Population Of Rhesus Macaques Research Articles

Pre and Post Sterilization Behaviour Studies of Rhesus macaque (Macaca mulatta) in Himachal Pradesh, India

Abstract: Rhesus Macaque (Macaca mulatta) population in India has been on a rise due to their high breeding rate and ability to acclimatize to various environments (Imam 2013). They are often seen in Human habitations especially in agricultural fields, raiding crops and becoming a nuisance to the farmers. According to agricultural department, the marauding macaques have raided agricultural crops worth Rs 185 crore and horticulture crops worth Rs 38 crore in various districts of HP in 2014. To address this menace, sterilization programme is carried out at respective Monkey sterilization centre (MSC’s) established at 8 monkey affected districts across Himachal Pradesh. This study aims to investigate and understand the various behavioural changes that may occur (intra specific, social , feeding, stress/aggression ) in the period of post sterilization of Rhesus macaque. The proposed study site for this project is a Village called Gopalpur located in Kangra District of Himachal Pradesh. For pre-sterilization monitoring, a virgin Troupe was identified and selected for capture based on the MSC’s record on capture locations and sterilized monkeys. The virgin troupe was monitored for their behaviour which included changes and their usual aggression, Feeding, grooming, sleeping, and mating and home range, for a period of 3 weeks. 100 % capture of this troupe was aimed for sterilization at a time. But failure of the same, the remaining population was to be monitored for their behavioural changes due to separation from their parent troupe. Capturing Rhesus of Chamunda Area near the addressed site was challenging due to many reasons which are discussed in the report. Three monkeys were caught successfully out of which two escaped and one turned out to be pregnant. The identified troupe couldn’t be captured and sterilized to study their post behavioural changes. The pregnant monkey was released back at the point of capture as it can’t be sterilized. This study on presterilization behaviour will form a baseline data for future studies on their post-sterilization behavioural changes. The study will also help in streamlining the monkey capturing process. Keywords: Rhesus macaque, Behaviour, Monkey sterilisation centre, MSC, Sterilisation program.

Factors influencing the success of male introductions into groups of female rhesus macaques: Introduction technique, male characteristics and female behavior.

In captive populations of rhesus macaques, novel adult males are commonly introduced to female groups every few years to prevent inbreeding, which mimics male dispersal in wild macaque populations. However, introducing adult males is challenging because macaques are aggressive to newcomers, which can result in serious injuries. Efforts to reduce trauma risk during the introduction process and increase the probability of success are needed. Here we investigate the impact of multiple factors, including male attributes (e.g., age, weight, rank, and experience), introduction method (punctuated vs. continual exposure to females), and female behavior, on males' trauma risk and integration success. We studied eight introductions of multimale cohorts (3-7 males each; N = 36 total) into existing female groups of rhesus macaques at the Yerkes National Primate Research Center. Four cohorts were introduced using the punctuated exposure method where adult males were moved each morning from run housing to the females' indoor enclosure and returned to run housing in the afternoon, and four cohorts were introduced using the continual exposure method where adult males were moved to an introduction enclosure attached to the females' outdoor compound, allowing males to live in protected contact next to the female group continuously. Generalized linear mixed models fitted to trauma risk (e.g., latency to first trauma; total trauma count) and success or failure to integrate (i.e., continual residence within the female group for greater than 53% of days within a 28-day window after first overnight stay) showed that continual exposure to females in the introduction enclosure reduced male trauma risk and increased the likelihood of successful integration compared to punctuated exposure. Males received less trauma when they received a higher rate of grooming from females. Male attributes had no effect. These findings highlight the importance of introduction technique and female behavior in the process of males' social integration into female groups.

