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Chinese softshell turtle
Chinese softshell turtle
Chinese softshell turtle
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Not to be confused with northern Chinese softshell turtle or lesser Chinese softshell turtle.

Chinese softshell turtle
CITES Appendix II [3]
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Trionychidae
Genus: Pelodiscus
Species:
P. sinensis
Binomial name
Pelodiscus sinensis
(Wiegmann, 1835)[1]
Synonyms

See text

The Chinese softshell turtle[1] (Pelodiscus sinensis) is a species of softshell turtle that is native to mainland China (Inner Mongolia to Guangxi, including Hong Kong) and Taiwan, with records of escapees—some of which have established introduced populations—in a wide range of other Asian countries, as well as Spain, Brazil and Hawaii.[4]

Populations native to Northeast China, Russia, Korea and Japan were formerly included in this species, but are now regarded as separate as the northern Chinese softshell turtle (P. maackii). Furthermore, localized populations in Guangxi and Hunan (where the Chinese softshell turtle also is present), as well as Vietnam, are recognized as the lesser Chinese softshell turtle (P. parviformis) and Hunan softshell turtle (P. axenaria).[5]

The Chinese softshell turtle is a vulnerable species,[5] threatened by disease, habitat loss, and collection for food such as turtle soup. Additionally, millions are now farmed, especially in China, to support the food industry,[6] and it is the world's most economically important turtle.[7]

Description

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Basking, in Taiwan

Females of the Chinese softshell turtle can reach a straight-line carapace length of up to 33 cm (13 in) while the smaller males reach 27 cm (11 in), with longer tails than the females.[8] Sexual maturity is reached at a carapace length of 18–19 cm (7.1–7.5 in).[8]

It has webbed feet for swimming. It is called "softshell" because its carapace lacks horny scutes (scales). The carapace is leathery and pliable, particularly at the sides. The central part of the carapace has a layer of solid bone beneath it, as in other turtles, but this is absent at the outer edges. The light and flexible shell of this turtle allows it to move more easily in open water, or in muddy lake bottoms.[9]

The carapace of P. sinensis is olive in color and may have dark blotches. The plastron is orange-red, and may also have large dark blotches. The limbs and head are olive dorsally with the forelimbs lighter and the hind-limbs orange-red ventrally. There are dark flecks on the head and dark lines that radiate from the eyes. The throat is mottled and there may be small, dark bars on the lips. A pair of dark blotches is found in front of the tail as well as a black band on the posterior side of each thigh.[10]

Juvenile

Distribution and habitat

[edit]
Pelodiscus sinensis

Distribution

[edit]

The Chinese softshell turtle is native to Taiwan and China, where it is found 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.[5]

Populations native to Northeast China, Russia, Korea and Japan were formerly included in this species, but are now regarded as separate as the Amur softshell turtle (P. maackii). Populations in Vietnam and Hainan Island are now recognized as the spotted softshell turtle (P. variegatus). Furthermore, localized populations in Guangxi, Hunan, and Anhui (where the Chinese softshell turtle also is present) are recognized as the lesser Chinese softshell turtle (P. parviformis), Hunan softshell turtle (P. axenaria), and Huangshan softshell turtle (P. huangshanensis).[5]

It is difficult to determine the exact native range of the Chinese softshell turtle due to the long tradition of its use as a food and herbal medicinal,[11] and subsequent spread by migrating people.[10] Outside its native China, escapees have been recorded in a wide range of countries and some of these have becomes established as introduced populations. Among the non-native locations in Asia are 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.[5] Outside Asia, locations include Pará in Brazil; Spain; and Guam, Northern Mariana Islands and Oahu (Hawaii) in the United States.[5][12] In the places where the Chinese softshell turtle is not native, the species has become a pest and invasive species, endangering various indigenous species in areas where it has been introduced and destabilizing numerous ecosystems.[13][14] In 2024, the species was found in the Merrimack River in Massachusetts.[15]

Habitat

[edit]

The Chinese softshell turtle lives in fresh and brackish water.[16][17] In China it is found in rivers, lakes, ponds, canals and creeks with slow currents, and in Hawaii they can be found in marshes and drainage ditches.[10]

Ecology and behavior

[edit]

Diet

[edit]

P. sinensis is predominantly carnivorous and the remains of fish, crustaceans, mollusks, insects, and seeds of marsh plants have been found in its stomach.[10]

Movement

[edit]

With its long snout and tubelike nostrils, the Chinese softshell turtle can "snorkel" in shallow water.[18] When resting, it lies at the bottom, buried in sand or mud, lifting its head to breathe or snatch at prey. Its basking habit is not well developed.[10]

