| Yangtze giant softshell turtle | |
|---|---|
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| One of the twoR. swinhoei of Dong Mo,Son Tay, Vietnam | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Cryptodira |
| Family: | Trionychidae |
| Genus: | Rafetus |
| Species: | R. swinhoei |
| Binomial name | |
| Rafetus swinhoei (Gray, 1873) | |
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| Yangtze giant softshell turtle range | |
| Synonyms[3] | |
List
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TheYangtze giant softshell turtle (Rafetus swinhoei), also commonly known as theRed River giant softshell turtle, theShanghai softshell turtle, thespeckled softshell turtle, andSwinhoe's softshell turtle, is a critically endangeredspecies ofturtle in thefamilyTrionychidae. It is regarded as one of the largest living freshwater turtle species. Native to eastern and southernChina and northernVietnam, the species has a known population of only two or three individuals, and the absence of fertile females has rendered itfunctionally extinct.
TheYangtze giant softshell turtle is recognized for its deep head, pig-like snout, anddorsally positioned eyes. As a critically endangered species, it is widely regarded as the largest freshwater turtle in the world.[4] Although comparisons are limited due to the small number of known specimens, its average and maximum sizes surpass those of other large freshwater turtles, such as thealligator snapping turtle and related giant softshell species, including otherRafetus andPelochelys species.[5]
Adult specimens exceed 100 cm (39 in) in length and 70 cm (28 in) in width, with weights ranging from 70–100 kg (150–220 lb).[6] A study of large turtles from theYangtze River reported an average weight of 25 kg (55 lb), although not all specimens were definitively identified asRafetus.[7]
The turtle’scarapace (shell) typically measures over 50 cm (20 in), with the largest recorded at 86 cm (34 in) in straight length. Curved carapace lengths of up to 106 cm (42 in) have also been reported. Exceptional specimens, primarily fromVietnam, are believed to have weighed between 220 to 247.5 kg (485 to 546 lb).[8][9] The head measures over 20 cm (7.9 in) in length and 10 cm (3.9 in) in width.
Sexual dimorphism is present, with males generally smaller than females but possessing longer, more prominent tails.[10]
Currently, only two or three living individuals of theYangtze giant softshell turtle are known to exist: one in captivity inChina and one or two in the wild inVietnam.[11]
The species' decline has been marked by significant losses in recent years. A wild individual in Vietnam was reported dead in January 2016, and the last captive female at theSuzhou Zoo in China died in April 2019 following an artificial insemination attempt.[12][13]
In October 2020, a wild female was discovered inDong Mo Lake in Vietnam, giving conservationists renewed hope. However, this individual was found dead in early 2023, further diminishing the species' chances of survival.[14]
An additional individual is believed to have been sighted in the same area, though its exact status remains uncertain. The known surviving turtles are thought to include one at the Suzhou Zoo and potentially one in the nearbyXuan Khanh Lake.[15][16]
TheYangtze giant softshell turtle historically inhabited theYangtze River andLake Tai, located on the border ofJiangsu andZhejiang provinces in easternChina, as well as areas in southern China, includingGejiu,Yuanyang,Jianshui, andHonghe inYunnan Province.[17]
Two specimens captured from Gejiu in the 1970s were kept at theBeijing Zoo and theShanghai Zoo but died in 2005 and 2006, respectively.
