Laotian rock rat

The Laotian rock rat, also known as the kha-nyou or "rat-squirrel" is a captivating rodent species discovered in the Khammouan region of Laos. First described in 2005, this unique species was so distinct that it was initially placed in a new family named Laonastidae. However, subsequent research revealed it actually belongs to the ancient family Diatomyidae, thought to have been extinct for 11 million years. This remarkable revelation led to the classification of the Laotian rock rat as a "Lazarus species" a term applied to species that reappear after being presumed extinct.

This rodent is the sole member of the genus Laonastes and resembles a large, dark rat with a squirrel-like tail. Its skull features distinct characteristics that differentiate it from other living mammals. Genetic studies have linked Laonastes to African rodents such as blesmols and dassie rats.

The name Laonastes translates to "inhabitant of stone" highlighting its habitat around limestone rocks and its recent discovery in Laos. The species name aenigmamus alludes to its enigmatic classification among rodents. The first specimens of the Laotian rock rat were found for sale as meat in a market, and subsequent expeditions discovered more individuals, suggesting that they may not be as rare as initially believed.

These rock rats inhabit limestone karsts in Laos and Vietnam, with some populations potentially being genetically isolated from one another. They are herbivores, primarily consuming leaves, grass, and seeds, but they may also feed on insects. They are believed to be nocturnal and are known for their docile nature. They move slowly with a distinctive duck-like gait that enables them to traverse rocky terrain effectively.