The Chinese softshell turtle often submerges its head in water.[18] This is because the species carries a gene which produces a protein that allows it to secrete urea from their mouths. This adaptation helps it to survive in brackish water by making it possible for it to excrete urea without drinking too much salty water. Rather than eliminating urea by urinating through its cloaca as most turtles do, which involves significant water loss, it simply rinses its mouth in the water.[17]

When provoked, certain populations of P. sinensis are capable of excreting a foul smelling fluid from pores on the anterior edge of their shells.[19]

Life cycle

[edit]
At Chitose Aquarium in Hokkaido, Japan

The Chinese softshell turtle reaches sexual maturity sometime between 4 and 6 years of age. It mates at the surface or under water. A male will hold the female's carapace with its forelimbs and may bite at her head, neck, and limbs. Females may retain sperm for almost a year after copulation.[10]

The females lay 8–30 eggs in a clutch and may lay from 2 to 5 clutches each year. The eggs are laid in a nest that is about 76–102 mm (3–4 in) across at the entrance. Eggs are spherical and average about 20 mm (0.79 in) in diameter. After an incubation period of about 60 days, which may be longer or shorter depending upon temperature, the eggs hatch. Average hatchling carapace length is about 25 mm (1 in) and width is also about 25 mm (1 in).[10] Sex of the hatchlings is not determined by incubation temperature.[19]

Diseases

[edit]

In the intensive aquacultural industry the Chinese softshell turtle is increasingly vulnerable to multiple bacterial diseases.[20] In 2012 the Chinese soft-shell turtle was the first turtle species to undergo a large-scale outbreak of bacterial softshell disease, resulting in slower growth and increased fatality. This lead not only to a decline in P. sinensis, but caused severe economic losses to the turtle culture industry.[20] Aeromonas spp., Citrobacter freundii, and Edwardsiella tarda have all been identified as the most significant causative bacterial organisms.[21] Other bacterial pathogens identified have been Chryseobacterium spp., Morganella morganii and Bacillus cereus spp..[22]

Conservation

[edit]

Wild populations are listed as vulnerable on the IUCN Red List.[2] In contrast, the mass farming and release of P. sinensis has been known to lead to hybridization producing several other unique Pelodiscus lineages, some of which may be distinct species, which in turn threaten the gene pool.[23]

Relations with humans

[edit]
Being sold in Seoul, South Korea
Turtle blood mixed with sake in Japan
Global aquaculture production of Chinese softshell turtle (Trionyx sinensis) in thousand tonnes from 1990 to 2022, as reported by the FAO[24]

The Chinese softshell turtle is the most commonly raised species in China's turtle farms.[16][25] According to the data obtained from 684 Chinese turtle farms, they sold over 91 million turtles of this species every year; considering that these farms represented less than half of the 1,499 registered turtle farms in China, the nationwide total could be over twice as high.[6] The Chinese softshell turtle is considered a delicacy in many parts of Asia.[18] Turtle soup is made from this species. In Japan, it may be stewed with hōtō noodles and served as a winter delicacy. Many Koreans, even today, generally have a taboo against eating turtles which has origins in native Korean shamanism.

P. sinensis can be injured if it is dropped or hit, and is susceptible to shell fungus. Captives of this species will eat canned and fresh fish, canned dog food, raw beef, mice, frogs, and chicken. However, in captivity it does not usually eat turtle feed.[10] It can deliver a painful bite if provoked, but will usually let go after a while.

Cultural depictions

[edit]

In a 2018 interview with Le Monde, Nintendo character designer Yōichi Kotabe stated that the Chinese softshell turtle inspired the design for Bowser, the main antagonist of the Mario franchise. Kotabe chose the species because of its aggressive nature.[26]

Synonyms

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Numerous synonyms have been used for this species:[27]