Rhesus macaques build new social connections after a natural disaster

Climate change is increasing the frequency and intensity of weather-related disasters such as hurricanes, wildfires, floods, and droughts. Understanding resilience and vulnerability to these intense stressors andtheir aftermath could reveal adaptations to extreme environmental change. In 2017, Puerto Rico suffered its worst natural disaster, Hurricane Maria, which left 3,000 dead and provoked a mental healthcrisis. Cayo Santiago island, home to a population of rhesus macaques (Macaca mulatta), was devastated by the same storm. We compared social networks of two groups of macaques before andafter the hurricane and found an increase in affiliative social connections, driven largely by monkeysmost socially isolated before Hurricane Maria. Further analysis revealed monkeys invested inbuilding new relationships rather than strengthening existing ones. Social adaptations to environmental instability might predispose rhesus macaques to success in rapidly changing anthropogenic environments.

Endocranial volume is variable and heritable, but not related to fitness, in a free-ranging primate

Large relative brain size is a defining characteristic of the order Primates. Arguably, this can be attributed to selection for behavioral aptitudes linked to a larger brain size. In order for selection of a trait to occur, the trait must vary, that variation must be heritable, and enhance fitness. In this study, we use a quantitative genetic approach to investigate the production and maintenance of variation in endocranial volume in a population of free-ranging rhesus macaques. We measured the endocranial volume and body mass proxies of 542 rhesus macaques from Cayo Santiago. We investigated variation in endocranial volume within and between sexes. Using a genetic pedigree, we estimated heritability of absolute and relative endocranial volume, and selection gradients of both traits as well as estimated body mass in the sample. Within this population, both absolute and relative endocranial volume display variation and sexual dimorphism. Both absolute and relative endocranial volume are highly heritable, but we found no evidence of selection on absolute or relative endocranial volume. These findings suggest that endocranial volume is not undergoing selection, or that we did not detect it because selection is neither linear nor quadratic, or that we lacked sufficient sample sizes to detect it.

Social Adversity Impacts on the Rhesus Macaque Immune System Resemble Those of Aging

Social adversity can impact immune function and is associated with increased morbidity and mortality. Many of these immune-related changes resemble the effects of the natural aging process. To date, little is known about the effects of social adversity on the immune system change across the lifetime. Here, we investigated how aging and social adversity (measured as social status) impact immune cell proportions. We performed flow cytometry on peripheral whole blood from a population of free-ranging rhesus macaques to quantify changes on immune cell proportions across the lifespan (n=99) and across different social statuses (n=53). Overall, we found that high adversity recapitulated the effects of aging. We found significant shared decreases in CD3+/CD4+ T cell proportions and corresponding increases in CD3+/CD8+ T cell proportions between individuals of older ages and low social status. These findings suggest that social adversity has similar effects to aging on T cell proportions, possibly affecting the T cell component of the immune response. In contrast, CD3+/CD4+/CD25+ T regulatory cell proportions increased with age, which is typical of normal aging. Contrary to our expectations, these cells were less abundant in low status individuals, indicating some overall regulatory immune deficits specific to lower status individuals. CD3+/CD8+/CD25+ T regulatory cells, which contribute to self-tolerance, were higher in high status individuals, suggesting that overall primary immune regulatory cells can be affected by social adversity and impair the regulation of inflammation. We provide evidence that social adversity alters immune cell proportions, implicating it in the development of inflammatory and/or aging-related diseases.

Germline transmission of donor, maternal and paternal mtDNA in primates.

