A STUDY ON REPRODUCTIVE BEHAVIOUR OF NICOBAR LONG-TAILED MACAQUE (MACACA FASCICULARIS UMBROSUS) IN NICOBAR ISLANDS, INDIA

Abstract

Nicobar long-tailed macaques (Macaca fascicularis umbrosus) live in three small isolated catastrophic prone Nicobar Islands. This study was conducted to understand the strategies adapted by these macaques to survive on such stressful condition, and compare it with other sub-species distributed in varying environmental conditions. The study suggested a high degree of similarities in demographic traits and social organization between the sub-species, which reflected the high adaptability of these macaques to manage the life-history traits by coping with the stressful condition. Contrasting to other sub-species, the distinct behavioral traits like the variation in age-sex ratio and non-seasonal breeding pattern in these macaques are the adaptive strategies to achieve the conservative life-history traits to maximize the reproductive output. Competition for mate resources was very evident in M. f. umbrosus, where individuals of both the sexes were involved in intra and inter-sexual competition to increase their reproductive success. Social hierarchy has a direct impact on the heterogeneous distribution of mate and food resources between individuals with different social status, which ultimately shapes the social organization in M. f. umbrosus. Consequently, to balance the disadvantages of living in such hierarchical group, individuals make a trade-off by adopting different behavioral strategies through policing specific inter-individual relationships. These macaques were involved in between-group contest to compete for food and mate resources rather than the territory defense. This study provided first-ever information about demography, social organization, reproductive behaviors, birth seasonality, and intra and inter-group competition in Nicobar long-tailed macaques. It also revealed that in due course of interactions with its environment, a species could become flexible with life history traits and adopt different strategies to increase survivability as well as inclusive fitness.