  • Testudo rostrata Thunberg, 1787 (nomen suppressum)
  • Testudo striata Suckow, 1798
  • Testudo semimembranacea Hermann, 1804 (nomen suppressum et rejectum)
  • Emydes rostrata – Brongniart, 1805
  • Trionyx (Aspidonectes) sinensis Wiegmann, 1834 (nomen conservandum)
  • Trionyx japonicus – Temminck & Schlegel, 1835
  • Trionyx tuberculatus Cantor, 1842
  • Pelodiscus sinensis – Fitzinger, 1843
  • Tyrse perocellata Gray, 1844
  • Trionyx perocellatus – Gray, 1856
  • Trionyx schlegelii Brandt, 1857
  • Potamochelys perocellatus – Gray, 1864
  • Potamochelys tuberculatus – Gray, 1864
  • Landemania irrorata Gray, 1869
  • Landemania perocellata – Gray, 1869
  • Trionyx peroculatus Günther, 1869 (ex errore)
  • Gymnopus perocellatus – David, 1872
  • Gymnopus simonii David, 1875 (nomen nudum)
  • Ceramopelta latirostris Heude, 1880
  • Cinctisternum bicinctum Heude, 1880
  • Coelognathus novemcostatus Heude, 1880
  • Coptopelta septemcostata Heude, 1880
  • Gomphopelta officinae Heude, 1880
  • Psilognathus laevis Heude, 1880
  • Temnognathus mordax Heude, 1880
  • Trionyx sinensis newtoni Bethencourt-Ferreira, 1897
  • Tortisternum novemcostatum Heude, 1880
  • Temnognanthus mordax – Boulenger, 1889
  • Tyrse sinensis – Hay, 1904
  • Amyda japonica – Stejneger, 1907
  • Amyda schlegelii – Stejneger, 1907
  • Amyda sinensis – Stejneger, 1907
  • Amyda tuberculata – Schmidt, 1927
  • Trionyx sinensis sinensis – Smith, 1931
  • Trionyx sinensis tuberculatus – Smith, 1931
  • Amyda schlegelii haseri Pavlov, 1932
  • Amyda schlegelii licenti Pavlov, 1932
  • Amyda sinensis sinensis – Mertens, Müller & Rust, 1934
  • Amyda sinensis tuberculata – Mertens, Müller & Rust, 1934
  • Trionyx schlegeli Chkhikvadze, 1987 (ex errore)
  • Trionix sinensis – Richard, 1999
  • Pelodiscus sinensis sinensis – Ferri, 2002
  • Pelodiscus sinensis tuberculatus – Ferri, 2002
  • Pelodiscus sinensis japonicus – Joseph-Ouni, 2004

Genetics

[edit]

The genome of Pelodiscus sinensis was sequenced in 2013 to examine the development and evolution of the softshell turtle body plan.[28]

References

[edit]

Bibliography

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[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Chinese softshell turtle

View on Grokipedia
from Grokipedia
The Chinese softshell turtle (Pelodiscus sinensis), a medium-sized freshwater in the family , is distinguished by its soft, leathery, olive-gray to greenish-brown lacking the hard scutes typical of most , with juveniles often featuring yellow-bordered black spots that fade in adults. Females grow larger than males, reaching lengths of up to 250 mm, while males exhibit longer tails and necks; both sexes have a snorkel-like for breathing at the water's surface. Native to , including eastern , , Korea, , extreme southeastern , and , this species prefers lowland freshwater habitats such as rivers, lakes, ponds, and wetlands, where it burrows into mud or sand for concealment and . It has been introduced to regions like , the , and parts of through the pet and food trades, establishing feral populations in some areas due to its adaptability to disturbed waterways. As an opportunistic , it preys on , , crustaceans, and mollusks, using its tubular and expansive mouth to ambush prey while largely aquatic; it occasionally basks on land or riverbanks to regulate body temperature. Reproductively prolific, females lay multiple clutches of 10–30 eggs per year in sandy or gravelly nests during the warmer months following heavy rains, with incubation occurring at temperatures of 25–32°C; the species is widely farmed in for its and medicinal uses, supporting a significant industry. However, wild populations face severe declines from , degradation, , and collection for the trade, leading to its classification as Vulnerable on the . Conservation efforts include protection, though challenges persist due to the species' cultural and economic value.

Taxonomy and nomenclature

Classification

The Chinese softshell turtle (Pelodiscus sinensis) belongs to the kingdom Animalia, phylum Chordata, class Reptilia, order Testudines, suborder Cryptodira, superfamily Trionychoidea, family Trionychidae, subfamily Trionychinae, genus Pelodiscus, and species sinensis. This placement situates it among the hidden-necked turtles, characterized by their ability to retract the head into the shell in a vertical S-shaped curve. The family, encompassing softshell turtles like P. sinensis, represents an ancient lineage with fossil records extending to the , originating likely in before dispersing across . Pan-trionychids, the broader including modern Trionychidae, dominated turtle faunas from the onward, highlighting the family's evolutionary persistence amid major geological changes. Within the genus Pelodiscus, P. sinensis is differentiated from congeners such as P. axenaria and P. maackii through distinct morphological traits, including shell patterns and osteological features, corroborated by genetic evidence from mitochondrial DNA sequences that reveal deep phylogenetic divergences. These analyses confirm P. axenaria and P. maackii as valid species, separate from the P. sinensis complex, based on diagnosable cytochrome b haplotypes and nuclear markers. Subsequent studies have further refined the complex, describing additional species including P. variegatus (2019), P. huangshanensis (2021), and P. shipian (2022).

