PKWS, home to four species of macaques

TreesPKWS harbors a diverse community of macaque species from all major radiations of the genus: stumptailed macaques (Macaca arctoides), Assamese macaques (Macaca assamensis), northern pigtailed macaques (Macaca leonina), and rhesus macaques (Macaca mulatta). All of the above results are from work on one group of Assamese macaques, group AS. A second group of Assamese macaques has been habituated to a stage where the first standard observations procedures can be conducted in December 2011. The two groups are neighboring and share parts of their home range. The groups are surrounded by other Assamese macaque groups except towards the East for AS. For some directions it is established that there is a second neighbor beyond that. For many of these groups fecal samples have been collected under the sleep tree after the group had left. Analysis of these samples that are stored at Kasetsart University could help to verify the minimum number of groups living around the study groups. In any case it can be concluded that the groups are not isolated and that the population seems healthy.

Efforts have been made to habituate a group of pigtailed macaques in the study area. Unfortunately, the pigtailed macaques left the marked trail study area often and for extended periods of time so that habituation never was accomplished. It can be concluded that without radio collaring pigtailed macaques at PKWS cannot be habituated. The species is abundant in PKWS as evident from frequent sightings along the road from close to the entrance all the way to the queen’s palace in TKM.

During work on Assamese macaques and the habitation trials for pigtailed macaques no rhesus macaques were ever encountered in the study area. Rhesus macaques are regularly sighted along the road at and close to Salaprom. They may be relatively easy to habituate because the groups at Salaprom are used to humans. Studying rhesus macaques in PKWS would require the establishment of a new study area. Rhesus macaques are scientifically highly relevant because they are the most commonly used non-human primate model in biomedical research. Almost nothing is known, however, from the species in its natural environment.

Stumptail macaques were never seen during work on Assamese macaques and pigtailed macaques or along the road. The species is reported from ranger patrols on the plateau.

Macaque species diversity is unusually high at PKWS. Judging from observations in the study area some species seem to avoid each other or to have diverging ecological needs. It remains unknown what determines the species distribution across the sanctuary. The population of Assamese macaques appears to be large and healthy.