What are the long-term developmental, reproductive and genetic consequences of mitochondrial replacement therapy (MRT) in primates? Longitudinal investigation of MRT rhesus macaques (Macaca mulatta) generated with donor mtDNA that is exceedingly distant from the original maternal counterpart suggest that their growth, general health and fertility is unremarkable and similar to controls. Mitochondrial gene mutations contribute to a diverse range of incurable human disorders. MRT via spindle transfer in oocytes was developed and proposed to prevent transmission of pathogenic mtDNA mutations from mothers to children. The study provides longitudinal studies on general health, fertility as well as transmission and segregation of parental mtDNA haplotypes to various tissues and organs in five adult MRT rhesus macaques and their offspring. MRT was achieved by spindle transfer between metaphase II oocytes from genetically divergent rhesus macaque populations. After fertilization of oocytes with sperm, heteroplasmic zygotes contained an unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mitochondrial (mt)DNA. MRT monkeys were grown to adulthood and their development and general health was regularly monitored. Reproductive fitness of male and female MRT macaques was evaluated by time-mated breeding and production of live offspring. The relative contribution of donor, maternal, and paternal mtDNA was measured by whole mitochondrial genome sequencing in all organs and tissues of MRT animals and their offspring. Both male and female MRT rhesus macaques containing unequal mixture of three parental genomes, i.e. donor (≥97%), maternal (≤3%), and paternal (≤0.1%) mtDNA reached healthy adulthood, were fertile and most animals stably maintained the initial ratio of parental mtDNA heteroplasmy and donor mtDNA was transmitted from females to offspring. However, in one monkey out of four analyzed, initially negligible maternal mtDNA heteroplasmy levels increased substantially up to 17% in selected internal tissues and organs. In addition, two monkeys showed paternal mtDNA contribution up to 33% in selected internal tissues and organs. N/A. Conclusions in this study were made on a relatively low number of MRT monkeys, and on only one F1 (first generation) female. In addition, monkey MRT involved two wildtype mtDNA haplotypes, but not disease-relevant variants. Clinical trials on children born after MRT will be required to fully determine safety and efficacy of MRT for humans. Our data show that MRT is compatible with normal postnatal development including overall health and reproductive fitness in nonhuman primates without any detected adverse effects. 'Mismatched' donor mtDNA in MRT animals even from the genetically distant mtDNA haplotypes did not cause secondary mitochondrial dysfunction. However, carry-over maternal or paternal mtDNA contributions increased substantially in selected internal tissues / organs of some MRT animals implying the possibility of mtDNA mutation recurrence. This work has been funded by the grants from the Burroughs Wellcome Fund, the National Institutes of Health (RO1AG062459 and P51 OD011092), National Research Foundation of Korea (2018R1D1A1B07043216) and Oregon Health & Science University institutional funds. The authors declare no competing interests.

Rhesus Macaques Build New Social Connections after a Natural Disaster

Climate change is increasing the frequency and intensity of weather-related disasters such as hurricanes, wildfires, floods and droughts. Understanding resilience and vulnerability to these intense stressors and their aftermath will be critical for species conservation and human adaptation. In 2017, Puerto Rico suffered its worst natural disaster, Hurricane Maria, which left 3000 dead and fostered a mental health crisis. Cayo Santiago, home to a population of rhesus macaques (Macaca mulatta), was devastated by the same storm. We compared social networks of two groups of macaques before and after the hurricane and found an increase in affiliative social connections, driven largely by monkeys most isolated before Hurricane Maria. Partner-preference analysis revealed monkeys invested in building new relationships rather than strengthening existing ones. Evolved adaptations to environmental stochasticity may predispose rhesus macaques to success in rapidly changing anthropogenic environments.

SARS-CoV-2 surveillance for a non-human primate breeding research facility.

BackgroundThe emergence of SARS‐CoV‐2 and the ensuing COVID‐19 pandemic prompted the need for a surveillance program to determine the viral status of the California National Primate Research Center non‐human primate breeding colony, both for reasons of maintaining colony health and minimizing the risk of interference in COVID‐19 and other research studies.MethodsWe collected biological samples from 10% of the rhesus macaque population for systematic testing to detect SARS‐CoV‐2 virus by RT‐PCR and host antibody response by ELISA. Testing required the development and validation of new assays and an algorithm using in laboratory‐developed and commercially available reagents and protocols.Results and ConclusionsNo SARS‐CoV‐2 RNA or antibody was detected in this study; therefore, we have proposed a modified testing algorithm for sentinel surveillance to monitor for any future transmissions. As additional reagents and controls become available, assay development and validation will continue, leading to the enhanced sensitivity, specificity, accuracy, and efficiency of testing.

Unparalleled Rapid Evolution of KIR Genes in Rhesus and Cynomolgus Macaque Populations.

