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An obituary for Kenneth Alan Bennett, professor of anthropology at the University of Wisconsin-Madison in Madison, Wisconsin, is presented.

An introduction is presented in which the editors discuss various reports within the issue on topics including the anthropology of informed consent, the perceptions of people on biosecurity, and anthropology of secrecy.

Habitat loss and fragmentation are known to restrict the movements of primates, including their ability to expand their home ranges. These effects are especially strong at high densities, where home range overlap can result in high rates of agonistic intergroup encounters over range defense. We investigated habitat use and range defense in a population of northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural – Feliciano Miguel Abdala, in Minas Gerais, Brazil from August 2010 to July 2013. The four groups in this isolated population used 878 ha of forest, with home ranges exhibiting high interannual fidelity in location and low intergroup overlap. Core areas represented 13–29% of the respective home ranges and, except for one group, showed only moderate to low interannual fidelity in successive years. Of 130 intergroup encounters recorded in 2010–2011, significantly more occurred in core areas that overlapped with the range of another group than in areas of home range overlap or areas used exclusively by one group. Daily path lengths of the one group used in assessing range defensibility varied little (1075–1132 m) across years and relative to home range diameter did not meet the criteria for defensibility. However, the occurrence of independent subgroups, combined with a mean monthly detection distance of 242 m, provides strong evidence of range defensibility. These findings point to the importance of fission–fusion dynamics for intergroup range defense, particularly in primates living at high densities in fragmented habitats. [ABSTRACT FROM AUTHOR]

The article comments on the paper "The Human Community As a Primate Society," by Lars Rodseth, Richard W. Wrangham, Alisa M. Harrigan and Barbara B. Smuts in this issue. It is pointed out that primary contributions of Rodseth and colleagues are their comparative insights, their focus on common variables, and their identification of theoretically significant continuities and discontinuities.

The size and composition of primate groups affect dispersal and reproductive opportunities, and thus have implications for the conservation and management of endangered species. Group fissions that increase dispersal options can reduce close inbreeding, particularly in small, isolated populations that are candidates for translocation and other forms of management. While the impact of group size on permanent group fissions has been well documented in matrilocal societies, less is known about the process of permanent fission in patrilocal primates. Here, we use social network analyses of four years of scan-sample data (2011–2014) to retrospectively investigate whether membership in a newly fissioned group of northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural – Feliciano Miguel Abdala, Caratinga, Minas Gerais, Brazil, could be predicted from prior social relationships. Modularity metrics indicated the start of the Matão group fission during the 2012–2013 mating season, with a distinct subgroup of individuals that formed the new Nancys group being evident. Dyadic associations were significantly stronger and eigenvector centrality values were significantly higher among the individuals that formed the Nancys group than among those that remained in the Matão group. One mother and her four adult sons were among the founders of the Nancys group, but other mother-adult son families did not fission together. Our analyses add to the literature on permanent fissions in patrilocal societies. They also suggest that the modularity metric of social network analyses can be useful in identifying the best timing for implementing management programs that take social preferences into account. Such considerations can contribute to informed decisions about translocations, reintroductions, and the rehabilitation of groups or subgroups in the conservation management of endangered primates such as muriquis. [ABSTRACT FROM AUTHOR]

Primate research and conservation may inadvertently reproduce neocolonial dynamics when primatologists from affluent, imperialist nations conduct studies in primate habitat countries. Here, we consider how interrogating the positionality of both foreign researchers and range-country collaborators can strengthen primatology. Such consideration may help us to better understand where each member of the collaboration is coming from, both figuratively and literally, and how those situated perceptions shape the research process. Centering the perspectives of the range-country collaborators, whose perspectives are infrequently voiced within the primatology literature, may illuminate challenges in cross-cultural communication and imbalances of knowledge and power. Here, we explore how positionality shapes collaborative research through the narratives of two foreign/range-country collaborator teams doing primate research and conservation in Africa and South America. Our goal is to provide examples that consider the positionalities of range-country collaborators relative to both foreign researchers and local community members, and that serve as models for primate researchers as they consider their own research teams' positionalities. These narratives highlight how prioritizing the perspectives of range-country and local collaborators when they differ from those of foreign collaborators can strengthen future research and conservation efforts. [ABSTRACT FROM AUTHOR]

