Strata Use by Sympatric Macaques (Macaca assamensis and M. Mulatta) in Nagarjun Forest of Shivapuri - Nagarjun National Park, Kathmandu, Nepal

Abstract

Using different habitat is a niche partitioning mechanism utilized by the primates. The use of forest strata by non-human primates is greatly dependent on the age, sex and the activities being performed. Limited studies have explored forest strata use pattern in macaques. This study aimed to compare the diurnal activity budget and forest strata use of Assamese macaques (Macaca assamensis) and rhesus macaques (M. mulatta) in Nagarjun Forest of ShivapuriNagarjun National Park, Kathmandu. Further it tested the difference in strata use brought by

the age-sex difference and the behavioral activities. The study was carried out from September

2022 to March 2023. The behavior recorded included (a) feeding, (b) moving (c) resting, and

(d) socializing.

Data on the behavior of the macaques were collected using the focal animal sampling method. For the forest strata use, instantaneous scan sampling was carried out at every 10 minute interval recording macaques’ sex, the height of the forest strata, and their behaviors on each observation. The data for Assamese macaque groups was collected for three consecutive days of every study week before switching to data collection for rhesus macaque groups. Analysis of the data was done using One-way ANOVA, Kruskal-Wallis test and MannWhitney

U test. The Assamese macaques spent majority of the diurnal time in the trees. Assamese macaques used arboreal strata significantly more (88.4%) whereas rhesus macaques were seen significantly more on the ground (62.72%). The use of strata for different age-sex group and behavioral activity vary significantly for both Assamese and rhesus macaques. Assamese macaques showed preference for ground while feeding and strata between 5–15 m for other behaviors. Rhesus macaques performed feeding, resting, moving and socializing behavior significantly more on the ground. This study showed that there is significant difference in the forest strata use between the sympatric Assamese macaques and rhesus macaques of Nagarjun Forest.