Synonyms and etymology

The scientific name Pelodiscus sinensis reflects the turtle's ecological adaptations and geographic origin. The genus name Pelodiscus is derived from pēlos (mud or mire) and diskos (disc), alluding to the species' habit of dwelling in muddy substrates and its flattened, disc-like carapace. The specific epithet sinensis is Latin for "Chinese," denoting the turtle's native range in . The species was first described by Arend Friedrich August Wiegmann in 1835 under the name Trionyx (Aspidonectes) sinensis, based on a specimen from a small in the Xi Jiang () near Macao, . In the same year, Leopold Fitzinger established the Pelodiscus with P. sinensis as the , marking an early taxonomic separation from the broader Trionyx . Subsequent revisions in the , including synonymizations by Friedrich Siebenrock in 1907, consolidated many junior synonyms under Pelodiscus sinensis to address the species' morphological variability across its range. Key synonyms include:
  • Trionyx sinensis Wiegmann, 1835
  • Potamochelys novemcostata Gray, 1864
  • Amyda sinensis (Wiegmann, 1835)
These names arose from early descriptions of regional variants, but phylogenetic studies in the 21st century have prompted further refinements, restricting P. sinensis to specific lineages while elevating others to species status.

Physical characteristics

Morphology

The Chinese softshell turtle (Pelodiscus sinensis) exhibits a distinctive morphology adapted to its lifestyle, featuring a soft, leathery and plastron devoid of the keratinous scutes found in hard-shelled turtles. The is round to oval in shape, typically olive-gray to greenish-brown in coloration, often marked with dark vermiculations or spots that provide against muddy substrates; juveniles display more prominent yellow-bordered black spots, which fade in adults. The plastron is similarly flexible and leathery, pale white to yellowish underneath, with well-developed buttresses that articulate with the for structural support. The head and neck are elongated and highly retractable, enabling the turtle to withdraw into the shell for protection. A prominent tubular snout, or proboscis, extends from the head, functioning like a snorkel to allow respiration at the water surface while the body remains submerged or buried in sediment. The eyes are small and laterally positioned, suited to low-light aquatic environments, complemented by a well-developed olfactory system with over 1,000 odorant receptor genes and numerous olfactory receptor neurons (up to 23 million in the lower chamber epithelium), enhancing chemosensory detection in turbid waters. The limbs are robust with fully webbed feet, facilitating efficient propulsion through water, while the overall body lacks rigid bony plates, prioritizing flexibility and rapid movement over armored defense. Internally, P. sinensis relies on pulmonary respiration via lungs but supplements this with accessory mechanisms during prolonged submersion or burial, including buccopharyngeal respiration—pumping water over vascularized pharyngeal tissues—and through the permeable leathery skin, which accounts for a significant portion of oxygen uptake. In addition to respiration, the buccopharyngeal cavity plays a key role in excretion, with P. sinensis excreting a major portion of its urea—approximately 94%—through its mouth via buccopharyngeal urea excretion, rather than through the kidneys. This process involves buccopharyngeal villiform processes and rhythmic pharyngeal movements, facilitated by urea transporters in the buccopharyngeal epithelium, allowing the turtle to eliminate nitrogenous waste by submerging its head in water for 20-100 minutes. This adaptation conserves water and enables survival in brackish or low-water environments. These adaptations allow the turtle to remain active underwater for extended periods without surfacing, particularly when ambushing prey or evading threats by burrowing into mud. While cloacal structures are present, P. sinensis primarily relies on pharyngeal and dermal exchange rather than cloacal respiration during burial.

Size and sexual dimorphism

The Chinese softshell turtle (Pelodiscus sinensis) exhibits marked , with females generally larger and more robust than males to support egg production and overall reproductive capacity. Adult females can attain a maximum carapace length of 25 cm (250 mm), while males reach up to 20 cm; large females may weigh up to 5 kg, reflecting their greater body mass and structural development. In addition to size differences, males possess thicker tails for reproductive functions and a slightly concave plastron that facilitates mounting during , contrasting with the flatter plastron of females. These morphological traits become evident as individuals approach , typically at around 18-19 cm length for both sexes, though females continue growing more substantially thereafter. Growth in P. sinensis is rapid during the juvenile phase, with annual carapace length increases of up to 10 cm in the first few years under optimal aquaculture conditions, before slowing considerably in adults to rates of approximately 0.2–0.5 cm per month. This pattern is influenced by environmental factors such as water temperature, which optimally ranges from 25-30°C for maximal growth, and food availability, with nutrient-rich diets accelerating development in captive populations.

