Diet Of Macaques Research Articles

Regional variation in the behavioral aspects of long-tailed macaques and its ecological determinants

Abstract Dietary composition and activity budgets of primate are affected by habitat characteristics. We described variations in activity budgets and dietary habits of free-ranging long-tailed macaques (Macaca fascicularis) in various habitats, including anthropogenic habitats, through a web-based survey, and tried to find determinants of the regional variation in the behavioral aspects of macaques. The activity budgets of the macaques were stable across sites regardless of geographic, climatic, and anthropogenic characteristics, but dietary composition varied among habitats; the percentage of fruits and seeds was significantly lower at higher latitudes. The plasticity of frugivory in response to regional variations in the food environment was similar to that of macaques inhabiting temperate regions. In habitats with strong human activity, the percentage of anthropogenic foods in the macaque diet was remarkably higher, and fruits and seeds was lower than that in natural habitats. Our results suggested that macaques showed high dietary adaptability to different habitats.

Linking gut microbiome with the feeding behavior of the Arunachal macaque (Macaca munzala)

Exploring the gut microbiome is an emerging tool for monitoring wildlife health and physiological conditions which often sustained under the variety of stresses and challenges. We analyzed gut microbiome of Arunachal macaque (Macaca munzala) of two disjunct populations from Arunachal Pradesh, India, to validate whether the geography or the feeding habits plays a principal role in shaping the gut microbiome in natural populations. We observed geography has a mere effect but feeding habits (i.e. feeding upon the leftover food and crop-raiding) significantly influenced the gut microbiome composition. The phylum Proteobacteria found to be enriched in leftover feeding group while phylum Bacteroidetes was differentially abundant in crop-raiding group. We observed predominant phyla Firmicutes followed by Proteobacteria and Bacteroidetes with the dominant classes represented by the Clostridia. Interestingly, one individual with known diarrheal/metabolic disorder exhibited complete dominance of the order Bacillales and showed 100% sequence similarity with genus Solibacillus. We raise concern that shift in diet of macaques may compel them to expose for various human diseases as two macaques feeding upon the leftover food exhibited dysbiotic gut microbiome. The present study provides the pragmatic evidences of how the alteration of food resources can harm the physiological condition of the macaques in wild and raises alarm to the forest officials/managers in strategise planting of natural food resources and monitor anthropogenic activities in the distribution of Arunachal macaques.

Retrospective Evaluation of a Minor Dietary Change in Non-Diabetic Group-Housed Long-Tailed Macaques (Macaca fascicularis).

Simple SummaryMacaques in captivity are prone to becoming overweight and obese, which may cause several health and welfare problems. Diet likely plays an important role herein. In an attempt to reduce overweight incidence and related health problems, a minor dietary change was implemented in our long-tailed macaque breeding colony. The provisioning of bread was replaced by grains and vegetables, while the basic diet of monkey chow remained the same. Overweight status did not differ after dietary change, but some biochemical parameters related to glycemic response and lipid metabolism improved. This study emphasizes the importance of evaluating husbandry changes and shows that relatively minor dietary adjustments may improve animal health and welfare.Macaques in captivity are prone to becoming overweight and obese, which may cause several health problems. A diet that mimics the natural diet of macaques may prevent these problems and improve animal welfare. Adjusting captive diets towards a more natural composition may include increasing fiber content and lowering the glycemic index, i.e., reducing the impact on blood glucose levels. Such a dietary change was implemented in our long-tailed macaque (Macaca fascicularis) breeding colony. The basic diet of monkey chow pellets remained the same, while the supplementary provisioning of bread was replaced by grains and vegetables. This study is a retrospective evaluation, based on electronic health records, that investigated whether this minor dietary change had a beneficial effect on relative adiposity and overweight-related health parameters in 44 non-diabetic, group-housed, female long-tailed macaques. Relative adiposity was measured with a weight-for-height index and blood samples were collected during yearly health checks. Glycemic response and lipid metabolism were evaluated using several biochemical parameters. Relative adiposity and overweight status did not differ after dietary change. Yet, relatively heavy individuals generally lost body weight, while relatively lean individuals gained body weight, leading to a more balanced body weight dynamic. Dietary change did not affect HbA1c and triglyceride levels, while fructosamine and cholesterol levels were significantly reduced. Thus, the minor dietary change had no significant effect on overweight status, but some biochemical parameters related to the risk of diabetes and cardiovascular disease were positively affected. This study emphasizes the importance of evaluating husbandry changes and that critically reviewing husbandry practices can provide valuable insights to improve animal health and welfare.