We investigated demographic changes in three primate species (Alouatta guariba, Sapajus nigritus, and Callithrix flaviceps) at the Reserva Particular do Patrimônio Natural–Feliciano Miguel Abdala, Caratinga, Minas Gerais, Brazil, following a yellow fever outbreak (YFO) by comparing their population sizes before (2015) and after the outbreak (2017–2018), and by monitoring the size, composition, and reproductive status of groups from 2017 to 2021. Comparisons of pre‐ and post‐YFO census data indicate the A. guariba population declined by 86.6%, from an estimated minimum of 522 individuals to 70 individuals. However, by October 2021, the population had grown to at least 86 individuals, with an adult sex ratio (N = 53) that was female‐biased (0.61). Eleven of the 13 groups being monitored systematically were reproductively active with high survivorship to 12 months of age. S. nigritus declined by 40%, from 377 to 226 individuals. The sex ratio of 33 adult S. nigritus is also female‐biased (0.71), and at least 8 of 15 groups being monitored are reproductively active. C. flaviceps declined by 80%, from 85 individuals to the 15–17 individuals observed from 2017 to 2021. The female‐biased adult sex ratio and presence of infants and juveniles in the A. guariba and S. nigritus groups are encouraging signs, but there is still great concern, especially for C. flaviceps. Continued monitoring of the demographics of these primates is needed as their persistence appears to still be at risk. Research highlights: This study documented an unprecedent decline in three endemic primate species following a severe yellow fever outbreak in the Brazilian Atlantic Forest.Adult female biased sex ratios and reproductive activity suggest at least two species may be recovering from the drastic demographic changes. [ABSTRACT FROM AUTHOR]

The article discusses the population recovery of the buffy-headed marmoset, a Critically Endangered species, in the Private Natural Heritage Reserve–Feliciano Miguel Abdala in Brazil. The population of the marmoset declined by over 80% due to a yellow fever outbreak, but recent observations suggest that the population may be recovering. The study counted 35 individuals in total, compared to 17 individuals in previous years. The increase in population is promising for the long-term recovery of the species, although threats such as competition with invasive species and hybridization still persist. [Extracted from the article]

We investigated the genetic structure and kinship patterns of black howler monkeys ( Alouatta pigra) at Palenque National Park, Mexico. Fecal samples from 49 individuals residing in eight social groups were successfully genotyped for 19 polymorphic microsatellite markers known to be variable in other ateline primates. Overall, genetic diversity was low ( Ho = 0.588) with an average of 4.2 alleles per loci (range = 2-8). We found that intergroup genetic variation among adults was relatively high (mean between-group FST = 0.119), largely due to the genetic divergence of one study group from the others. Intragroup kinship patterns showed that in most social groups, either adult males, adult females, or individuals of both sexes resided with same-sexed adult kin, suggesting that some black howler males and females may not disperse from their natal group or may disperse with related individuals. Of the six sampled immigrant males, two males joined established groups by themselves, and four males formed two pairs that each took over the social group they joined after evicting the resident males. Males in both these coalitions were genetically closely related, while the two solitary immigrants were not closely related to any of the resident males present in the group they joined. Am. J. Primatol. 74:948-957, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We investigated the social relationships among adult females in two multimale-multifemale groups of black howler monkeys Alouatta pigra during a 14-month study in Palenque National Park, Mexico. Based on over 900 focal hours and over 5400 scan samples recording neighboring group members, we found that females very rarely engaged in agonistic interactions and no dominance hierarchy could be discerned. Relationships among resident females were primarily affiliative, but females of one study group spent a higher proportion of time in close proximity and engaged in affiliative interactions with one another at higher rates than females in the other study group. The strength of female relationships increased with the birth of an infant. Although no females immigrated during the study period, the temporary association of three extragroup females with our study groups implies that the social system of black howler monkeys is more dynamic than previously suggested. These findings suggest that female black howler monkeys behave more similarly to female red howler monkeys A. seniculus than to female mantled howler monkeys A. palliata [Current Zoology 57 (1): 1-7, 2011]. [ABSTRACT FROM AUTHOR]