Distribution and habitat

Native range

The Chinese softshell turtle (Pelodiscus sinensis) is native to central and eastern , including provinces such as , , , , , , , , , , , , , and , as well as and . This distribution reflects its adaptation to diverse freshwater systems across these regions. Note that populations in northern (e.g., , ) are now classified as a separate species, Pelodiscus maackii. Historical range contraction has occurred due to human activities, particularly overharvesting for food and as well as habitat degradation, leading to sharp declines in wild populations—over 95% in some areas—with core remaining populations concentrated in the Yangtze River basin.

Introduced populations

The Chinese softshell turtle (Pelodiscus sinensis) has been introduced to various regions outside its native range in primarily through the pet trade, for and , and intentional releases by immigrants. These human-mediated translocations have led to established wild populations in select areas, while many introductions remain sporadic or unestablished. In the United States, the species was first introduced to in the 1800s by Asian immigrants seeking a source, resulting in self-sustaining populations on islands such as Kauai and Oahu. Introductions to the mainland, including via the pet trade and cultivation attempts, have occurred but have not led to widespread establishment, with only isolated records reported. In , P. sinensis has been introduced mainly through releases of pet turtles that outgrow or prove difficult to manage due to their aggressive behavior and size. Established populations exist in the marshes of the River in southern , while recent records indicate introductions in (e.g., near along the ) and (e.g., Quellsee near and Gübsensee near St. Gallen), often in ponds connected to river systems. In the , sporadic sightings from pet releases have been documented, though no breeding populations are confirmed. Southeast Asian countries beyond the native range, such as the (including and other islands) and (, , and ), host introduced populations stemming from escapes and food farming initiatives dating back to the mid-20th century. In , introductions to the state of in the Amazon region have been recorded, potentially establishing in local wetlands through releases from ornamental or food trades, though confirmation of reproduction remains limited. These non-native distributions contrast with the species' indigenous occurrence in rivers and lakes of and , highlighting the role of global trade in facilitating spread.

Habitat preferences

The Chinese softshell turtle (Pelodiscus sinensis) inhabits primarily slow-moving or stagnant freshwater environments, including lowland rivers, lakes, ponds, canals, marshes, and rice paddies, where soft, muddy substrates predominate. These conditions allow the species to exploit shallow, vegetated waters with low flow rates, which support its and needs. While predominantly a freshwater species, P. sinensis exhibits tolerance for brackish conditions up to 15 ppt for short durations, enabling occasional incursions into estuarine or coastal habitats, though it actively avoids fast-flowing currents and deep, open waters that exceed its physiological limits. This tolerance is facilitated by its unique ability to excrete urea primarily through the mouth (buccopharyngeal excretion), allowing it to eliminate waste without ingesting excessive amounts of saline water and thereby enhancing its adaptability to varied freshwater and slightly saline environments. In microhabitats, individuals into loose at the water bottom, a essential for predation on passing prey and for by maintaining stable body temperatures in fluctuating aquatic environments. Females further require accessible sandy or muddy banks with sparse for nesting, where they excavate shallow cavities to deposit eggs during the reproductive season.

Ecology and behavior

Diet and foraging

The Chinese softshell turtle (Pelodiscus sinensis) is primarily carnivorous but omnivorous in practice, with its diet consisting mainly of aquatic prey such as , crustaceans including and , , mollusks, and other like . It occasionally consumes amphibians such as frogs and plant matter, including seeds of marsh plants; analyses of contents indicate plant material occurs in at least 50% of samples. As an , P. sinensis typically buries itself in the soft substrate of rivers, lakes, or marshes, protruding only its eyes and elongated, proboscis-like to breathe and detect prey. It remains largely sedentary and buried for most of the day, striking rapidly with its long neck to capture passing prey, and also engages in opportunistic scavenging of carrion when available. This bottom-dwelling strategy allows it to conserve energy while exploiting abundant aquatic resources in its habitat. Dietary preferences exhibit ontogenetic shifts, with juveniles focusing more on smaller invertebrates such as insects and zooplankton due to their size limitations, while adults incorporate larger vertebrate prey like fish and amphibians into their diet. These shifts reflect developmental changes in body size and digestive capabilities, enabling adults to handle more diverse and substantial food items without a major transition to herbivory.

Locomotion and daily activity

The Chinese softshell turtle (Pelodiscus sinensis) is predominantly aquatic, relying on its fully webbed limbs to generate powerful paddling propulsion for swimming through rivers, lakes, and other freshwater habitats. These adaptations enable efficient movement in water, where the turtle spends most of its time foraging and resting. On land, locomotion is limited to short distances, primarily for sunbathing to regulate body temperature or nesting, after which individuals quickly return to water. Daily activity patterns vary with environmental conditions; the species exhibits both diurnal and nocturnal behaviors, with and other activities observed during day and night in warm periods. To avoid excessive heat and predation in hot climates, turtles often into the substrate or remain buried at the bottom of their aquatic habitat for much of the day, emerging more actively or dusk. Seasonal movements are limited, with higher daily distances (up to 59 m on average in peak months like May) correlating positively with warmer water temperatures, while activity drops sharply in winter (to about 0.4 m per day). Individuals maintain a home range typically spanning several hundred meters along river channels, up to approximately 1 km in linear extent, shifting to deeper waters during colder periods for protection.