Food hypersensitivity-induced chronic gastrointestinal inflammation in a non-human primate model of diet-induced obesity.

Experimental non-human primate models of obesity are induced through the introduction of atypically calorically rich diets. Studies in captive-bred macaques show the development of obesity and diabetes with similar complications to humans including eye and kidney diseases, nerve damage associated with pain and blood vessel damage. Diets differ in outcomes and here we document inflammation of the gastrointestinal tract that can be exacerbated through these dietary interventions. Following baseline physiological evaluation of body composition, Southern pigtail macaques were given a high-fat diet (HFD) for three months. This HFD consisted of lard, grains (including gluten), dairy and fructose that was otherwise omitted from a standard macaque diet (Chow). Physiological parameters were then reassessed before animals were reverted back to standard Chow for a further three months (remission). Consumption of the HFD resulted in food-mediated hypersensitivity marked by chronic weight loss, alopecia, malabsorption, protein-losing enteropathy and gross diffuse intestinal villi atrophy and lamina propria hypertrophy. Physiological changes were more highly pronounced in female macaques suggesting sex-specific differences but could be fully reversed through change of diet. Care should be taken in choosing non-human primate HFD diets for creating experimental models of obesity because they can induce severe food-driven chronic inflammation of the gastrointestinal tract that can eventuate to diet-induced chronic wasting and mortality.

Status of urban populations of the long-tailed macaque (Macaca fascicularis) in West Sumatra, Indonesia.

We studied long-tailed macaque (Macaca fascicularis) populations in Padang, West Sumatra, Indonesia, focusing on the effect of human provisioning on their demography and dietary composition. We conducted a field survey at three sites in the city: Gunung Meru, Gunung Padang, and Gunung Panggilun. Mean troop size (range 28-68) and infant ratio (range 0.38-1.00) were greater in Gunung Meru, where the macaques have been highly provisioned, than at the other two study sites (troop size 10-15; infant ratio 0.00-0.33). The macaques at all sites consumed both natural and human foods, but dependence on the latter differed among sites: three-quarters of the diet of macaques in Gunung Meru consisted of human foods, while human foods comprised less than 5% of the macaque diet at the other sites. The ability of macaques to modify the proportion of human food is a behavioral flexibility that facilitates the survival of the long-tailed macaque in urban habitats. Without restrictions on provisioning, the degree of dependence of macaques on human foods and population size could increase, especially in Gunung Meru, and human-macaque conflict could escalate. In order to create an effective management policy for urbanized monkeys, long-term quantitative data on macaque behavior and monitoring of population parameters are required.

Western-style diet, with and without chronic androgen treatment, alters the number, structure, and function of small antral follicles in ovaries of young adult monkeys

To examine the small antral follicle (SAF) cohort in ovaries of adult rhesus monkeys after consumption of a Western-style diet (WSD), with or without chronically elevated androgen levels since before puberty. Cholesterol or T (n = 6 per group) implants were placed SC in female rhesus macaques beginning at 1year of age (prepubertal), with addition of a WSD (high fat/fructose) at 5.5years (menarche approximately 2.6years). Ovaries were collected at 7years of age. One ovary per female was embedded in paraffin for morphologic and immunohistochemical analyses. The SAFs (<2.5mm) were dissected from the other ovary obtained at or near menses in a subgroup of females (n = 3 per group) and processed for microarray analyses of the SAF transcriptome. Ovaries of adult monkeys consuming a standard macaque diet (low in fats and sugars) were obtained at similar stages of the menstrual cycle and used as controls for all analyses. Primate research center. Adult, female rhesus monkeys (Macaca mulatta). None. Histologic analyses, SAF counts and morphology, protein localization and abundance in SAFs, transcriptome in SAFs (messenger RNAs [mRNAs]). Compared with controls, consumption of a WSD, with and without T treatment, increased the numbers of SAFs per ovary, owing to the presence of more atretic follicles. Numbers of granulosa cells expressing cellular proliferation markers (pRb and pH3) was greater in healthy SAFs, whereas numbers of cells expressing the cell cycle inhibitor (p21) was higher in atretic SAFs. Intense CYP17A1 staining was observed in the theca cells of SAFs from WSD with or without T groups, compared with controls. Microarray analyses of the transcriptome in SAFs isolated from WSD and WSD plus T-treated females and controls consuming a standard diet identified 1,944 genes whose mRNA levels changed twofold or more among the three groups. Further analyses identified several gene pathways altered by WSD and/or WSD plus T associated with steroid, carbohydrate, and lipid metabolism, plus ovarian processes. Alterations in levels of several SAF mRNAs are similar to those observed in follicular cells from women with polycystic ovary syndrome. These data indicate that consumption of a WSD high in fats and sugars in the presence and absence of chronically elevated T alters the structure and function of SAFs within primate ovaries.

