Red river giant softshell turtle, Shanghai softshell turtle, Speckled softshell turtle, Swinhoe's softshell turtle
The Yangtze giant softshell turtle (Rafetus swinhoei ; simplified Chinese: 斑鳖; traditional Chinese: 斑鱉; pinyin: bānbiē ), also known as the Red River giant softshell turtle, the Shanghai softshell turtle, the speckled softshell turtle, and Swinhoe's softshell turtle, is an extremely rare species of turtle in the family Trionychidae. It may be the largest living freshwater turtle in the world. The species is endemic to eastern and southern China and northern Vietnam. Only two or three living individuals are known: one in China (captive) and one or two in Vietnam (wild). Following the deaths of a wild individual in Vietnam in January 2016 and a captive individual in China in 2019, the species is listed as critically endangered in the IUCN Red List. The female of the last breeding pair died at Suzhou Zoo in China in April 2019. A wild female was discovered in Vietnam on October 22, 2020, and another individual is believed to have been sighted in the same area.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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OviparousOviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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starts withThe species became known to Western science in 1873, when John Edward Gray, the turtle expert at the British Museum, described the specimen sent to him from Shanghai by English biologist Robert Swinhoe. He named the species Oscaria swinhoei, and described it as "the most beautiful species of Trionychidae that has yet occurred."
f="/alligator-snapping-turtle">alligator snapping turtles and related giant softshells such as other Rafetus and Pelochelys species. It measures over 100 cm (39 in) in overall length and to 70 cm (28 in) in width, and can easily weigh up to 70–100 kg (150–220 lb). The average size of large turtle specimens (i.e. turtles weighing over 10 kg (22 lb)) that could be collected in the Yangtze River per one study was 25 kg (55 lb), although not all specimens were definitively identified as Rafetus. Its carapace, or shell, can grow larger than 50 cm (20 in), with the largest shell that could be found having measured 86 cm (34 in) in length. However, along the curve carapace lengths of up to 106 cm (42 in) have been reported and it is possible for the largest specimens (largely reported in Vietnam) to have weighed up 220 to 247.5 kg (485 to 546 lb). Its head can measure over 20 cm (7.9 in) in length and 10 cm (3.9 in) in width. The male is generally smaller than the female and has a longer, larger tail.
The species became known to Western science in 1873, when John Edward Gray, the turtle expert at the British Museum, described the specimen sent to him from Shanghai by English biologist Robert Swinhoe. He named the species Oscaria swinhoei, and described it as "the most beautiful species of Trionychidae that has yet occurred."
In 1880, the Shanghai-based French Jesuit Pierre Marie Heude obtained several specimens of this turtle, from the Huangpu River (near Shanghai) and Lake Tai (near Suzhou). He thought them sufficiently different from each other to describe them as five distinct species: Yuen leprosus, Yuen maculatus, Yuen elegans, Yuen viridis, and Yuen pallens. The genus name, Yuen, presumably comes from the Chinese 鼋 (transcribed yüen in the Wade-Giles system, or yuan in the modern Hanyu Pinyin), which means a large turtle.
Later zoologists classified these turtles as belonging to the genera Trionyx, Pelodiscus, and Pelochelys ; in 1987, Meylan categorized this species under the genus Rafetus.
The placement of the related or conspecific Hoan Kiem turtle, Rafetus leloii, remains poorly known and controversial. Most herpetologists accept R. leloii is a junior synonym of the Yangtze giant softshell turtle, though some Vietnamese biologists, such as Ha Dinh Duc, who first described R. leloii, and Le Tran Binh, assert R. leloii to be distinct. Le points out genetic differences, as well as differences in morphology. However, Farkas et al. repeated their 2003 conclusion in 2011, attributing differences between specimens to age, and pointed out that the genetic sequences used were never sent to GenBank. They also criticized the fact that Le et al. violated ICZN Code by renaming the species from R. leloii to R. vietnamensis on the grounds of "appropriateness".