InVietnam, the species has been observed inHoan Kiem Lake inHanoi on several occasions, including documented sightings in 1999, 2000, and 2005.[18] The turtle captured from the lake in April 2011, which was treated for open sores potentially caused by pollution, injuries from fishing hooks, or other turtles, was later found dead in January 2016.[19][20]
In recent years, individuals have been identified inDong Mo Lake andXuan Khanh Lake in Vietnam. A turtle discovered in Dong Mo Lake in 2020 was confirmed to be female, but it died in April 2023. Another individual of unspecified gender is thought to inhabit the same lake, while an additional turtle is believed to live in Xuan Khanh Lake.[11][15]
TheYangtze giant softshell turtle primarily feeds on a diet offish,crabs,snails,frogs, and aquatic vegetation such aswater hyacinths and "green rice leaves."[citation needed]
The species typically lays between 20 and 80 eggs per clutch, with nesting occurring at night or during the early morning.[10]
In an attempt to prevent extinction, a fertile female from theChangsha Zoo was transferred to theSuzhou Zoo in 2008 to breed with the only known male in captivity, a 100-year-old individual. The move, coordinated by theWildlife Conservation Society and theTurtle Survival Alliance, involved transporting the female over 1,000 km (600 miles).[21] Despite this effort, breeding attempts have largely failed. By 2013, six breeding seasons had produced 80 eggs, none of which were viable.[22]
Artificial insemination was first attempted in 2015. While the process successfully fertilized a female, the eggs laid during two clutches were not viable. This female died in April 2019 after a subsequent insemination attempt.[23][12][13]
Despite its large size and distinctive appearance, the Yangtze giant softshell turtle is highly elusive. It spends most of its time submerged in deep water and surfaces only briefly to breathe, which complicates efforts to observe or identify wild individuals.[24]
TheYangtze giant softshell turtle was first described in 1873 byJohn Edward Gray, a turtle expert at theBritish Museum, who named itOscaria swinhoei after English biologistRobert Swinhoe, who had sent a specimen fromShanghai. Gray described the species as "the most beautiful species of Trionychidae that has yet occurred."[25]
In 1880,Pierre Marie Heude, a Shanghai-basedJesuit missionary, obtained multiple specimens of the species from theHuangpu River andLake Tai. Believing the specimens exhibited significant variation, he described them as five distinct species:Yuen leprosus,Yuen maculatus,Yuen elegans,Yuen viridis, andYuen pallens. The genus nameYuen derives from the Chinese 鼋 (yuan), meaning "large turtle." Later, zoologists reclassified the species under different genera, includingTrionyx,Pelodiscus, andPelochelys. In 1987,Peter Andre Meylan placed the species under the genusRafetus.[26]
The taxonomic status of the closely relatedHoan Kiem turtle (Rafetus leloii) remains controversial. While most herpetologists considerR. leloii ajunior synonym ofRafetus swinhoei, some Vietnamese biologists, such asHa Dinh Duc and Le Tran Binh, argue that it is a distinct species based on genetic and morphological differences. Critics, including Farkaset al., have attributed these differences to age-related variation and noted that the genetic data used by Leet al. were not submitted toGenBank. They also criticized the violation ofICZN Code rules when renamingR. leloii asR. vietnamensis.[8]
TheYangtze giant softshell turtle faces numerous threats that have contributed to its critically endangered status.Habitat loss due to urbanization, pollution, and dam construction has drastically reduced its natural range. Illegal wildlife trade and a lack of robust legislation to regulate hunting and trafficking have further compounded the species' decline.[27]
The species has also suffered from overexploitation, as turtles are hunted for food, subsistence, and local consumption. Additionally, their carapaces and bones are used intraditional medicine, and their skulls are sometimes kept as trophies.[10]
A recent plan to construct a series of 12 hydropower dams along theRed River inChina poses a significant risk, as it would flood critical habitats and alter the ecosystem downstream in Vietnam.[28]
| External image | |
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 One individual in Suzhou Zoo, 2008.[29] |
Conservationists have focused on captive breeding as a primary strategy to save theYangtze giant softshell turtle. In 2008, the last known fertile female, housed at theChangsha Zoo, was transferred to theSuzhou Zoo to breed with the sole known male in captivity. Despite six breeding seasons and numerous eggs laid, no viable offspring were produced.[22]