The killer cell Ig-like receptors (KIR) modulate immune responses through interactions with MHC class I molecules. The KIR region in large cohorts of rhesus and cynomolgus macaque populations were characterized, and the experimental design enabled the definition of a considerable number of alleles (n = 576) and haplotypes, which are highly variable with regard to architecture. Although high levels of polymorphism were recorded, only a few alleles are shared between species and populations. The rapid evolution of allelic polymorphism, accumulated by point mutations, was further confirmed by the emergence of a novel KIR allele in a rhesus macaque family. In addition to allelic variation, abundant orthologous and species-specific KIR genes were identified, the latter of which are frequently generated by fusion events. The concerted action of both genetic mechanisms, in combination with differential selective pressures at the population level, resulted in the unparalleled rapid evolution of the KIR gene region in two closely related macaque species. The variation of the KIR gene repertoire at the species and population level might have an impact on the outcome of preclinical studies with macaque models.

Probiotics and animal feed in primates feeding

This paper presents the results of experiments on primates feeding. In diet structures that were used animal feed, of which fish flour is the most valuable, as found, for monkeys, due to its unique chemical composition. And the effect of the probiotic complex “Bactistatin” on the digestibility of feed in the diet of rhesus monkeys was studied. This preparation belongs to the new generation of probiotics. It is a biological product with immobilized probiotic strains and their metabolites. The study was conducted on a large population of male rhesus macaques in enclosure conditions. Feeding diets, their nutritional value as a result of the inclusion of fish flour in the amount of 18% were studied. And also, the effect of “Bactistatin” in the amount of 3 g/head, on the formation of symbiotic microflora of the gastrointestinal tract, was studied in order to improve the absorption of nutrients in complete feed. Changes in homeostasis during the experiment were controlled by hematological and biochemical parameters of the blood of both experimental and control primates. At the end of the experiment, the cost of feed, nutrients, and exchange energy per head was calculated. The experimental data obtained were analyzed and mathematically processed.

Living near the limits: Effects of interannual variation in food availability on diet and reproduction in a temperate primate, the Taihangshan macaque (Macaca mulatta tcheliensis).

Nutrient intake of animals is influenced by an interplay of external and internal factors, such as food availability and reproductive state, respectively. We used the nutritional geometry framework to analyze individual-based data on energy and nutrient intake in relation to reproductive state in a population of rhesus macaques (Macaca mulatta tcheliensis), which live in a harsh high-latitude habitat, the Taihangshan mountains of China, and exhibit strong reproductive seasonality. We combined data over a 3-year period on food availability, diets, reproductive output, and components of maternal investment to understand how Taihangshan macaques respond to variation in food availability and nutrition in reproduction. Our results show there was high interannual variation in availability of an important staple source of fat and carbohydrates (nonprotein energy), seeds of oak (Quercus spp). Despite this variability in seed availability skewing the dietary macronutrient ratios considerably (from 12.96% to 30.12% dietary energy from protein), total metabolizable energy intake was maintained across years during pregnancy. Lactating females had higher mean daily energy intakes than pregnant females. As in pregnant females, energy intake was maintained constant across years, but only when seed availability enabled the contribution of available protein to energy intake to be maintained between 15.32% (2013) and 17.97% (2015). In 2014, when seeds were scarce, lactating females had a shortfall in energy intake compared with 2013 and 2015. This corresponded with a reduction in the number of females giving birth (11 out of 23), but there was no interannual difference in survival rates. Compared to 2013 and 2015, in 2014 females had greater weight loss (drew on body reserves), moved less, and spent more time nursing their offspring. We discuss implications of these results for range limitation in Taihangshan macaques.

Musculoskeletal injuries: prevalence and severity in free-range rhesus macaques (Macaca mulatta) of Himalayan Shivalik Hills, Northern India

