Rephrase this into lesser words: once upon a time widespread throughout the yangtze river network in china, but eventually fell victim to widespread pollution, development and hunting. the yangtze giant softshell turtle is the largest freshwater turtle in the world. only three specimens are known to exist in the world after a fourth one died in vietnam in january 2016 only one is female, meaning that the survival of the species rests entirely on her capacity to breed. however, she's 100 years old, and so far there's no sign of motherhood for the old turtle. scientists are working to improve conditions at the enclosure to improve the odds that a brood will survive.