Hybridization of geoemydid turtles has been frequently reported from East Asia among closely related species in the wild and in captivity. In recent surveys of the aquatic freshwater turtles in Taiwan, at least 10 putative hybrid turtles have been found in the wild or in markets. Most cases are presumed to be interspecific hybrids of Mauremys species. Their morphological characteristics are intermediate suggesting that they are hybrids among closely related species; however high variation in morphology indicates that they might be derived from multiple hybridization introgressions. In a case from northern Taiwan, a hybrid female is confirmed to be viable and fertile, and can lay more clutches of eggs than its related parental species
(Mauremys reevessii and M. sinensis) in its outdoor enclosure. The hybrid offspring are also fertile and can mature and reproduce earlier than their parental species. The findings of this high reproductive potential in hybrid turtles raises concern that the hybridization event may be not so unusual as regarded and the intentional breeding practice in the pet market may facilitate the genetic pollution among related species.