We investigated whether sex differences in spatial dynamics correlate with rates of staccato and neigh vocalizations in northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural–Feliciano Miguel Abdala, Minas Gerais, Brazil. A total of 2,727 10 min focal subject samples were collected on 32 adult females and 31 adult males between April 2007 and March 2008. Compared with males, females spent a significantly lower proportion of their time in proximity to other group members and gave staccatos at significantly higher rates while feeding, resting, and traveling. Conversely, males emitted neigh vocalizations at significantly higher rates than females when feeding and resting only. Both sexes gave significantly more staccatos when feeding than when they were engaged in other activities, but their respective rates of neighs did not vary across activities. Both females and males emitted staccato vocalizations at significantly higher rates during times of the year when preferred foods were scarce, but no seasonal differences in the rates of neigh vocalizations were observed in either sex. Females and males showed a reduction in the number of neighbors following staccato vocalizations and an increase in the number of neighbors following neigh vocalizations. Our findings of sex differences in the rates of staccato and neigh vocalizations and the effects of these vocalizations on interindividual spacing are consistent with sex differences in spatial dynamics, and confirm the role of vocal communication in mediating spatial associations in this species. Am. J. Primatol. 72:122–128, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

We present data on the spread of terrestrial activities in one group of wild northern muriqui monkeys (Brachyteles hypoxanthus). Both males and females consumed fruit, drank, rested, traveled, and socialized terrestrially, but proportionately more males spent significantly more of their time on the ground than females, and females were more likely to engage in terrestrial activities when accompanied by males than when by themselves. Terrestrial activities occurred in both open and closed habitats where arboreal substrates were available and utilized by other individuals engaged in similar activities. Ecological and demographic factors may have stimulated the muriquis’ vertical niche expansion, but increases in the frequency and diversity of terrestrial activities, the high proportion of group members that engage in terrestriality, and its diffusion along male-biased social bonds are consistent with the development of a local terrestrial tradition similar to other types of traditions described in other primates. [Key words: terrestriality, ecology, predation, tradition] [ABSTRACT FROM AUTHOR]

This study tested the “challenge hypothesis” and rank-based predictions for temporal steroid production in male tufted capuchin monkeys, Cebus apella. Fecal samples (n = 209) collected from six wild males were analyzed for testosterone and cortisol concentration by enzyme immunoassay. The temporal pattern in male steroid production was compared to female sexual activity and rates of male aggression. The top-ranking adult male did not differ from other adult males in testosterone or cortisol concentration. Mean adult testosterone was significantly higher than mean subadult testosterone throughout the year. There was a clear elevation of testosterone and cortisol in both adult and subadult males during the peak of adult female sexual activity after the birth season. In fact, the magnitude of increase in testosterone was higher than predicted for a species with low male–male aggression. However, there was no difference between nonbreeding baseline testosterone levels during the birth season, and the “breeding” baseline of testosterone in males found during asynchronous female sexual activity. Of all behavioral indices examined, the distribution of female-maintained consortships was the best predictor of mean adult male testosterone concentrations. Although in many species, elevated testosterone coincides with increased male–male aggression, in the present study, the sustained high-magnitude increase in steroids during the peak of adult female sexual activity was associated with a relatively low rate of male–male intragroup aggression. [Copyright &y& Elsevier]

We examined the relationship between food patch size and feeding party size with comparative data from two populations of muriquis ( Brachyteles arachnoides) in the 37,797-ha forest at the Parque Estadual de Carlos Botelho (PECB), São Paulo, and the 800-ha forest at the Estação Biológica de Caratinga (EBC), Minas Gerais. Precipitation was more abundant and less seasonal at PECB than EBC, and the density of large trees (>25.0 cm) was higher at PECB (206 ha [sup -1] ) than at EBC (132 ha [sup -1] ). At both sites, the size of feeding parties is positively related to the size of food patches. As predicted, food patches at PECB are significantly larger than those at EBC for both fruit and leaf sources. Contrary to expectations, feeding parties were larger at EBC than PECB. The higher population density of muriquis and sympatric primates at EBC may make large associations more advantageous to these muriquis than to muriquis living at lower population densities in PECB. [ABSTRACT FROM AUTHOR]

