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Yangtze Giant Softshell Turtle (Rafetus swinhoei)

Field Surveys for Wild Rafetus

RsF12Jun10SuzhouXThe known world population of Yangtze giant softshell turtles (Rafetus swinhoei) presently counts four living specimens: two in separate lakes in the northern part of Vietnam (Red River drainage) and two in China where the only confirmed female from Changsha Zoo is on breeding loan at Suzhou Zoo since 2008, paired with the only surviving male in China. The male at the Suzhou Zoo appears to be very old and, despite many mating interactions over the last years, none of the numerous eggs the female laid annually produced any hatchlings and all eggs of 2011 were infertile.

Several surveys for Rafetus swinhoei took place over recent years in Vietnam, Laos and China. One of the two specimens in Vietnam, probably a middle-aged adult male, was discovered during such a survey in Dong Mo Lake in the Red River drainage in 2007. A survey along the Red River in Yunnan conducted by Conservation International in February 2007 confirmed the historic occurrence of the species in the Red River in Yunnan and listed several individuals which were recorded up to 1998, but could not find firm evidence for more recent captures or sightings.

The TSA funded a fact-finding mission to the Red River in Yunnan in September 2011 to confirm the information and data reported in 2007. Unfortunately, the team (led by Dr. Gerald Kuchling) also did not find evidence of recent sightings of the species. The main goal of their mission was to visit all Forestry Bureaus in Yunnan where Rafetus had been reported in the past to find out about past and current attempts to collect data on the species. They discovered that all Forestry Bureaus were aware of the rare and threatened status and the significance of the species and are monitoring the respective markets where softshell turtles are traded with the aim to rescue any Rafetus which might be offered for sale.

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Rafetus Breeding Attempt 2011

RsM30May11XWith the glass barriers around both ponds at Suzhou Zoo having been completed in the summer of 2010, the male and the female Yangtze giant softshell turtle (Rafetus swinhoei) have roamed together in both the small and the large pond since 24 August 2010. For the first time, the male and the female were together throughout fall, winter and spring. Following hibernation, the male and the female became active on 25 March 2011 when they both were seen basking. Abrasions on the neck and front limbs of the female when she emerged from hibernation indicated mating attempts during fall/winter (the male grabs the neck of the female with his jaws prior to mounting). The turtles' diet in 2011 consisted of pieces of fresh fish with skin and bones, whole freshwater crayfish, freshwater snails, sausages filled with a mixture of fresh, high quality minced fish, freshwater crayfish, prawns, egg shells, vitamin and calcium supplements, and chicken heads and wings. The sausages are readily eaten by both the female and the male, ensuring good nutrition.

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Rafetus Season Ends in Disappointment

RsF12Jun10SuzhouXThe fourth season for the Rafetus breeding project has come to an end, without the results that we were all hoping for.  It seems that out of the 188 eggs laid, none were actually fertilized.  This has put all of us on the project in a bit of a predicament wondering how to proceed next year (note I said how not if.  There is no question in any of our minds that the project will continue, so long as we have these individuals and if there’s the possibility of other individuals out in the wild).

Depsite the fact that we didn’t get any Rafetus hatchlings, progress was still made and questions were answered.  Concerns about the efficacy of the incubators and incubation methods were put to rest when we successfully hatched more than a dozen red-eared sliders under various incubation conditions.  We also obtained 54 Chinese softshell (Pelodiscus sinensis) hatchlings from a local farm to rear in our large breeding tank.  By doing so, the zoo staff were able to learn how to care for softshells and try different feeding regimens to determine what works best.

RsSausagePrep11Aug10xThere were new challenges to be faced this year as well.  While stray cats and weasels are a known problem at the zoo, this was the first year we saw the weasels enter the Rafetus enclosure.  I was quite concerned because they could pose a threat to the eggs and potential hatchlings.  We therefore reinforced the fencing placed around each nest (standard protocol to keep out any unwanted visitors) and that seemed to solve the weasel problem.  Although they were still entering the enclosure, they could not get at the nests or the eggs. 

Even though we try to cover all our bases, there are always things that we cannot predict and subsequently prepare for.  Towards the end of August, Suzhou experience several severe thunder and lightning storms.  No one (human or animal) was hurt but the closed-circuit camera system we had installed was ruined.  The installation company has taken all the cameras and computer back to their factory to determine the extent of the damage and we are currently awaiting their final report before we can decide if the entire system needs to be replaced or if we just need to replace some of the parts. 