In 2015, artificial insemination was attempted for the first time. Although the procedure successfully fertilized eggs, none hatched. The female died in April 2019 after another artificial insemination attempt.[12][13]
To improve future breeding outcomes, conservationists have focused on better habitat conditions and dietary adjustments to increase calcium levels, which are believed to influence egg viability.[30]
Wild population monitoringIn parallel with captive breeding, efforts to locate wild individuals have intensified. Surveys inVietnam's Dong Mo and Xuan Khanh Lakes have identified potential survivors, though their numbers remain critically low. Conservationists continue to explore other areas, such as theRed River inYunnan Province, for remaining specimens.[31]
Conservationists have undertaken extensive efforts to locate wildYangtze giant softshell turtles in the remote regions ofChina andVietnam. Key areas of focus include parts of theRed River inYunnan Province, where locals have reported sightings of large softshell turtles that match the species' description. However, these reports remain unconfirmed despite intensive surveys.[32]
In 2018, DNA analysis of water samples fromXuan Khanh Lake inVietnam confirmed the presence ofRafetus swinhoei, marking the identification of a second wild individual. Additional surveys inDong Mo Lake revealed the existence of two turtles, including one identified as a female in 2020. However, this female died in 2023, leaving the number of known surviving individuals critically low.[14][15]
Despite setbacks, local conservation teams, supported by international organizations, continue to monitor these lakes and interview local communities to gather more information about potential surviving individuals. Efforts are also underway to explore new areas of habitat that could support this species.[33]
In recent years, conservationists have confirmed the existence of several wild individuals of theYangtze giant softshell turtle inVietnam.
In 2018, DNA analysis of water samples fromXuan Khanh Lake verified the presence ofRafetus swinhoei, confirming a second wild individual. Previously, this turtle had been photographed in 2012 and 2017, but the images were too blurry to provide conclusive identification.[34]
In November 2018, surveys inDong Mo Lake revealed the existence of a second turtle alongside the individual already known to inhabit the area. The two turtles were first observed together during the summer of 2018, and further monitoring confirmed one of them was female. This marked the discovery of the first confirmed female since the death of the last captive female in 2019.[35]
Unfortunately, the female discovered in Dong Mo Lake died in early 2023 from unknown causes.[15]
In addition to these verified sightings, local fishermen inYunnan Province have reported observing large softshell turtles in reservoirs created by theMadushan Dam. However, extensive surveys conducted in 2016 and 2017 failed to locate any surviving individuals in these areas.[36]
Other anecdotal reports suggest that aRafetus swinhoei lived in a pond inLaos for over 45 years but disappeared after a monsoon in 2013. While promising, these accounts have yet to be substantiated.[37]
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TheYangtze giant softshell turtle has deep cultural significance in Vietnamese folklore, where it is associated with the legendary figureKim Qui, or theGolden Turtle God (金龜). Kim Qui is said to have appeared at pivotal moments in Vietnam's history, offering guidance and assistance to its rulers.
During the reign ofAn Dương Vương (257–207 BCE), Kim Qui reportedly aided the king in constructing defenses for the ancient capital ofCo Loa. According to legend, the Golden Turtle provided the king with a magical crossbow capable of firing arrows en masse to repel invaders. When An Dương Vương’s daughter betrayed him, Kim Qui warned the king of her treachery, leading to her execution and the king’s eventual suicide.[18]
In the 15th century, Kim Qui is said to have appeared toLê Lợi, a Vietnamese nobleman and later emperor. Lê Lợi received the magical swordHeaven's Will from a fisherman and used it to lead a rebellion against theChinese occupation. After defeating the invaders and establishing theLê dynasty, Lê Lợi returned the sword to Kim Qui atHoan Kiem Lake ("Lake of the Returned Sword"). According to legend, the Golden Turtle surfaced to claim the sword, catching it in its jaws before disappearing into the depths of the lake.[18]
This legend has cemented the Yangtze giant softshell turtle as a symbol of resilience and cultural heritage in Vietnam, linking it to themes of national unity and divine intervention.