The Yangtze giant softshell turtle has been known to inhabit the Yangtze River and Lake Tai, situated on the border of Jiangsu and Zhejiang Provinces, in eastern China, and Gejiu, Yuanyang, Jianshui and Honghe in Yunnan Province in southern China.
A specimen at the Beijing Zoo died in 2005, and another one at the Shanghai Zoo died in 2006; both of them were caught at Gejiu in the 1970s. In 1999, 2000, and 2005, turtles re-emerged from Hoan Kiem Lake in Hanoi and were seen by a large audience and caught on film. Only a single turtle was believed to be left in the lake. In April 2011, it was captured because it had open sores (possibly due to refuse and pollution in the lake, injuries from fishing hooks or other turtles) that needed to be treated. It was reported dead in January 2016. On April 13, 2019, the only female turtle in Suzhou Zoo was reported dead shortly after the latest fertilization process. In 2020, another female was found in Vietnam's Dong Mo Lake, and it is believed that another individual is also living at the lake. They may also be still another individual in nearby Xuan Khanh Lake.
Despite its massive size and distinctive appearance, this species is extremely secretive and only rarely comes up to breathe, largely preferring to stay submerged deep underwater. This may be part of the reason why it is so difficult to positively identify and confirm wild sightings of this species.
R. swinhoei eats fish, crabs, snails, water hyacinth, frogs, and green rice leaves.
The Yangtze giant softshell turtle may lay from 20 to more than 80 eggs. It nests at night and during the morning.
A fertile female from the Changsha Zoo was introduced to the only known male in China, a 100-year-old individual in the Suzhou Zoo, in 2008. The female, who is over 80 years old, was said to settle in well after her 1000-kilometre (600-mile) move, and biologists were optimistic for breeding success. The move was coordinated by the Wildlife Conservation Society and the Turtle Survival Alliance. In July 2013 National Geographic reported that in the sixth breeding season for the Suzhou mating pair, 80 eggs have been laid, but none was fertile.
Conservation efforts are concentrated on breeding captive turtles in China and searching for live specimens in the wild. An agreement was made to transfer the only known remaining female specimen located at the Changsha Zoo to the Suzhou Zoo to breed with the male specimen there. Also, efforts are being made to improve conditions for breeding at both the Suzhou Zoo and Western Temple in Suzhou.A workshop on the Rafetus Conservation at Yunnan was held by CI-Shanshui. Local Chinese scientists are searching for the last existent individuals. The two specimens were able to produce two clutches of eggs, with over half of them being fertile, though all of them perished before hatching. The Turtle Survival Alliance released a statement saying, "A number of the eggs had very thin shells, suggesting that the diet of the animals prior to breeding was not optimal." The two turtles were prepared for another round of mating, while being fed a high-calcium diet in an effort to strengthen the eggs. Liu Jinde, the director of the zoo said, "We've worked very hard on this, We ought to succeed. The turtles are very healthy."
The scientists began preparing to mate the two once again in May 2009, which fell within this species' breeding season, but in the fall of 2009, the zoo announced that despite laying 188 eggs, the eggs were infertile and would not hatch. The Turtle Survival Alliance issued a statement explaining the infertility was due in part to the turtle's poor diet and the group expressed concern that the zoo's patrons had thrown trash into the turtle's enclosure that, if eaten, could endanger the health of the turtles. On June 15, 2010, the female laid a total of 63 eggs. Half of the eggs were left in the sand to incubate naturally, while the other half were moved to incubate at varying temperatures and humidities. Once again, they were infertile.
In 2015 artificial insemination was attempted, a first for this species. In May 2015, the female was successfully inseminated. Semen was extracted from the sedated male using electro-ejaculation. By late July, the female had laid 2 clutches of eggs, totaling 89 eggs, but none were viable. The female later died in April 2019 following another artificial insemination attempt.
The Yangtze giant softshell turtle is on the brink of extinction due to habitat loss, hunting for subsistence and local consumption, and the use of the carapace and bones in alternative medicine. Skulls are often kept as trophies. A recent plan to build hydropower cascade of 12 dams on the Red River in China may flood all of its habitat and change the ecosystem of lower Vietnam.
