The northern river terrapin (''Batagur baska'') is a species of riverine

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked t ...

native to Southeast Asia. It is classified Critically Endangered by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

and considered extinct in much of its former range.

Description

The northern river terrapin is one of Asia's largest freshwater and brackwater turtles, reaching a carapace length of up to 60 cm and a maximum weight of 18 kg. Its

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is moderately depressed, with a

vertebral The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordates ...

keel in juveniles. The plastron is large, strongly angulate laterally in the young, convex in the adult. The head is rather small, with a pointed and upwards-tending snout. The legs have band-like scales. The upper surface of the carapace and the soft parts are generally olive-brown, while the plastron is yellowish. Head and neck are brown with reddish bases. Males in breeding coloration have a black head and neck with a crimson or orange dorsal surface and red or orange forelegs. The colour of the pupils also changes during this period, to brown in females and yellow-white in males. During the breeding season, the color of the pupils of a female brown whereas the pupils in the males become yellowish-white. Two subspecies are recognized: ''B. b. baska'' (Gray, 1831) and ''B. b. ranongensis'' (Nutaphand, 1979).

Distribution and habitat

The species is currently found in

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mo ...

and

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

(in the

Sunderbans Sundarbans (pronounced ) is a mangrove area in the delta formed by the confluence of the Padma, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans the area from the Baleswar River in Bangladesh's division of Khulna to the Hooghly ...

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...

and

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federal constitutional monarchy consists of thirteen states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia and Borneo's East Mal ...

. It is regionally extinct in

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

and

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making ...

. It is strongly aquatic but uses terrestrial nesting sites, frequenting the tidal areas of estuaries, large rivers, and mangrove forests.

Ecology

The northern river terrapin is omnivorous, taking waterside plants and small animals such as clams. The species prefers freshwater habitats and moves to brackish river mouths or estuaries in the breeding season (December–March), returning after laying their eggs. Individuals have been known to undertake long seasonal migrations of 50 to 60 miles to the sand banks where they were hatched. Females usually lay three clutches of 10-34 eggs each.

Conservation

The species is considered Critically Endangered by the

, principally due to exploitation as a food item (including egg harvesting). Previously, immense numbers were shipped into the fish markets of

Calcutta Kolkata (, or , ; also known as Calcutta , the official name until 2001) is the capital of the Indian state of West Bengal, on the eastern bank of the Hooghly River west of the border with Bangladesh. It is the primary business, commer ...

from throughout

; among the Bengali Hindus, the river terrapin was considered the most delectable of all turtles. It is still illegally exported from

and traded in large numbers in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. Loss of nesting beaches and pollution are also impacting the species. A hatchery and captive breeding project was established in Vawal National Park at

Gazipur Gazipur ( bn, গাজীপুর) is a city in central Bangladesh. It is located in the Gazipur District. It is a major industrial city north of Dhaka. It is a hub for the textile industry in Bangladesh. Its other name is Joydebpur. Demogr ...

and another in Sajnekhali Forest Station in the Sunderban Tiger Reserve in India with support from Turtle Survival Alliance.

References

External links

Centre for Turtle Research and Conservation
* {{Taxonbar, from=Q810705 Reptiles of Myanmar Fauna of Southeast Asia Reptiles of Indonesia Reptiles of Thailand Reptiles of India Batagur Reptiles described in 1830 Taxa named by John Edward Gray