ABSTRACT The present study was conducted to estimate prevalence and nature of various musculoskeletal injuries in populations of free-ranging rhesus macaques in Shivalik Hills of Himachal Pradesh in Northern India. Data were collected over a period of 2 years and analyzed in relation to sex, age-group and season. In total, 1522 (44.6%) cases of musculoskeletal injuries were recorded; of these, 645 (47.1%) were males and 877 (43%) were females. Data revealed that differences observed between sex, season and age were statistically significant. Musculoskeletal injuries were more common during winter season followed by monsoon and then summer (27.4%). Males (47.1%) were injured more frequently than females (43.1%), while adults (47.9%) were injured more frequently than juvenile (42.8%) and young ones (28.8%). Of all the musculoskeletal injuries, wounds (84.5%) were most common followed by fractures (7.2%), amputations (4.5%) and snares/pellets (3.9%). The result from present study indicated that musculoskeletal injuries were frequent in rhesus macaque population studied. Musculoskeletal injuries occurring throughout year likely reflect the multiple causes viz predation, disease, vehicle trauma and electrocution, which may act independently or jointly. Understanding the role primates play in local culture and religion, therefore, is essential for understanding the underlying basis of commensalisms and conflict.

Population estimate and management options for introduced rhesus macaques

ABSTRACTApproximately 12 rhesus macaques (Macaca mulatta) were introduced to the forests along the Silver River, central Florida, USA, between 2 introductions in the 1930s and 1940s to increase tourism; this land is now Silver Springs State Park (SSSP). By the mid‐1980s the population along the Silver River reached nearly 400 individuals. Approximately 1,000 animals were trapped and removed from 1984 to 2012 to reduce population growth and mitigate negative macaque‐human interactions. This practice was halted due to extensive public controversy, and consequently no population management has been implemented since 2012. To aid in informing management decisions related to rhesus macaques, we estimated the fall 2015 population size within SSSP, developed an age‐structured matrix model to estimate the population growth rate, and examined the efficacy of 4 management strategies to regulate this population, including culling (50% or 80% of subadults and adults) and sterilizing adult females (50% or 80% ≥3 years old). Our assessment suggested there were 176 macaques among 5 social groups within SSSP in fall 2015. We estimated this population was growing and will likely double in size by 2022 without management intervention. Management actions designed to eradicate the macaque population would be most effective by removing ≥50% of subadults and adults at least biennially. The population could be reduced to about a third of the fall 2015 size by sterilizing ≥50% of adult females annually or ≥80% biennially. The rhesus macaque population extends outside of our study site, and thus our results are a proxy for management implications in the region. Managers tasked with rhesus macaque management must carefully weigh the trade‐offs of these options in future management of this charismatic, invasive species. © 2018 The Wildlife Society.

Developmental shifts in social cognition: socio-emotional biases across the lifespan in rhesus monkeys

Humans exhibit a suite of developmental changes in social cognition across the lifespan. To what extent are these developmental patterns unique? We first review several social domains in which humans undergo critical ontogenetic changes in socio-cognitive processing, including social attention and theory of mind. We then examine whether one human developmental transition—a shift in socio-emotional preferences—also occurs in non-human primates. Specifically, we experimentally measured socio-emotional processing in a large population of rhesus macaques (Macaca mulatta) ranging from infancy to old age. We tested whether macaques, like humans, also exhibited developmental shifts from a negativity bias at younger ages, indicating preferential attention to negative socio-emotional stimuli, to a positivity bias at older ages. We first assessed monkeys’ (n = 337) responses to negative socio-emotional stimuli by comparing their duration of looking towards photos of negative conspecific signals (threat displays) versus matched neutral expressions. In contrast to the pattern observed in humans, we found that older monkeys were more attentive to negative emotional stimuli than were younger monkeys. In a second study, we used the same method to examine monkeys’ (n = 132) attention to positive (affiliative displays) versus matched neutral expressions. Monkeys did not exhibit an overall preference for positive stimuli, nor major age-related changes in their attention. These results indicate that while monkeys show robust ontogenetic shifts in social preferences, they differ from humans by exhibiting an increasing negativity bias with age. Studies of comparative cognitive development can therefore provide insight into the evolutionary origins of human socio-cognitive development. Humans are characterized by complex and flexible social behavior. Understanding the proximate psychological mechanisms and developmental processes that underpin these social behaviors can shed light on the evolutionary history of our species. We used a comparative developmental approach to identify whether a key component of human social cognition, responses to emotionally-charged social stimuli, are shared with other primates. Humans exhibit important shifts in this aspect of our social cognition: younger individuals attend more to negative stimuli, whereas older adults tend to focus on positive information. These shifts are thought to appropriately tailor our age-dependent social goals. We found that, unlike humans, rhesus monkeys show an increasing negativity bias with age. By examining primate cognition across the lifespan, this work can help disentangle how complex forms of social behavior emerge across species.

