The Yangtze giant softshell turtle, believed to be above 90 years of age, died in Suzhou Zoo on Saturday, according to the Suzhou Daily.

Its death came a day after zoo officials made a last-ditch effort at artificial insemination using semen from a male companion estimated to be more than 100 years old, according to the Suzhou Daily.

The zoo tried unsuccessfully for several years to get the pair to mate and reproduce naturally. It will now conduct an autopsy to determine what caused the animal's death, the newspaper reported.

Conservations say there are now only two other known members of the species left, both living in the wild in Vietnam and of unknown gender.

The Yangtze giant softshell turtle is the largest freshwater turtle in the world, growing to 100 cm (39 inches) long and weighing up to 100kg (220 pounds).

The turtle's main habitat was the Yangtze River and other inland China waterways.

But aquatic life in China's rivers has suffered severely from centuries of hunting and, more recently, decades of pollution, shipping traffic and ecological disruption wrought by hydroelectric dams.