About Pelodiscus sinensis Wiegmann, 1835
Pelodiscus sinensis, commonly known as the Chinese softshell turtle, shows sexual size dimorphism: females can reach a maximum straight-line carapace length of 33 cm (13 in), while males are smaller at up to 27 cm (11 in), and have longer tails than females. Sexual maturity is reached when the turtle's carapace measures 18–19 cm (7.1–7.5) in length, which occurs between 4 and 6 years of age. It has webbed feet adapted for swimming. It gets the "softshell" name because its carapace does not have horny scutes (scales). Instead, the carapace is leathery and pliable, especially along the sides. Like other turtles, it has a layer of solid bone beneath the central part of the carapace, but this bone layer is absent from the outer edges of the carapace. The light, flexible shell lets this turtle move more easily both in open water and on muddy lake bottoms. The carapace of P. sinensis is olive-colored and may have dark blotches. Its plastron is orange-red, and may also have large dark blotches. The limbs and head are olive on the dorsal side; the forelimbs are lighter, while the hind limbs are orange-red on the ventral side. The head has dark flecks, with dark lines that radiate out from the eyes. The throat is mottled, and there may be small, dark bars on the lips. There is a pair of dark blotches in front of the tail, along with a black band on the posterior side of each thigh. The Chinese softshell turtle is native to Taiwan and China, where it occurs in Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hong Kong, Hubei, Hunan, Inner Mongolia (Nei Mongol), Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Yunnan, and Zhejiang Provinces. Populations that were originally included in this species from Northeast China, Russia, Korea, and Japan are now classified as a separate species, the Amur softshell turtle (P. maackii). Populations from Vietnam and Hainan Island are now recognized as the spotted softshell turtle (P. variegatus). Additionally, localized populations in Guangxi, Hunan, and Anhui (where the Chinese softshell turtle also occurs) are now recognized as separate species: the lesser Chinese softshell turtle (P. parviformis), the Hunan softshell turtle (P. axenaria), and the Huangshan softshell turtle (P. huangshanensis). It is hard to determine the exact native range of the Chinese softshell turtle, because it has a long history of use as food and herbal medicine, and has been spread by migrating human populations. Outside its native range in China, escaped individuals have been recorded in many countries, and some of these populations have become established as introduced populations. Non-native locations in Asia include: the Bonin Islands, Honshu, Kyushu, Ryukyu Archipelago, and Shikoku in Japan; South Korea; Laos; Vietnam; Thailand; Singapore; Bohol, Cebu, Leyte, Luzon, Mindanao, Mindoro, and Panay in the Philippines; East and Peninsular Malaysia; Kalimantan, Sumatra, and West Timor in Indonesia; East Timor; and Iran. Outside Asia, recorded non-native locations include Pará in Brazil; Spain; and Guam, the Northern Mariana Islands, and Oahu (Hawaii) in the United States. In areas where it is not native, the Chinese softshell turtle is an invasive pest that endangers various native species and disrupts many ecosystems. In 2024, this species was found in the Merrimack River in Massachusetts. The Chinese softshell turtle inhabits fresh and brackish water. In China, it is found in slow-current rivers, lakes, ponds, canals, and creeks; in Hawaii, it can be found in marshes and drainage ditches. During mating, which takes place either at the water surface or underwater, a male will hold the female's carapace with his forelimbs, and may bite her head, neck, and limbs. Females can retain sperm for nearly a year after copulation. Females lay clutches of 8 to 30 eggs, and may lay 2 to 5 clutches per year. Eggs are laid in a nest with an entrance around 76–102 mm (3–4 in) across. The eggs are spherical, with an average diameter of about 20 mm (0.79 in). Eggs hatch after an incubation period of roughly 60 days; the incubation time can be longer or shorter depending on temperature. Average hatchlings have a carapace length and width both of about 25 mm (1 in). The sex of Chinese softshell turtle hatchlings is not determined by incubation temperature.
