Yangtze giant softshell turtle
|Yangtze giant softshell turtle|
|R. swinhoei of Dong Mo, Son Tay, Vietnam|
The Yangtze giant softshell turtle (Rafetus swinhoei) also known as the Red River giant softshell turtle, Shanghai softshell turtle, Swinhoe’s softshell turtle or speckled softshell turtle (Chinese: 斑鱉; Pinyin: bān bīe) is an extremely rare species of softshell turtle found in Vietnam and China. Only four living individuals are known, two in China (captive) and two in Vietnam (wild), (a fifth from Vietnam having been reported dead in January 2016), and it is listed as critically endangered in the IUCN Red List. It may be the largest living freshwater turtle in the world. It is hoped that a pair at Suzhou Zoo in China will breed.
The Yangtze giant softshell turtle is noted for its deep head with a pig-like snout and dorsally placed eyes. This critically endangered species holds the title of being the largest freshwater turtle in the world. Although hard to compare due to the extremely small number of remaining specimens, its average and maximum sizes seem to exceed other large freshwater turtles such as 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 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. The last known specimen caught in the wild in China was in 1998 in the Red River between Yuanyang and Jianshui; it was then released. Only four living specimens are known, one at Dong Mo Lake Son Tay in Hanoi, Vietnam, (taxonomy questioned), one at Xuan Khanh Lake near Hanoi, Vietnam, and two in Suzhou zoo in 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 trash and pollution in the lake or injuries from fishing hooks or other turtles) that needed to be treated. It was reported dead in January 2016.
Ecology and behaviour
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 Changsha Zoo was introduced to the only known male in China, a 100-year-old individual in Suzhou Zoo, in 2008. The female, who is over 80 years old, was said to settle in well after her 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 were fertile.
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.
Relationship with humans
Scientific description and systematics
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.
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 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[when?] 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.
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 unfortunately 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 turtle are now being 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. The female should lay the eggs a few weeks after and fertility of the eggs can be determined a couple weeks after laying. As of late July, the female had laid 2 clutches of eggs, totaling 89 eggs, but none were viable.
As of mid-2017, conservationists are searching for any possible wild individuals in the remote parts of China. A major target of the survey are parts of the Red River in Yunnan Province. Locals in the area have reported seeing 1-2 turtles that have a similar description to that of this species, meaning that there is a small possibility the species may still survive in the wild.
In April 2018, conservationists confirmed the existence of a fourth wild individual in Xuan Kanh Lake, Vietnam. The individual was photographed two times in 2012 and 2017, but both times the photograph was blurry and provided little confirmation of its identity. Using traces of the turtle's DNA in the lake's water, the specimen's identity was confirmed as R. swinhoei.
The legend of Kim Qui
The specimen (which may be a distinct species R. leloii) located in Hoan Kiem Lake, in Hanoi is thought to be the legendary Kim Qui (金龜), or Golden Turtle God, who has appeared at opportune moments throughout Vietnamese history. The golden turtle first appeared during the reign of King An Dương Vương (257-207 BC) and assisted the king in the construction of defenses for the ancient capital of Co Loa. When Co Loa was attacked, Kim Qui assisted the king in making a magical cross-bow that massively rained arrows upon the invaders in only a single shot. When the King's daughter conspired against her father, Kim Qui emerged again to inform An Duong Vuong of the betrayal; the king consequently killed his daughter and drowned himself in the sea.
In the 15th century, a gentry named Lê Lợi obtained a magical sword named Heaven's Will that a fisherman had pulled out of the lake. Lê Lợi used this sword to lead a rebellion against the Chinese armies that were in occupation of Vietnam. After overthrowing the Chinese rule and establishing the Lê Dynasty, the now-emperor Lê Lợi returned to the lake and Kim Qui emerged, then asked Lê Lợi to return the sword. The King drew the sword and hurled it toward Kim Qui. Kim Qui quickly caught the sword by his teeth, then submerged. Lê Lợi afterwards named the lake 'Lake of Returning Sword', or Hoan Kiem.
- Asian Turtle Trade Working Group (2000). "Rafetus swinhoei". The IUCN Red List of Threatened Species. IUCN. 2000: e.T39621A97401328. doi:10.2305/IUCN.UK.2000.RLTS.T39621A10252043.en. Retrieved 13 January 2018.
- Fritz, Uwe; Havaš, Peter (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 321–322. ISSN 1864-5755. Archived from the original (PDF) on 2010-12-17. Retrieved 29 May 2012.
- "Almost Extinct Turtle Discovered Living In Wild In Northern Vietnam". ScienceDaily. Retrieved 2014-06-16.
- Dudgeon, D. (2010). Requiem for a river: extinctions, climate change and the last of the Yangtze. Aquatic Conservation: Marine and Freshwater Ecosystems, 20(2), 127-131.
- "World's Largest Freshwater Turtle Nearly Extinct". National Geographic. 2013-07-01. Retrieved 2014-07-22.
- Jian, W., Hai-Tao, S., Cheng, W., & Lian-Xian, H. (2013). Habitat Selection and Conservation Suggestions for the Yangtze Giant Softshell Turtle (Rafetus swinhoei) in the Upper Red River, China. Chelonian Conservation and Biology, 12(1), 177-184.
