Activity pattern and habitat association of Assamese macaques Macaca assamensis McClelland, 1840 in Shivapuri Nagarjun National Park, Nepal

Assamese macaque Macaca assamensis McClelland, 1840 is one of the primate species with narrow distribution range and the least exploration. This study investigated the diurnal activity of Assamese macaque and association with the vegetation in Nagarjun Forest of Shivapuri Nagarjun National Park, Nepal. Behaviour sampling including Instantaneous sampling and Ad-libitum sampling (7:30 AM – 4:30 PM) along with vegetation survey (20 m × 20 m plots) were applied. The Raniban Barrack troop of Assamese macaque composed of 12 individuals was observed for a total of 225 hours to record the macaque’s diurnal activity. The troop spent 28% time in inactive, 25% in grooming, 23% in foraging, 23% in locomotion and 1% in fighting. Assamese macaque troop spent more time in Schima wallichii possessing 25.91%, 36.29% and 41.22% for foraging, locomotion and inactive respectively of the diurnal time. Altogether, 67 plant species (herbs, shrubs, trees and climbers) were documented from vegetation analysis. Schima wallichii and Ardisia macrocarpa were dominated the habitat. Paired t-test revealed significant difference in foraging (df = 24, P = 0.010) and inactive (df = 24, P = 0.003) between the morning and day observational phases. The findings of this study shed light on the food preference and microhabitat use by the protected Assamese macaque in Nepal that assists to formulate the management plans for the species.

The effect of reproductive state on activity budget, feeding behavior, and urinary C-peptide levels in wild female Assamese macaques

The source of maternal energy supporting reproduction (i.e., stored or incoming) is an important factor determining different breeding strategies (capital, income or mixed) in female mammals. Key periods of energy storage and allocation might induce behavioral and physiological shifts in females, and investigating their distribution throughout reproduction helps in determining vulnerable phases shaping female reproductive success. Here, we examined the effects of reproductive state on activity budget, feeding behavior, and urinary C-peptide (uCP) levels, a physiological marker of energy balance, in 43 wild female Assamese macaques (Macaca assamensis). Over a 13-month study period, we collected 96,266 instantaneous records of activity and 905 urine samples. We found that early lactating females and non-gestating–non-lactating females follow an energy-saving strategy consisting of resting more at the expense of feeding and consuming mostly fruits which contributed to enhancing their energy intake and feeding efficiency. We found an opposite pattern in gestating and late lactating females who feed more at the expense of resting and consume mostly seeds, providing a fiber-rich diet. Storing food into cheek pouches increased throughout gestation while it decreased all along with lactation. Lastly, we found the highest uCP levels during late gestation. Our results reflect different feeding adaptations in response to the energetic costs of reproduction and suggest a critical role of fat accumulation before conception and metabolizing fat during gestation and lactation. Overall, our study provides an integrative picture of the energetics of reproduction in a seasonal species and contributes to our understanding of the diversity of behavioral and physiological adaptations shaping female reproductive success. Significance statement To offset their substantial energetic investment in reproduction, mammalian females may modify their behavior and the way they extract energy from their environment. In addition, as a result of heightened energy expenditure, female reproduction might trigger physiological shifts. To date, most studies investigated the energetic costs of female reproduction using either a behavioral or a physiological approach. To arrive at a more comprehensive picture, we combined behavioral data with a physiological marker of energy balance, i.e., urinary C-peptide, in a seasonal primate species in its natural habitat. Our results indicate that throughout the reproductive cycle, behavioral and physiological adaptations operate concomitantly, inducing modifications in female activity budget, feeding behavior, and suggesting shifts in fat use. Overall, our results illustrate the relevance of combining data on behavior and hormones to investigate breeding strategies in coping with the energetic costs of reproduction.

