One of the planet's last remaining Amur leopards, a 20-year-old giant cat plagued by kidney disease and extreme old age, was euthanized at the Oregon Zoo, officials said on Wednesday.

"Given that there are fewer than 300 of these animals left in the world, every passing feels particularly poignant," zoo curator Amy Cutting said in a statement.

Before her death on Tuesday, Kia may have been the oldest of her subspecies on the planet, the zoo said. She gave birth to nine cubs, or 3 percent of the world population of Amur leopards, over her lifetime.

"She had a good life, raised a bunch of cubs and was an excellent mother," said Cynthia Kreider, who leads the Association of Zoos and Aquariums' efforts to boost and preserve Amur leopards in the wild.

Populations of the giant cat, which are only found in northern China and Russia's far east, have been decimated by poaching, inbreeding and fires, with fewer than 70 of the animals believed to live in the wild.

Kia's cubs are now part of an effort to breed and preserve new generations of the animals, the zoo said.