in the life cycle of an amphibian, particularly that of a frog or toad.- Appellation :...
s, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s which it catches with a side-stroke motion that is characteristic of watersnakes. The snake swims past the prey and suddenly snaps its head to the side. The olive keelback is also known to eat mosquito larvae (Whitaker).
Sometimes, referred to as a water-cobra, the olive keelback is nevertheless tolerated by people.
Reproduction
It is oviparous (egg laying). It breeds in the monsoonMonsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
. The eggs, which are white, soft and 30 to 35mm in length, are laid in clutches of 10 to 32 in the months January to April. The newly hatched snakes measure 16.6 to 17.5 cm in length.
Local names
- Kannada – Barmmya.
- TeleguTelugu languageTelugu is a Central Dravidian language primarily spoken in the state of Andhra Pradesh, India, where it is an official language. It is also spoken in the neighbouring states of Chattisgarh, Karnataka, Maharashtra, Orissa and Tamil Nadu...
– Nalla wahlagillee - Sinhala – Diya Warnaya