Which male and female characteristics influence the probability of extragroup paternities in rhesus macaques, Macaca mulatta?

Extragroup paternity (EGP) is found across a wide range of species and may entail reproductive benefits, but may also entail costs to both sexes. While population and group parameters affecting the degree of EGPs are relatively well established, less is known about the individual characteristics that make males and females engage in alternative reproductive tactics such as EGP. Applying a combination of long-term demographic and genetic data from the rhesus macaque population of Cayo Santiago (Puerto Rico, U.S.A.), we investigate which male and female characteristics influence the probability of EGP to better understand the circumstances that shape the distribution and occurrence of EGP. Our results show that, against our expectations, higher-ranking females were more likely to produce EGP offspring than lower- ranking females. The probability of producing extragroup offspring was not significantly related to female or male age, male tenure or previous reproductive success. Furthermore, genetic relatedness between the parents did not affect the production of extragroup offspring, but extragroup offspring were more frequently produced early rather than late in a given mating season. Altogether, our analysis suggests that individual attributes and seasonal aspects create different opportunities and preferences for engaging in EGP as an alternative reproductive tactic. The observed patterns of EGP in rhesus macaques appear to be consistent with female mate choice for genetic benefits, which needs to be confirmed in future studies.

Mismatch repair gene mutations lead to lynch syndrome colorectal cancer in rhesus macaques.

Colorectal cancer accounts for a substantial number of deaths each year worldwide. Lynch Syndrome is a genetic form of colorectal cancer (CRC) caused by inherited mutations in DNA mismatch repair (MMR) genes. Although researchers have developed mouse models of Lynch Syndrome through targeted mutagenesis of MMR genes, the tumors that result differ in important ways from those in Lynch Syndrome patients. We identified 60 cases of CRC in rhesus macaques (Macaca mulatta) at our facility since 2001. The tumors occur at the ileocecal junction, cecum and proximal colon and display clinicopathologic features similar to human Lynch Syndrome. We conducted immunohistochemical analysis of CRC tumors from several rhesus macaques, finding they frequently lack expression of MLH1 and PMS2 proteins, both critical MMR proteins involved in Lynch Syndrome. We also found that most macaque cases we tested exhibit microsatellite instability, a defining feature of Lynch Syndrome. Whole genome sequencing of rhesus macaque CRC cases identified mutations in MLH1 and/or MSH6 that are predicted to disrupt protein function. We conclude that this population of rhesus macaques constitutes a spontaneous model of Lynch Syndrome, matching the human disease in several significant characteristics, including genetic risk factors that parallel human Lynch Syndrome.

MLH1-rheMac hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques

Over the past two decades, 33 cases of colonic adenocarcinomas have been diagnosed in rhesus macaques (Macaca mulatta) at the nonhuman primate colony of the Keeling Center for Comparative Medicine and Research at The University of Texas MD Anderson Cancer Center. The distinctive feature in these cases, based on PET/computed tomography (CT) imaging, was the presence of two or three tumor lesions in different locations, including proximal to the ileocecal juncture, proximal to the hepatic flexure, and/or in the sigmoid colon. These colon carcinoma lesions selectively accumulated [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fluoroacetate ([18F]FACE) at high levels, reflecting elevated carbohydrate and fatty acid metabolism in these tumors. In contrast, the accumulation of [18F]fluorothymidine ([18F]FLT) was less significant, reflecting slow proliferative activity in these tumors. The diagnoses of colon carcinomas were confirmed by endoscopy. The expression of MLH1, MSH2, and MSH6 proteins and the degree of microsatellite instability (MSI) was assessed in colon carcinomas. The loss of MLH1 protein expression was observed in all tumors and was associated with a deletion mutation in the MLH1 promoter region and/or multiple single-nucleotide polymorphism (SNP) mutations in the MLH1 gene. All tumors exhibited various degrees of MSI. The pedigree analysis of this rhesus macaque population revealed several clusters of affected animals related to each other over several generations, suggesting an autosomal dominant transmission of susceptibility for colon cancer. The newly discovered hereditary nonpolyposis colorectal cancer syndrome in rhesus macaques, termed MLH1-rheMac, may serve as a model for development of novel approaches to diagnosis and therapy of Lynch syndrome in humans.