Reproduction and life cycle

The breeding season for the Chinese softshell turtle (Pelodiscus sinensis) typically spans from spring to late autumn in its native range, with mating occurring in aquatic environments at the water surface or underwater. Males may exhibit courtship behaviors involving physical contact, such as biting or grasping the female's head, though detailed observations of these interactions remain limited in wild populations. Females can store viable sperm for up to six months after copulation (and longer in the oviduct), enabling delayed fertilization and multiple clutches without repeated mating. Nesting occurs primarily during periods of heavy rainfall, when females excavate burrows in sandy or muddy riverbanks, creating flask-shaped nests approximately 10-15 cm deep and 4-5 cm in diameter at the entrance. Each clutch contains 3-28 eggs, with a mean of around 20, and eggs are spherical, measuring 17-20 mm in diameter and weighing approximately 5.4–6.5 g. Females produce 2-5 clutches per season, with larger individuals (4,000-5,000 g body weight) capable of up to 4-5 clutches annually, and they are ready to mate again 5-7 days after laying. Eggs incubate for 48-68 days, with the duration influenced by environmental ; optimal hatching occurs at 28-33°C, where higher temperatures accelerate development and result in larger hatchlings, though incubation does not determine , as P. sinensis follows a genetic ZZ/ZW system. Hatchlings emerge at approximately 3 cm in length, measuring about 2.5-3 cm across, and are independent immediately upon hatching, feeding on small . is reached at 5-6 years of age, with females maturing slightly later than males, often at a length of 15-20 cm. In the wild, individuals typically live 25-30 years, though lifespan can vary based on habitat quality and predation pressure.

Hibernation and seasonal adaptations

The Chinese softshell turtle (Pelodiscus sinensis) enters a state of hibernation, also known as overwintering or brumation, typically from late October or November to March or early April, lasting approximately four months in its native range. During this period, the turtle buries itself in mud or soil burrows along riverbanks or in aquatic substrates to conserve energy amid cold temperatures and food scarcity. Hibernation sites are selected for stability, with individuals preferring moist, vegetated areas such as dense stands of Acorus calamus near water bodies, where the dorsal carapace is buried about 5 cm deep. These locations maintain soil or water temperatures above freezing (typically >0°C to 8°C) and humidity levels exceeding 30%, protecting against desiccation and extreme cold. Physiological adaptations enable survival during , including a drastic reduction in metabolic rate, , and respiratory frequency to minimize expenditure. Oxygen uptake shifts primarily to cutaneous () respiration, supplemented by pharyngeal in terrestrial burrows where the may protrude slightly for air access. Pre-hibernation fat accumulation in the liver and provides essential reserves, with lipid breakdown via sustaining the turtle through the dormant phase. Studies indicate that hepatic lipid droplets decrease significantly during , reflecting efficient mobilization of stored s. Emergence from is triggered by rising ambient temperatures and warming waters in spring, often occurring around late when conditions support active . Recent research highlights selective use for microenvironments with high and stable thermal profiles, underscoring the turtle's adaptations to seasonal variability for overwintering success. These strategies allow P. sinensis to endure prolonged low-oxygen and hypothermic conditions without feeding.

Health and threats

Diseases and parasites

The Chinese softshell turtle (Pelodiscus sinensis) is susceptible to various bacterial infections, particularly in settings with poor water quality. Shell rot, characterized by ulceration and decay of the or plastron, is commonly caused by Aeromonas sobria and A. caviae, leading to necrotic lesions and high mortality if untreated. Other bacterial pathogens, such as , induce hemorrhagic septicemia and red spot disease, manifesting as skin ulcers, red discoloration, and internal organ enlargement, often exacerbated by high stocking densities and polluted environments. Fungal infections, such as saprolegniasis caused by spp., can also affect stressed individuals in cool, damp conditions. Viral infections pose significant threats, with the soft-shelled turtle iridovirus (STIV), a member of the Ranavirus genus, causing red neck disease and systemic septicemia in farmed populations. Symptoms include hyperemia of the neck and limbs, lethargy, and hemorrhaging, resulting in mass die-offs with mortality rates exceeding 80% during outbreaks. Ranavirus infections, including STIV, are associated with the in live animals, which can facilitate spread. Parasitic infestations are prevalent, especially in polluted habitats where intermediate hosts proliferate. Trematodes such as Coeuritrema platti and Leurosoma baiyangdiensis infect the blood vessels and intestines, causing anemia, tissue damage, and reduced growth rates. Protozoans like Haemogregarina species parasitize erythrocytes, leading to hemolytic anemia, while trypanosomes (Trypanosoma spp.) affect the bloodstream. Leeches may occasionally attach externally in wild populations, potentially causing wounds and secondary infections in contaminated waters. Emerging challenges include antibiotic resistance in cultured populations, where bacterial isolates like Escherichia coli and Aeromonas spp. exhibit multidrug resistance to common treatments such as and , complicating disease management in . These health issues contribute to economic losses in and pose risks to wild populations through escaped infected individuals.

