Mauremys reevesii (Gray, 1831)

Typical Coloration

Mauremys reevesii, commonly known as Reeve's turtle, most commonly has a brown shell, dark grey skin, yellow markings on the neck, and yellow irises.

Melanism in Males

Melanism is well-documented in this species, and only affects mature males over 7 years old: in these males, the entire turtle including the eyes becomes completely black, and all yellow markings are lost.

Female Shell Darkening

Older females may sometimes also develop darker shells with fewer markings.

Megacephaly Occurrence

Some populations of Reeve's turtles can exhibit megacephaly.

Megacephaly Morphology

Megacephalic individuals have much larger, broader heads and hypertrophied jaw muscles.

Megacephaly Cause Hypothesis

In at least one other turtle species, megacephaly does not appear to be genetically linked, and instead develops in response to a heavily durophagous diet.

Native Range

Mauremys reevesii is native to China and Korea.

Introduced Range History

It is thought to have been introduced to Japan and Taiwan in historic times; previously, it was believed to be native to both of these regions.

Japan Introduction Origin

Genetic evidence suggests the species was introduced to Japan from the Korean Peninsula near the end of the 18th century.

Introduced Population Threats

Introduced populations of Mauremys reevesii may threaten native turtles in these regions, because the species readily hybridizes with native species.

Habit Type

Mauremys reevesii is semiaquatic.

Basking Behavior

It basks in the sun on rocks or logs, and will often leave water to engage in this behavior.

Habitat Preferences

It can typically be found in marshes, relatively shallow ponds, streams, and canals with muddy or sandy bottoms.