A comparative assessment of external morphological traits between Macaca munzala, Tawang and Macaca assamensis, Goalpara population in Northeast India.

The present study aimed to conduct a comparative assessment of the external morphology, relative tail length and colour variation (RGB additive colour model) of Macaca munzala, Tawang and Macaca assamensis, Goalpara (southern Brahmaputra population), using a non-invasive photogrammetry method. The study revealed that the relative tail length of M. munzala (0.43 ± 0.03) is similar to that of M. assamensis assamensis, a subspecies of M. assamensis. On the other hand, the relative tail length of M. assamensis, Goalpara (0.61 ± 0.04) is similar to M. assamensis pelops, the other subspecies of M. assamensis. A total of 12 external morphological traits were observed and similarities found between the two studied populations. The study also found that the species-specific traits of M. munzala such as "dark patch of the crown whorl", "dark patch of hair at the temporal side", "spectacle appearance around eyes" and "whip-like tail appearance" in the infant and "stocky tail" are present in M. assamensis, Goalpara as well. Likewise, the "chin and cheek whiskers" are found in adult female individuals of both species. The comparative assessment of the dorsal coat colour (RGB value) revealed a darker brown dorsal coat in M. munzala (R 123.14 ± 11.62; G 107.71 ± 10.37, B 89.43 ± 9.21) than in M. assamensis, Goalpara (R 136 ± 23.57, G 112 ± 15.63, B 97.83 ± 13.04). The comparative assessment of facial skin colour among the adult individuals showed that the male M. munzala has darker brown facial skin than that of M. assamensis, whereas the female M. munzala shows darker reddish facial skin compared to M. assamensis, Goalpara. The species-specific traits of M. leucogenys were also compared, and the traits "chin and cheek whiskers", "darker dorsal coat" and "round penile" appearance have a striking resemblance to those of the M. munzala population of Tawang. Thus, the external morphological traits that are being used to distinguish these macaque species are highly variable even within the same species, and there is an urgent need to identify more precise species-specific morphological traits.

Diet and feeding ecology of the western hoolock gibbon (Hoolock hoolock) in a tropical forest fragment of Northeast India.

Forest fragmentation alters plant species diversity and composition, and causes diverse affects on the feeding behavior of wild primates. We investigated the feeding behavior and diet of two groups of western hoolock gibbon (Hoolock hoolock) inhabiting a small isolated forest patch (21 km2) in Hollongapar Gibbon Wildlife Sanctuary, Assam, Northeast India, over a year using focal animal sampling. H. hoolock adults spent, on average, 35.2% of their total annual activity budget on feeding, and fed on young leaves, mature leaves, flowers, fruits, petioles, buds and also on animal matter. There was marked seasonal variation in the proportions of the dietary items consumed. Fruits accounted for an average of 51% (range 34-71% per month) of feeding time over the year. This highly frugivorous diet may limit the ability of the species to survive in small and disturbed forest fragments. A total of 54 plant species (32 families) were consumed by the focal groups during the study period, but there were variations between months in the selection of these plant species. Non-tree species such as lianas were among the most highly selected species in the diet. Moraceae, comprising ten species, was the most dominant family among the food plants, accounting for 36% of annual feeding time. The present study presents quantitative and qualitative data on dietary composition, preference and selection of food plants of H. hoolock in a fragmented habitat, which can contribute to the restoration and manipulation of degraded habitats of H. hoolock.

Predictive distribution modeling and population status of the endangered Macaca munzala in Arunachal Pradesh, India.

The present study reports the population of Macaca munzala in Tawang and West Kameng districts and its predictive distribution range in Arunachal Pradesh, estimated using ecological niche modeling. Environmental variables and occurrence data from a preliminary survey were used in the MaxEnt modeling, a statistical model to know the potential distribution area of the enigmatic species in Arunachal Pradesh. Later, a population survey was carried out in Tawang and West Kameng districts of the state following existing trails and paths. The distribution model revealed that only 2.4% of the total landmass of the state is potential distribution habitat range for M. munzala, whereas 10.19% of the total area of the two districts were shown to be potential habitat of the species. A total number of 971 individuals (including two solitary males) comprising 41 troops of M. munzala were recorded during the population survey. The mean troop size was 23.63 ± 1.21 individuals per troop ranging from 12 to 44 individuals. On average, M. munzala troops were comprised of juveniles (30.37%), adult females (23.83%), infants (18.22%), adult males (11.53%), sub-adult females (9.81%), and sub-adult males (6.23%). Our observed population size of M. munzala is higher in Tawang and West Kameng districts when compared with the earlier available records. This study showed the potential distribution of M. munzala based on environmental variables and the present population status in Tawang and West Kameng districts of Arunachal Pradesh, India.