Order : RODENTIA
Family : Diatomyidae (formerly assigned to Laonastidae)
Species : Laonastes aenigmamus

Head-Body Length : up to 29 cm
Tail Length : up to 16 cm
Weight : up to 420 grams

The Kha-nyou is the only living member of the Diatomyidae. Other genera of this rodent family are known only from the fossil record, the youngest species of which occurs in sediments dated as around 11 million years old (i.e. late Miocene). The name 'Kha-nyou' has no direct translation to English, and simply refers to this unique animal.

The presence of Laonastes aenigmamus in Khammouan Province, Laos, was discovered by western science in the 1990's, when specimens were first acquired. The species was formally described in 2005 by Jenkins et al, although its existence would have long been known to local people who hunt and consume these small rodents as bushmeat.

At a glance, Laonastes aenigmamus looks like a large species of ground-dwelling squirrel, with a large head which is shaped, for example, rather like that of the Shrew-faced Ground Squirrel. Its dorsal fur is greyish-black, with a strong silvery sheen or frosting, its ventral fur is silvery-grey and, like squirrels, it has a bushy tail.

They are docile and slow-moving animals, which walk with their hind feet splayed strongly outwards: this is probably an adaptation which allows for a firm grip on steep rock surfaces.

Kha-nyou appear to be restricted to areas of sparsely vegetated, karst limestone where suitable rock crevices and deeply-weathered limestone boulders provide shelter. IUCN (Duckworth, 2016) quote an elevation range of 150-850 metres.

The species appears to be fully nocturnal, and primarily vegetarian in habits. Bones of Laonastes aenigmamus have been found in owl pellets (Jenkins et al, 2005).

Laonastes aenigmamus broadly occurs in central Laos (Khammouan province and southern Bolikhamxai province), and west-central Vietnam (Quang Binh province).

It is possible that Laonastes represents a group of closely-related species, some with very limited geographical ranges (Nicolas et al, 2012)

Fig 1 : Typical adult example of Kha-nyou, with silvery-blackish fur. Photo thanks to Miroslav Bobek.

Fig 2 : Typical karst limestone habitat in central and northern Laos.

Fig 3: A pair of Kha-nyou for sale in a market in central Laos, where indiscriminate consumption of small mammals is an entrenched part of local culture. Photo thanks to Yong Ding Li.


References :

Duckworth, J.W. 2016. Laonastes aenigmamus. The IUCN Red List of Threatened Species 2016: e.T136474A22199035

Francis, C.M. 2019. A Field Guide to the Mammals of South-east Asia. Second Edition. New Holland. 416 pp.

Jenkins, P. D., Kilpatrick, C. W., Robinson, M. F. & Timmins, R. J. (2005). Morphological and molecular investigations of a new family, genus and species of rodent (Mammalia: Rodentia: Hystricognatha) from Lao PDR. Systematics and Biodiversity, 2(4), 419-454.

Nicolas, V., Herbreteau, V., Couloux, A., Keovichit, K., Douangboupha, B. & Hugot, J-P. (2012). A remarkable case of micro-endemism in Laonastes aenigmamus (Diatomyidae, Rodentia) revealed by nuclear and mitochondrial DNA sequence data. PLoS ONE 7(11): e48145.