Gilbert's potoroo or ngilkat (Potorous gilbertii) is Australia's most endangered marsupial, the rarest marsupial in the world, and one of the world's rarest critically endangered mammals, found in south-western Western Australia. It is a small nocturnal macropod that lives in small groups.

It was thought to be extinct for much of the 20th century, having not been spotted for around a century, until its rediscovery in 1994. The only naturally located population is found in Two Peoples Bay Nature Reserve in Western Australia, where they co-exist with quokkas (Setonix brachyurus), but in 2015 a bushfire destroyed 90% of their habitat. Small populations are being established at Bald Island, off Albany, and more recently on Middle Island, off Esperance, all on the southern coast of Western Australia. Numbers have increased in recent years, and as of December 2018 the entire population was estimated to comprise at least 100 individuals, with 10 on Middle Island, 70 on Bald Island, 20 at Waychinicup National Park and two at Two Peoples Bay (also known as the Mt Gardner population).

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