Feeding ecology of Assamese macaques (Macaca assamensis) troops in Kaligandaki and Budhigandaki River basins of central Nepal

Ghimire SC, Khanal L, Chalise MK. 2021. Feeding ecology of Assamese macaques (Macaca assamensis) troops in Kaligandaki and Budhigandaki River basins of central Nepal. Biodiversitas 22: 2625-2634. Seasonal fluctuations in the availability of key food resources impact the foraging behavior of animals. This study aimed to examine the seasonal variations in feeding time of Assamese macaques (Macaca assamensis) in the sub-tropical deciduous riverine forest environment of central Nepal. Two troops of Nepal population of Assamese macaques, a troop from Kaligandaki River Basin (KRBT) and the next from Budhigandaki River Basin (BRBT) were studied by focal animal sampling method. Data from systematic behavioral observations were analyzed with reference to that of the vegetation surveys. Assamese macaques invested more than two-fifths (>40%) of the diurnal time on feeding. The KRBT consumed 71 plant species and the BRBT relied on 69 food plants. Leaves, mature and young, constituted the most dominant food item followed by the fruits and seeds. The two study troops inhabiting highly similar habitats of food plants (Sorensen’s Similarity Index = 0.93) didn’t have a significant difference in the selection of food-plant parts. However, the remarkable temporal difference in feeding plant parts was observed in concordance with their seasonal availability. Young leaves, when available during the spring and pre-monsoon were the major food items. Contrastingly, mature leaves were the food items during the winter on which animals were forced to rely when young leaves were scarce. We conclude that food choice and time investment on the feeding of different plant parts differ depending on the availability of food in the area. Macaques living in comparable habitats with similar food plants have analogous food choices and time investments.

Pet Macaques in Vietnam: An NGO’s Perspective

In this article, we attempt to characterize the widespread trade in pet macaques in Vietnam. Data on confiscations as well as surrenders, releases, and individuals housed at rescue centers across Vietnam for 2015–2019 were opportunistically recorded. Data comparisons between Education for Nature Vietnam and three government-run wildlife rescue centers show that at least 1254 cases of macaque keeping occurred during the study period, including a minimum of 32 Assamese macaques (Macaca assamensis), 158 long-tailed macaques (Macaca fascicularis), 291 Northern pig-tailed macaques (Macaca leonina), 65 rhesus macaques (Macaca mulatta), and 110 stump-tailed macaques (Macaca arctoides). A minimum of 423 individuals were confiscated, and at least 490 individual macaques were released. Three semi-structured interviews were conducted with two key Animals Asia (a non-governmental organization) colleagues and their insights are presented. Although we recognize that the data included are limited and can serve only as a baseline for the scale of the macaque pet trade in Vietnam, we believe that they support our concern that the problem is significant and must be addressed. We stress the need for organizations and authorities to work together to better understand the issue. The keeping of macaques as pets is the cause of serious welfare and conservation issues in Vietnam.

Female Assamese macaques bias their affiliation to paternal and maternal kin

Forming strong social bonds can lead to higher reproductive success, increased longevity, and/or increased infant survival in several mammal species. Given these adaptive benefits, understanding what determines partner preferences in social bonding is important. Maternal relatedness strongly predicts partner preference across many mammalian taxa. The role of paternal relatedness, however, has received relatively little attention, even though paternal and maternal kin share the same number of genes, and theoretically similar preferences would therefore be expected for paternal kin. Here, we investigate the role of maternal and paternal relatedness in female affiliation in Assamese macaques (Macaca assamensis), a species characterized by a relatively low male reproductive skew. We studied a wild population under natural conditions using extensive behavioral data and relatedness analyses based on pedigree reconstruction. We found stronger affiliative relationships and more time spent grooming between maternal kin and paternal half-sisters compared with nonkin, with no preference of maternal over paternal kin. Paternally related and nonrelated dyads did not form stronger relationships when they had less close maternal kin available, but we would need a bigger sample size to confirm this. As expected given the low reproductive skew, affiliative relationships between paternal half-sisters closer in age were not stronger than between paternal half-sisters with larger age differences, suggesting that the kin bias toward paternal kin was not mediated by age similarity. An alternative way through which paternal kin could get familiarized is mother- and/or father-mediated familiarity.