Announced dead: There may be only two Yangtze giant softshell turtles left on Earth

According to Vietnamese media reports, on April 24, relevant Vietnamese authorities confirmed that a Yangtze giant softshell turtle in Dong Mo Lake had died last Sunday. This means that there may only be two Yangtze giant softshell turtles left on Earth .

The Yangtze giant softshell turtle was 1.56 meters long and weighed 93 kilograms. The cause of death is currently unknown and is still under investigation. It was sampled and marked in 2020 and released into the lake, which means that it is likely the only female Yangtze giant softshell turtle previously confirmed . Its death has closed another door to the already slim hope of rescuing the Yangtze giant softshell turtle.

Yangtze giant softshell turtle | e.vnexpress.net

The Yangtze giant softshell turtle disappears from rivers

The Yangtze giant softshell turtle (Rafetus swinhoei), commonly known as the "癞头缋[yuán] ", is the largest extant turtle . The carapace of an adult is over 1 meter long and weighs over 100 kilograms. Its body is covered with fine yellow stripes, among which the pattern on its head is the most colorful and eye-catching.

Close-up of the head of a giant softshell turtle | WCS

According to the unearthed remains and ancient classics, the giant softshell turtle was once widely distributed in many water systems such as the Huaihe River, the Yellow River, the Yangtze River, and the Red River . The ancients often used its meat as a source of food . The Taihu Beikao compiled during the Qianlong period of the Qing Dynasty recorded that "it was a delicacy in ancient times. It can be found in Taihu Lake today, but it is not easy to obtain." The skeletons of the giant softshell turtle have also been unearthed in ash pits at many ancient human activity sites, indicating that in the past, the giant softshell turtle was a large turtle with a wide distribution and large number .

In modern times, the population of Yangtze giant softshell turtles has shrunk rapidly due to habitat loss and human hunting . In the past 100 years, the Yangtze giant softshell turtle has disappeared in the lower reaches of the Yangtze River and the Taihu Lake Basin, and the population in the Red River Basin and the Majiang River Basin has shrunk rapidly. Currently, the only known natural habitats of the Yangtze giant softshell turtle are two lakes in northern Vietnam. Before the death of this turtle, there were only three wild Yangtze giant softshell turtles in the world , including two in Dong Mo Lake (but one of them is not sure whether it exists) and one in Xuan Khanh Lake. Another old male turtle is kept in captivity in Suzhou Zoo, China.

Male Yangtze giant softshell turtle at Suzhou Zoo | Qi Shuo

A tortuous rescue

In the past, the Yangtze giant softshell turtle was often confused with the cantorii . Whether it was the confusion in name or the change in classification status, it directly affected the basic research of the Yangtze giant softshell turtle and the cantorii, and caused many difficulties for the subsequent protection work. By the time people faced this problem, the Yangtze giant softshell turtle had already missed the best time to protect it.

Turtle | Brown R et. al. / ZooKeys (2013)

The rescue plan for the Yangtze giant softshell turtle was not started until the beginning of the 21st century. From 2006 to 2008, the protection process of the Yangtze giant softshell turtle was full of twists and turns. The ancient Yangtze giant softshell turtle population was in turmoil, which concerned countless people.

September 2006

The "Southern Softshell Turtle Conservation Cooperation and Exchange Seminar" jointly organized by multiple departments was held in Suzhou. At that time, there were only five confirmed surviving individuals of the Yangtze River Softshell Turtle in the world .

Among them, there is one in Suzhou Zoo ("Su Su"), two in Suzhou Xiyuan Temple ("Yuan Yuan" and "Fang Fang", the female Yuan Yuan has not been seen for many years), one in Shanghai Zoo, and one in Hoan Kiem Lake, Vietnam.

December 2006

Bad news came from the Shanghai Zoo. The only female Yangtze giant softshell turtle known at the time was declared dead, and the protection of the Yangtze giant softshell turtle was once again at a stalemate.

January 2007

A female soft-shell turtle named Xiangxiang in the Changsha Zoo in Hunan Province was re-identified as a Yangtze giant soft-shell turtle. More gratifyingly, Xiangxiang is in excellent health and lays a batch of unfertilized soft-shell turtle eggs every year, which undoubtedly gives many researchers great confidence.

August 2007

With the news of the death of Fang Fang, a male Yangtze giant softshell turtle in Xiyuan Temple in Suzhou, the number of Yangtze giant softshell turtles in the country has once again dropped to two. This male and female have become the only hope to save the species.

2008

With the coordinated efforts of the Turtle Survival Alliance, the International Wildlife Conservation Society and other parties, Xiangxiang from Changsha Zoo embarked on the journey of marrying off to Suzhou in 2008. Waiting for her was the elderly male "Susu" who had lived alone for decades .

At the same time, the Dong Mo Reservoir, about 60 kilometers west of Hanoi, Vietnam, collapsed and an adult Yangtze giant softshell turtle floated downstream and was caught by fishermen. Upon hearing the news, researchers released it into the reserve and formulated a strict protection plan.

Photographed at Suzhou Zoo | Qi Shuo

The story seems to be finally developing in a positive direction.

However, although the couple had mated and laid eggs in their first year of marriage, unfortunately none of the more than 100 eggs were fertilized. Although fertilized eggs were laid after multiple attempts the following year, the embryos inside the eggs all died in the early stages of development . It is speculated that insufficient calcium intake by the female and low sperm motility in the male may be the main reasons for the failure of breeding.

In desperation, the international expert group finally launched the artificial insemination plan for Yangtze giant softshell turtles in 2015, but until the last sperm collection and insemination on April 12, 2019, the couple of Yangtze giant softshell turtles in Suzhou Zoo did not leave any offspring. During this artificial insemination process, the female "Xiangxiang" died, and the artificial breeding plan of Yangtze giant softshell turtles that lasted for more than ten years failed.

A pair of giant softshell turtles at Suzhou Zoo was expected to help save the species, but it never came true | Qi Shuo

The only hope

After China's captive breeding program failed, the only hope for saving the species fell to Vietnam .

In 2016, the well-known elderly Yangtze giant softshell turtle "Turtle Ancestor" in Vietnam's Hoan Kiem Lake died; in 2018, scholars used environmental DNA technology to believe that there was also a wild Yangtze giant softshell turtle in Xuanhan Lake.

In 2020, conservation workers captured a wild Yangtze giant softshell turtle in Tongmo Lake, where the Yangtze giant softshell turtle had been confirmed to exist. After a careful physical examination and sampling, it was sent back to the lake. The good news is that this is a female Yangtze giant softshell turtle with a dorsal disc length of 99.5 cm and a weight of 86 kg. The bright yellow markings on the head and neck indicate that it is in its prime. This is the only living female Yangtze giant softshell turtle in the world since the death of the female Yangtze giant softshell turtle in Suzhou Zoo .

In addition, Vietnamese researchers also claimed that there is another larger wild turtle living in Dong Mo Lake. They plan to capture this turtle to determine its gender, and if it happens to be a male, they will try to induce the two turtles in the same lake to mate.

A Yangtze giant softshell turtle captured in Dong Mo Lake, Vietnam | Phuongcacanh / Wikimedia

However, more than two years have passed, and we have not found any news about this unidentified turtle, and we cannot be sure whether it really exists. Then came the latest bad news - a turtle died in Tongmo Lake. From the information that has been disclosed, this dead turtle is likely to be the only female.

The hope of saving the Yangtze giant softshell turtle seems even slimmer. Can these legendary species with long lifespans still wait for new miracles?

Author: Qi Shuo

Editor: Calendar Girl, Mai Mai

Cover image source: WCS