The Balkan terrapin or western Caspian terrapin (''Mauremys rivulata'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

terrapin Terrapins are a group of several species of small turtle (order Testudines) living in freshwater, fresh or brackish water. Terrapins do not form a taxonomic unit and may not be closely related. Many belong to the families Geoemydidae and Emydid ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Geoemydidae The Geoemydidae (formerly known as Bataguridae) are one of the largest and most diverse families in the order Testudines (turtles), with about 70 species A species () is often defined as the largest group of organisms in which any two in ...

. It is found in the eastern Mediterranean region. While technically omnivorous, the terrapins are known to prefer meat. They can grow to in carapace length, although

hatchling In oviparous biology, a hatchling is a newly hatched fish, amphibian, reptile, or bird. A group of mammals called monotremes lay eggs, and their young are hatchlings as well. Fish Fish hatchlings generally do not receive parental care, similar t ...

s are usually only in length.

Distribution

It is found in the

Balkan Peninsula The Balkans ( , ), corresponding partially with the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throug ...

(Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Montenegro, North Macedonia, Serbia), in a number of Mediterranean islands including

Crete Crete ( ; , Modern Greek, Modern: , Ancient Greek, Ancient: ) is the largest and most populous of the Greek islands, the List of islands by area, 88th largest island in the world and the List of islands in the Mediterranean#By area, fifth la ...

Cyprus Cyprus (), officially the Republic of Cyprus, is an island country in the eastern Mediterranean Sea. Situated in West Asia, its cultural identity and geopolitical orientation are overwhelmingly Southeast European. Cyprus is the List of isl ...

and

Lesvos Lesbos or Lesvos ( ) is a Greek island located in the northeastern Aegean Sea. It has an area of , with approximately of coastline, making it the third largest island in Greece and the eighth largest in the Mediterranean. It is separated from A ...

, and in the Middle East (Israel, Jordan, Lebanon, Syria, Turkey). On some Greek and Turkish islands where the terrapins are found, they may be threatened with

extirpation Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with extinction, global extinctions. Local extinctions ...

Physical description

''Mauremys rivulata'' are fairly large, with carapace lengths up to ; hatchling turtles of this species are usually between in length. The average strait carapace length is roughly ; females are slightly larger. The terrapins' carapaces are black to olive green in colour, and the

plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...

(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.

Habitat and ecology

The species is mostly lowland, although the terrapins have been recorded as far up as 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.

Diet

''Mauremys rivulata'' is an

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

species, eating both plants and animals, although a preference for meat is documented. Young terrapins will eat small

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s as well as small

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

larvae or carcasses; adult terrapins are known also to eat algae and aquatic plants.

Interactions with humans

Human behaviour affecting the species' habitat has caused population decline. The largest effects come from

urbanisation Urbanization (or urbanisation in British English) is the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It can also ...

, water engineering projects, and

industrial waste Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, mills, and mining operations. Types of industrial waste include dirt and ...

from construction. In the northern portion of its range, the species may hibernate during the winter. Although the terrapins may accept bread offered by humans, they do not have the

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s needed to digest it, and such offerings are thus bad for their health.

References

{{Taxonbar, from=Q1504849 Mauremys Turtles of Asia Turtles of Europe Reptiles of Cyprus Reptiles of Syria Reptiles of Turkey Reptiles described in 1833 Taxa named by Achille Valenciennes