One of the world’s rarest turtles, a Yangtze giant softshell, has died in a Chinese zoo, leaving only three of the critically endangered species left.

The turtle was the last confirmed female in the world when she died during fertility treatment, raising the grim prospect that the species, which is also known as the Red River giant and is native to China and Vietnam, may now be functionally extinct.

The female had been over 90 years old when she died on Saturday in the Suzhou zoo in southern China after a round of artificial insemination, the fifth since 2008.

She was moved to Suzhou from the Changsa Ecological Zoo 11 years ago to be paired with the male turtle there.

The male Yangtze giant softshell, now over 100, is still housed at the zoo but the other two remaining creatures are living in the wild in Vietnam and their gender is unknown.

The species, which may be the largest freshwater turtle in the world and which is known for its pig-like snout, has been all but wiped out by hunting, overfishing and the destruction of its habitat.

China’s state-run People’s Daily reported that the female turtle had been in good medical condition before the fertility procedure and that it had appeared to go well until she unexpectedly died the next day.