Forest seasonality shapes diet of limestone-living rhesus macaques at Nonggang, China.

Limestone forests are an unusual habitat for primates, but little information is available for the genus Macaca in such habitats, making a comparative understanding of extant limestone primates' behavioral adaptation incomplete. We collected data on the diet of rhesus macaques (Macaca mulatta) in a limestone habitat at Nonggang Nature Reserve, southwestern Guangxi, China, and examined the effects of forest seasonality on their diet. Our results indicated that a total of 114 species of plants are consumed by macaques. Young leaves are a preferred food, accounting for 48.9 and 56.9% of the overall diets. One group significantly increased young leaf consumption in response to availability. Fruits contributed to only 27.3 and 28.7% of overall diet. The macaque diet varied according to season. They fed on more fruits in the rainy season. Consumption of mature leaves increased when the availability of young leaves and fruits declined in the dry season, indicating that mature leaves are a fallback food for macaques in a limestone habitat. Similar to sympatric Assamese macaques, Bonia saxatilis, a shrubby, karst-endemic bamboo was consumed by rhesus macaques throughout the year, and was the top food species through most of the year, suggesting that bamboo consumption represents a key factor in the macaque's dietary adaptation to limestone habitat.

Influence of Heavy Snow on the Feeding Behavior of Japanese Macaques (Macaca Fuscata) in Northern Japan

Natural disasters can degrade primate habitat and alter feeding behavior. Here, we examined the influence of unusually heavy snow on diet and feeding-site use by Japanese macaques (Macaca fuscata) in northern Japan. To compare the winter-feeding behavior under different snow conditions, we recorded the plant species foraged on by macaques in multiple transects of the Shirakami Mountains from 2008 to 2012 (excluding 2011). We used cluster analysis to describe foraged plant assemblages, and applied multiple dimensional scaling and decision tree modeling to evaluate annual variation in feeding-site use by macaques. Our cluster analysis revealed five types of foraged plant assemblages. The proportion of each type present in transects varied considerably across the years, indicating that the diet of macaques in heavy snow conditions was influenced more by resource accessibility than by preference. Multiple dimensional scaling and decision tree modeling demonstrated that heavy snow conditions restricted feeding-site use. Moreover, the distribution of refuges relative to severe external ambient environments was a stronger limiting factor for feeding-site use than was the availability of food resources. While most primate species facing unexpected starvation employ risk-prone foraging tactics (i.e., choosing the option with higher pay-off by accepting risk), Japanese macaques have a tendency to adopt risk-averse foraging behavior (i.e., minimizing energy loss when searching for preferred diet items under long-lasting heavy snow conditions), because winters with temperatures below freezing have higher thermoregulatory costs.

Food resources of the wild Barbary macaque (Macaca sylvanus) in high‐altitude fir forest, Ghomaran Rif, Morocco

A small geographically isolated population of the Barbary macaque inhabits a high‐altitude fir forest habitat (Abies pinsapo) in the Ghomaran region of the Rif mountains of northern Morocco. The climate of this region is Mediterranean, but the altitude (1600–2100 m) causes winters to be cold (as low as ‐8.0 d̀C) with snow occurring from November to May (snowfall as deep as 1.5 m). The primary winter feeding adaptation is the ability to ingest high quantities of fir foliage; in spring, the macaques took a high diversity of leafy food items from all vegetation layers; in summer, the macaques foraged terrestrially for a high diversity of food items including seeds, small fruits, bulbous geophytes, and animal foods (including tadpoles from small streams); in autumn, the macaques returned to arboreal foraging, primarily feeding on oak acorns (Quercus ilex), fir seeds and yew fruit (Taxus baccata). The macaques were capable of ingesting 100 of 195 (51%) of all identified plant species in the region, although during the four‐month winter, the macaques only averaged 12.5 common food items. A comparison of the study area with the prime habitat of the Barbary macaque‐the high‐altitude cedar forests of the Moroccan Moyen Atlas‐indicates that climate and vegetation physiognomy are highly similar in both regions. Correspondingly, there is a high degree of similarity in macaque diet in both regions in terms of feeding behaviour by season, food diversity and specific feeding techniques. In the Ghomara, the winter feeding adaptation of fir foliage eating parallels that of the Barbary macaque in cedar forest (winter foraging for cedar foliage). This enables the Barbary macaque to exploit the Ghomaran fir forest habitat during the cold, snowy winters much the same as it does cedar forest habitat throughout a major portion of its geographical range.