Using radiotelemetry to identify the home range and daily movement of a “living fossil”: the Laotian rock rat (Laonastes aenigmamus)

Abstract

The Laotian rock rat or Kha nyou (Laonastes aenigmamus) is a small mammal species that was discovered in Central Lao People's Democratic Republic (Lao PDR) in 1996. After this discovery, the Laotian rock rat was recognized as a living fossil of the family Diatomyidae, other members of which have been extinct more than 11 million years. Previous studies have been limited to the taxonomy of the species, but information on its behavior and ecology is still lacking. Our study on home range size and movement distances of the Laotian rock rat was conducted using radio tracking in Mouang-doy village, Phou Hin Poun National Biodiversity Conservation Area, central Lao PDR. We equipped four live-trapped Laotian rock rats (3 males and 1 female) with radio collars between December 2009 and January 2011. Radio-collared animals were tracked every thirty minutes and for at least five consecutive days per month. The averaged home ranges of the Laotian rock rat in the dry season and in the wet season were 1.69 ha (SD = 0.53; n = 4) and 1.49 ha (SD = 0.46; n = 3), respectively, and were not significantly different. The home ranges of radio-collared Laotian rock rats overlapped among individuals, and overlapped area between pairs of animals ranged from 30.21 to 75.89%. The mean daily movement distances were 1602 m (SD = 150.13; n = 3 individuals) and 1578 m (SD = 52; n = 3 individuals) for the dry season and the wet season, respectively, with no statistically significant difference. This study also indicated that the Laotian rock rat is cathemeral. We would suggest additional studies to better understand the behavioral ecology of the Laotian rock rats, especially with regards to the comparison between sexes and social organization.