- Le D. M. and Pritchard P. (2009), Genetic variability of the critically endangered softshell turtle, Rafetus swinhoei: a preliminary report, in: Ngo D. C., Ta H. T., Le N. N., Hoang X. Q., Vo V. P., Nguyen V. S., Nguyen V. T., Le T. T., and Tran Q. D. (eds.), Proc. of the 1st Natl. Sci. Workshop on Amphibians and Reptiles in Vietnam, Hue Univ. Press, Hue, pp. 84 – 92.
- Farkas, Balázs; Minh Duc Le; Truong Quang Nguyen (2011). "Rafetus vietnamensis Le, Le, Tran, Phan, Phan, Tran, Pham, Nguyen, Nong, Phan, Dinh, Truong and Ha, 2010 – another invalid name for an invalid species of softshell turtle (Reptilia: Testudines: Trionychidae)". Russian Journal of Herpetology. 18 (1): 65–72. Retrieved 17 February 2012.
- Farkas, B.; Webb, R.G. (2003). "Rafetus leloii Hà Dinh Dúc, 2000—an invalid species of softshell turtle from Hoan Kiem Lake, Hanoi, Vietnam (Reptilia, Testudines, Trionychidae)". Zoologische Abhandlungen. 53: 107–112.
- "Species: Rafetus swinhoei". Asian Turtle Conservation Network. Archived from the original on 2006-12-14. Retrieved 2006-12-09.
- "Draft Action Plan- Rafetus swinhoei" (PDF). Turtle Survival Alliance. Archived from the original (PDF) on June 21, 2007. Retrieved 2006-12-09.
- "Hoan Kiem Lake Turtle: from myth to reality". VietNamNet Bridge. 2005. Archived from the original on 2006-12-07. Retrieved 2006-12-09.
- "Vietnam hauls in beloved turtle for medical treatment". BBC. 2011-04-03. Retrieved 2011-04-03.
- Cu Rua: Vietnam mourns revered Hanoi turtle, BBC News, 20 January 2016
- "Relocation of endangered Chinese turtle may save species". Newswise. Retrieved on June 30, 2008.
- "World's Largest Freshwater Turtle Nearly Extinct". News.nationalgeographic.com. 2013-07-01. Retrieved 2014-06-16.
- "New individual of world's rarest turtle found in Hanoi". Retrieved 2018-04-16.
- Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Rafetus swinhoei, p.p. 258-259).
- Gray, J. E. (1873), "Notes on Chinese Mud-Tortoises (Trionychidae), with the Description of a new Species sent to the British Museum by Mr. Swinhoe, and Observations on the Male Organ of this Family", Annals and Magazine of Natural History, series 4, vol. XII, 1873. Pp. 156-161, and plate V.
- "Rafetus swinhoei" in: UWE FRITZ and PETER HAVAŠ, Checklist of Chelonians of the World Archived 2011-06-23 at the Wayback Machine., p. 182.
- Le, Tran Binh. "COMPARATIVE MORPHOLOGICAL AND DNA ANALYSIS OF SPECIMENS OF GIANT FRESHWATER SOFT-SHELLED TURTLE IN VIETNAM RELATED TO HOAN KIEM TURTLE" (PDF). Retrieved 17 February 2012.
- "红河干流梯级综合规划报告通过评审". Yunnan Channel, Xinhua Net. 2003-04-04. Archived from the original on 2009-02-12. Retrieved 2008-09-10.
- "Workshop on Rafetus Conservation in the Honghe (Red River) Drainage Area". Asian Turtle News. 2008-05-30. Retrieved 2008-09-10.
- Moore, Malcolm (2008-10-06). "Bid to save world's rarest turtles fails". The Daily Telegraph. London. Retrieved 2010-05-22.
-  NY Times, retrieved on October 9, 2008.
- "World's Last Yangtze Turtle Pair Fails to Reproduce, Again". EcoWorldly. 2009-10-15. Retrieved 2009-12-03.
- Artificial insemination New York Times, Retrieved May 25. 2015
- "First Artificial Breeding Attempt for World's Rarest Turtle Unsuccessful". 2015-07-22.
- "There Are Only 3 of These Turtles Left on Earth". 2017-05-23. Retrieved 2017-06-02.
- "Population of world's rarest giant turtle rises to 4 with new discovery". news.mongabay.com. Retrieved 2018-04-16.
- Meylan, P.A. Rafetus swinhoei. in Pritchard, P.C.H., and A. Rhodin eds., The conservation biology of freshwater turtles. IUCN publications.
- Meylan, P. A. and R. G. Webb. 1988. Rafetus swinhoei (Gray) 1873, a valid species of living soft-shelled turtle (family Trionychidae) from China. Journal of Herpetology. 22:118-119.
|Wikispecies has information related to Rafetus swinhoei|
|Wikimedia Commons has media related to Rafetus swinhoei.|
- China's Turtles, Emblems of a Crisis - The New York Times
- Species: Rafetus swinhoei - Asian Turtle Conservation Network
- Video:The Loneliest Animals - The Last Living Pair of Rafetus Turtles - PBS
- Rafetus swinhoei IUCN Red List of Threatened Species
- In Search of Rafetus swinhoei - Turtle Conservation Vietnam
- It's love or bust for Yangtze turtles - The Observer
- Picture th:ภาพ:Rafetus thanh hoar.jpg