Natural predators

The eggs and hatchlings of the Chinese softshell turtle (Pelodiscus sinensis) are vulnerable to predation by birds such as and , as well as reptiles like monitor lizards in native Asian habitats, which dig up nests. Mammals including otters may also target nests and young turtles. Adult Chinese softshell turtles experience rarer predation due to their effective and defensive behaviors, but they can occasionally fall victim to large aquatic predators like , avian hunters such as eagles, and terrestrial mammals including foxes and feral dogs. These encounters are infrequent, as adults inhabit muddy substrates that provide natural cover for concealment. To counter these threats, Chinese softshell turtles employ several anti-predator strategies across life stages. They rapidly bury themselves in mud or sand for , retracting their tubular snorkel-like to remain hidden while breathing through small openings. When directly threatened, individuals display aggressive behavior, including lunging bites capable of inflicting serious injury. These adaptations, combined with their flattened, leathery shell, enhance survival in predator-rich freshwater environments.

Conservation

Status and threats

The Chinese softshell turtle (Pelodiscus sinensis) is classified as Vulnerable on the (as of 2025), a status assigned in 2000 by the Asian Turtle Trade Working Group; the assessment requires updating due to an estimated population decline exceeding 30% over three generations resulting from ongoing anthropogenic pressures. This decline is inferred from observed reductions in wild densities across its native range in , particularly in riverine and lacustrine habitats, where mature individuals face intensified exploitation and . Habitat loss represents a primary threat, driven by dam construction, river channelization, and that fragment and degrade essential freshwater ecosystems. Overcollection for commercial trade exacerbates this vulnerability, with wild populations heavily targeted despite extensive ; the trade volume is met largely by farming, but continued unsustainable harvesting of wild individuals occurs due to preferences for wild-caught specimens that command premium prices. Pollution further compounds these risks, as like and pesticides accumulate in the turtles' tissues through their aquatic diet and permeable skin, causing physiological stress, reduced reproduction, and increased mortality. studies indicate elevated levels of such contaminants in P. sinensis from polluted rivers, impairing immune function and overall fitness. poses an emerging threat to freshwater turtle habitats by altering environmental conditions. Diseases, including bacterial and viral infections, can exacerbate these declines by increasing mortality in weakened populations exposed to polluted or fragmented environments.

Conservation measures

The Chinese softshell turtle (Pelodiscus sinensis) is classified as a Class II nationally protected wild animal under China's Wildlife Protection Law, prohibiting unauthorized capture, , and of wild individuals to safeguard declining populations. This legal framework supports broader aquatic regulations, emphasizing sustainable practices amid threats like habitat degradation. It is also listed on Appendix II, which regulates to prevent . Captive breeding programs in have achieved large-scale success, with annual production surpassing 300,000 tons since 2011, primarily to fulfill commercial demand while alleviating pressure on wild stocks. These efforts include government-backed farms and reserves that propagate individuals for potential release to bolster natural populations; however, post-release tracking remains limited, hindering evaluation of long-term viability. restoration efforts focus on preservation in core ranges like the Yellow River Delta, where rehydration projects aim to maintain suitable and foraging sites critical for overwintering adults. Monitoring integrates radio for tracking movements and genetic analyses to assess population structure and diversity, informing targeted interventions such as site-specific protections against seasonal flooding alterations. These measures collectively prioritize wild population recovery while leveraging to mitigate .

