Balkan terrapin

The Balkan terrapin or western Caspian terrapin (Mauremys rivulata) is a species of terrapin in the family Geoemydidae. It is found in the eastern Mediterranean region. While technically omnivorous, the terrapins are known to prefer meat. They can grow to 25 cm (10 in) in carapace length, although hatchlings are usually only 3 to 4 cm (1.2 to 1.6 in) in length.

Balkan terrapin
Balkan terrapin in captivity
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Superfamily:	Testudinoidea
Family:	Geoemydidae
Genus:	Mauremys
Species:	M. rivulata
Binomial name
Mauremys rivulata (Valenciennes, 1833)[2]
Synonyms[3]
List Emys rivulata Valenciennes, 1833 Emys tristrami Gray, 1869 Emys caspica var. arabica Gray, 1870 Emys pannonica Gray, 1870 Emys tristram Gray, 1873 (ex errore) Emys arabica Gray, 1873 Clemmys caspica orientalis Bedriaga, 1881 Clemmys caspica var. rivulata Boulenger, 1889 Clemmys caspica var. obsoleta Schreiber, 1912 Clemmys caspica cretica Mertens, 1946 Mauremys caspica rivulata Młynarski, 1969 Mauremys rivulata Bour, 1994 Mauremys rivulata rivulata Maran, 1996 Mauremys rivulata tristrami Maran, 1996 Mauremys caspica cretica Bonin, Devaux & Dupré, 1996 Emmenia rivulata Vetter, 2006 Mauremys rivulata cretica Bonin, Devaux & Dupré, 2006

Turtles at the Ein Afek Nature Reserve

Distribution

It is found in the Balkan Peninsula (Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Montenegro, North Macedonia, Serbia), in a number of Mediterranean islands including Crete, Cyprus and Lesvos, and in the Middle East (Israel, Jordan, Lebanon, Syria, Turkey).^[4] On some Greek and Turkish islands where the terrapins are found, they may be threatened with extirpation.^[5]

Physical description

Balkan terrapin emerging from a river

Mauremys rivulata are fairly large, with carapace lengths up to 25 cm (10 in); hatchling turtles of this species are usually between 3 and 4 centimetres (1.2 and 1.6 in) in length.^[5] The average strait^{[clarification needed]} carapace length is roughly 15 cm (6 in); females are slightly larger.^[6][7] The terrapins' carapaces are black to olive green in colour, and the plastron (the shell on the belly) black, although the latter frequently fades as the turtles age. The species also has horizontal yellowish lines running along the neck and limbs.^[7]

Habitat and ecology

The species is mostly lowland, although the terrapins have been recorded as far up as 900 metres (3,000 ft) above sea level. They are found in wetland habitats, including swamps, rivers, and ponds, although they lay their eggs in grassland regions.

Mauremys rivulata are preyed on by large birds and predacious mammals such as mongoose who also feed on the terrapins' eggs, although smaller carnivores may prey on younger turtles with softer shells.^[7]

Diet

Mauremys rivulata is an omnivorous species, eating both plants and animals, although a preference for meat is documented. Young terrapins will eat small invertebrates as well as small amphibian larvae or carcasses; adult terrapins are known also to eat algae and aquatic plants.^[7]

Interactions with humans

Human behaviour affecting the species' habitat has caused population decline.^[8] The largest effects come from urbanisation, water engineering projects, and industrial waste from construction.^[9]

In the northern portion of its range, the species may hibernate during the winter.^[5] Although the terrapins may accept bread offered by humans, they do not have the enzymes needed to digest it, and such offerings are thus bad for their health.^[7]