Characterization of the Gut Microbiota in Six Geographical Populations of Chinese Rhesus Macaques (Macaca mulatta), Implying an Adaptation to High-Altitude Environment.

Knowledge about the impact of different geographical environments on rhesus macaque gut microbiota is limited. In this study, we compared the characteristics of gut microbiota in six different Chinese rhesus macaque populations, including Hainan, Nanning, Guizhou, Xichang, Jianchuan and Tibet. Through the composition analysis of operational taxonomic units (OTUs), we found that there were significant differences in the abundance of core overlapping OTUs in the six Chinese groups. Specifically, the Tibet population exhibited the highest gut microbial diversity and the most unique OTUs. Statistically significant differences in the composition of gut microbiota among the six groups at phylum and family level were evident. Specifically, Tibet had higher abundances of Firmicutes and lower abundances of Bacteroidetes than the other geographical groups, and the higher abundance of Firmicutes in the Tibetan group was mainly caused by a significant increase in the family Ruminococcaceae and Christensenellaceae. Phylogenetic investigation of communities by reconstruction of unobserved state analysis showed that the enrichment ratio for environmental information processing and organismal systems was the highest in the Tibet population. Additionally, our results suggested that in the adaptation process of rhesus macaques to different geographical environments, the abundance of the core common flora of the intestinal microbes had undergone varying degree of change and produced new and unique flora, both of which helped to reshape the gut microbiota of rhesus macaques. In particular, this change was more obvious for animals in the high-altitude environments.

Alpha male status and availability of conceptive females are associated with high glucocorticoid concentrations in high-ranking male rhesus macaques (Macaca mulatta) during the mating season

The relationship between male mating opportunities, stress, and glucocorticoid concentrations is complicated by the fact that physiological stress and glucocorticoid concentrations can be influenced by dominance rank, group size, and the stability of the male dominance hierarchy, along with ecological factors. We studied the three highest-ranking males in nine different social groups within the same free-ranging population of rhesus macaques on Cayo Santiago, Puerto Rico, during the mating season, to examine variation in glucocorticoid concentrations in relation to number of females that conceived each month, alpha status, number of adult males in a group, and male rank hierarchy stability. We found that glucocorticoid concentrations were highest in the early mating season period when more females conceived in each group and declined linearly as the mating season progressed and the number of conceptive females decreased. Alpha males had significantly higher mean monthly glucocorticoid concentrations than other high-ranking males throughout the study period. Male age, number of adult males in a group, and hierarchy stability were not significantly associated with glucocorticoid concentrations. Our findings suggest that alpha males may experience significantly higher levels of physiological stress than their immediate subordinates and that this stress coincides with the period of the mating season when most conceptions occur.

SNP-based genetic characterization of the Tulane National Primate Research Center's conventional and specific pathogen-free rhesus macaque (Macaca mulatta) populations.

The rhesus macaque is an important biomedical model organism, and the Tulane National Primate Research Center (TNPRC) has one of the largest rhesus macaque breeding colonies in the United States. SNP profiles from 3266 rhesus macaques were used to examine the TNPRC colony genetic composition over time and across conventional or SPF animals of Chinese and Indian ancestry. Chinese origin animals were the least genetically diverse and the most inbred; however, since their derivation from their conventional forebearers, neither the Chinese nor the Indian SPF animals exhibit any significant loss of genetic diversity or differentiation. The TNPRC colony managers have successfully minimized loss in genetic variation across generations. Although founder effects and bottlenecks among the Indian animals have been successfully curtailed, the Chinese subpopulation still show some influences from these events.