Human relations

Culinary and medicinal uses

The Chinese softshell turtle (Pelodiscus sinensis) is highly valued in for its tender, mild-flavored , often compared to in texture, with a surrounding layer of gelatinous that enhances dishes. It is commonly prepared as or , as well as clear stew, braised dishes, or medicinal soups, using fresh live turtles to retain maximum nutrients. Simmered with herbs and spices, these preparations create rich, nourishing broths that incorporate the , , and innards for a no-waste approach. These dishes are staples in and southern Chinese cooking, where the turtle is consumed fresh to preserve its delicate qualities, though dried is also used in some preserved forms. In (TCM), the 's shell, known as biejia or carapax, is a key ingredient prized for its ability to clear heat, nourish yin, and soften hard masses or accumulations, making it a component in formulas like Biejiajian pills traditionally used to treat conditions such as . The turtle's blood is employed in tonics and wines believed to invigorate energy, replenish vital proteins, and promote overall vitality, often added to herbal mixtures for restorative purposes. Moderate consumption of the turtle is believed in TCM to benefit health by nourishing yin and promoting vitality, though caution is advised for pregnant women and individuals with spleen deficiency or weak stomach conditions. These medicinal applications stem from ancient texts describing the turtle as a health-strengthening agent capable of warding off diseases. The demand for both culinary and medicinal uses has driven extensive commercial farming in , with hundreds of millions of individuals produced annually to supply domestic markets. To safeguard declining wild populations, China has enforced export restrictions on wild softshell turtles since the late , including import bans on contaminated farmed stock in 1999 and broader trade regulations under national protection laws.

Cultural significance

In , the softshell turtle holds symbolic value as an emblem of and resilience, often depicted as a creature capable of enduring extreme conditions by burrowing into , reflecting its adaptive as a mud-dweller. This association stems from ancient beliefs attributing to it a lifespan exceeding 10,000 years, positioning it as a semi-mythical being that embodies auspicious progress, as it is said to "only climb forward, not backward." In , such as accounts from classical texts, the softshell turtle appears as the zhū biē yú, a pearl-spitting entity resembling dried meat with multiple eyes and legs, symbolizing the harmony of , , and Man, though its utility ironically led to its frequent exploitation. Traditional practices incorporate the softshell turtle into rituals tied to prosperity and health, particularly during the , where consuming middle-aged specimens is believed to invoke strength and longevity due to the animal's symbolic endurance. Certain taboos persist, such as prohibiting pregnant women from eating softshell turtles, viewed as a "cold" food that could harm the fetus, underscoring broader cultural cautions around its potent, yin-natured properties in . In contemporary representations, the Chinese softshell turtle serves as an emblem of ecosystems and environmental fragility in literature and media, highlighting threats to aquatic habitats amid rapid development. documentaries and conservation narratives often feature it to underscore in China's rivers and lakes, reinforcing its role as a of under duress.

Aquaculture and invasive potential

The Chinese softshell turtle (Pelodiscus sinensis) is the dominant in global , with producing nearly all of the world's supply through intensive pond farming systems. Annual production in reached 497,536 metric tons in 2023. Farming practices originated over 2,400 years ago but intensified in the 1970s with the adoption of techniques, where turtles are co-reared with to optimize stocking densities, enhance resource utilization, and control waste through complementary feeding habits. However, recent challenges including , disease outbreaks, and shifting markets have led to declines in farming in some southern regions as of 2024. These systems typically involve or earthen ponds stocked at densities of 10–20 individuals per square meter, with supplemental feeding of commercial diets at 1–4% of body weight daily, achieving growth from juveniles (around 400–600 g) to market size (700–1,800 g) in 5–12 months. Yields in setups, including rice-turtle or -turtle combinations, commonly range from 1–3 tons per after one to four years, with survival rates of 89–96% and feed conversion ratios of 2.6–3.1. Beyond its native range in , P. sinensis has been introduced to regions like the and primarily through the pet and food trades, posing risks as an due to its adaptability and predatory behavior. In the contiguous U.S., the species exhibits a high climate match (score of 0.347), indicating suitable conditions for establishment, while it is already reproducing in (e.g., on Oahu and Kauai), where it competes with native aquatic and for resources and may alter local food webs. European assessments classify P. sinensis as having moderate establishment potential (risk score of 0.32), with isolated records in countries like the and potential to outcompete native freshwater turtles such as Emys orbicularis for basking sites, foraging areas, and nesting habitats in warmer wetlands. Although direct hybridization with native softshell turtles like Apalone spinifera remains undocumented, the species' broad environmental tolerance heightens concerns for genetic in overlapping habitats. Management of non-native P. sinensis populations focuses on prevention through trade regulations and public education, as eradication efforts are rare due to the species' cryptic nature and limited documented impacts. In the U.S., importation to has been banned since 1999 to curb further spread, with ongoing surveys recommended to monitor populations and assess ecological effects before targeted removals. Regulation 1143/2014 lists invasive alien species and mandates risk assessments, prohibiting releases of pets like P. sinensis while emphasizing early detection and rapid response in affected wetlands. These measures aim to mitigate invasion risks from pet trade releases, though enforcement challenges persist in both regions.

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