The kha-nyou was discovered by scientists visiting a market in Lao PDR in 2005. It was subsequently shown to be a living fossil – the sole surviving member of an ancient group of rodents that was previously considered to have gone extinct some 11 million years ago. The kha-nyou is extremely distinct from all other mammal species, having separated from its closest living relatives, the gundis of Africa, 44 million years ago. It resembles a cross between a squirrel and a large rat, with its elongated head, small, rounded ears and bushy tail. Known only from an area of limestone karst in Khammouan Province in Lao PDR, the species is thought to be under pressure from hunting practices and possibly habitat degradation resulting from logging and the collection of firewood.