Soon, all of the collaborators on the project will meet again to wrap up this season and discuss options for next year.  Despite all the setbacks we’ve faced to date, all are hopeful that the “Year of the Rafetus” will be just around the corner.

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Turtle Behavior - More Than Just Basking

male_on_beachWhen people ask me what I do on day to day basis, they’re often surprised to hear that a lot of it is purely observational. I am by the turtle enclosures making notes on their behaviors. The general response is always “How active can turtles be?” But I think the truth will surprise many.

A good understanding of animal behavior is an important part of any conservation program. By watching them on a daily basis under various conditions, I can get a sense of what’s normal and what isn’t. Sometimes behavioral changes can signal a change in the overall health of the animal. For example, both animals will come out of brumation around March or April and many people assume they are ravenous at this time and will want to eat constantly. The male does eat fairly regularly early on in the summer but will go off his food later on, when the ambient temperatures get really high. The female is the opposite and doesn’t begin seriously eating until after she’s laid a few clutches of eggs and it’s warmer out (around mid-July). If this were to suddenly change, i.e. the male doesn’t eat early in the season or eats during the periods of extreme heat, it may be a warning sign that something else going on.

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Gearing up for Rafetus 2011

Editor's Note: With both the male and female Rafetus up and basking, the 2011 breeding season is upon us and all those involved are gearing up for this year’s work. Emily King will be based at the Suzhou Zoo throughout the breeding season and will be providing blog updates on this critical conservaton breeding project. 
Emily06Jun10SuzhouHi! I’m Emily and I’ve been lucky enough to have worked with the Yangtze giant softshell turtles at the Suzhou Zoo since the female was introduced to the male back in 2008.  For me, there was never any doubt in my mind what I wanted to do when I grew up. I wanted to work with animals, specifically with wildlife or exotic species.  But it wasn’t until I graduated from university that I discovered what so many people already knew – that turtles are COOL.

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Turtles In Trouble

coverClick here  for a PDF version of the full report.

The plight of the planet's tortoises and turtles -- creatures that have roamed the Earth for 220 million years -- has never been greater, according to the newly released report "Turtles in Trouble: Top 25+ Endangered Tortoises and Freshwater Turtles ."  It shows the world's 25 most endangered tortoises and freshwater turtles will become extinct in the next few decades without concerted conservation efforts.

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World's Rarest Eggs Fail to Develop

rafetus_nestingThe female Rafetus nested this year during the night of June 16 (63 eggs), again during the night of July 2 (63 eggs), and laid a third clutch on July 17. All eggs of the first two clutches were numbered and about half of those eggs were artificially incubated (29, 31 and 33 degrees Celsius, various substrates), the other half was left in the nests constructed by the female. The third nest was not disturbed at all and the eggs were left in place, without being handled.

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Back in China - 2010

Dr. Gerald Kuchling recently sent in this update from the Suzhou Zoo in China, where he has returned to spearhead another breeding attempt for the Yangtze giant softshell turtle (Rafetus swinhoei):

A quick update from China: I and Guundie (note: Dr. Kuchling’s wife), Dr. Lu Shunqing (Wildlife Conservation Society) and Emily King (TSA) all arrived in Suzhou on 18 April. The female Rafetus became active for the first time this year also on 18 April 2010, the day we all arrived in Suzhou. The male had showed some activity since 19 March.

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Second breeding attempt for Rafetus swinhoei in China leads to cautious optimism

The epic move of the last Chinese female Yangtze giant softshell turtle (Rafetus swinhoei) from Changsha Zoo to the last Chinese male at the Suzhou Zoo in 2008 resulted in successful mating, producing two clutches totalling over one hundred eggs. Despite this success, unfortunately none of the eggs hatched. About half the eggs of the second clutch were not properly shelled and many cracked during laying. Nutritional deficencies of the long-term captive female – over 70 years in captivity - were most likely to blame for this setback, and apparently caused any fertilized eggs to die early during development.   Despite this disappointment, this event captured the attention of the global conservation community, and the remarkable story was featured in a PBS/Nature special called The Loneliest Animals that aired on April 19, 2009. Click here to view. 

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Close call for the world's last R. swinhoei in the wild

Torrential monsoon rains caused rivers to spill over their banks and brought water in lakes and reservoirs to capacity throughout northern Vietnam.  It was mid-November 2008 and Team Rafetus Vietnam had just completed a series of awareness activities in local communities surrounding Dong Mo Lake (located about 60 km west of Hanoi) where the world’s last known Rafetus swinhoei remains in the wild. 

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