Primate offspring often depend on their mothers well beyond the age of weaning, and offspring that experience maternal death in early life can suffer substantial reductions in fitness across the life span. Here, we leverage data from eight wild primate populations (seven species) to examine two underappreciated pathways linking early maternal death and offspring fitness that are distinct from direct effects of orphaning on offspring survival. First, we show that, for five of the seven species, offspring face reduced survival during the years immediately preceding maternal death, while the mother is still alive. Second, we identify an intergenerational effect of early maternal loss in three species (muriquis, baboons, and blue monkeys), such that early maternal death experienced in one generation leads to reduced offspring survival in the next. Our results have important implications for the evolution of slow life histories in primates, as they suggest that maternal condition and survival are more important for offspring fitness than previously realized. [ABSTRACT FROM AUTHOR]

Habitat fragmentation due to human activities is one of the principal threats to all primates and is particularly so for arboreal platyrrhines. Its impact has been extreme in the Brazilian Atlantic forest, where most primate populations have been severely reduced in numbers and their distributions restricted, resulting in low probabilities of long-term persistence. One of the most severely affected species is the northern muriqui (Brachyteles hypoxanthus), which today has fewer than 1,000 individuals distributed over only a dozen populations and is considered to be Critically Endangered. Most of these populations are isolated and smaller than 50 individuals, including the population inhabiting the Sossego Forest in Simonésia, Minas Gerais. With fewer than 30 individuals associating in one social group, the Sossego muriqui population is doomed to extinction unless emergency management measures are implemented to protect it. We monitored the demography of the Sossego muriquis to evaluate the impacts of the introduction of a reproductive-aged female that was translocated into this population in December 2006. Data were collected on all individuals, identifiable from their natural markings, during 3 to 12 monthly surveys conducted each year from July 2012 to June 2020. They revealed that the population grew from 32 individuals in July 2012 to a peak of 38 in September 2015, but then declined to a low of 22 individuals in September 2017, coinciding with a yellow fever outbreak in the region. As of June 2020, there were 24 individuals present. Four of the surviving individuals were the translocated female and three of her five offspring. One of her daughters was confirmed to have emigrated to another forest fragment and a second daughter has not been seen since March 2019 and is suspected to have emigrated. During the eight years of monitoring, we recorded 17 births (11 females and six males) and 25 disappearances involving 17 females, including the female confirmed to have dispersed, and eight males. Our results emphasize the risks of demographic stochasticity in small, isolated populations. The confirmed emigration of one dispersal-aged female that failed to locate a group to join, and the absence of any immigrants, call attention to the demographic implications of translocation as a potential conservation tool for small, isolated populations of species such as the northern muriqui in which female dispersal and male philopatry are typical. [ABSTRACT FROM AUTHOR]

Citizen Science (CS) is a process that engages members of the public in the collection and interpretation of scientific data in collaboration with scientists. It is especially useful for monitoring biodiversity over extended periods and at larger scales than most researchers can cover themselves. Here we present preliminary insights from a project initiated to evaluate the potential of a systematic CS program to monitor primates in small fragments of Atlantic Forest surrounding the Reserva Particular de Patrimônio Natural Feliciano Miguel Abdala (RPPN-FMA), in Caratinga, Minas Gerais, Brazil. This region was near the center of a severe yellow fever outbreak that peaked in late 2016 and early 2017, which coincided with steep declines in the known populations of the four species of primates that occur sympatrically in the RPPN-FMA (Alouatta guariba, Brachyteles hypoxanthus, Callithrix flaviceps, and Sapajus nigritus). Nothing, however, was known about the status of these species in the surrounding forest fragments. To gain rapid insights into the status of primates in these fragments and at the same time to assess the feasibility of developing a more systematic CS program in the future, we visited 54 landowners within 6 km of the reserve, 49 of which agreed to participate by sharing their perceptions of primate presence or absence before and after the yellow fever outbreak, and in the subsequent potential recovery period. Consistent with the decline in primate populations in the RPPN-FMA and another region in southeastern Brazil, participants residing around the reserve perceived the greatest declines in populations of Alouatta and Callithrix, followed by Sapajus, with a comparatively small decline in Brachyteles. Participant perceptions, reflected in their monthly reports from June 2018 to June 2020, suggest that the presence of Alouatta (detected significantly more often by auditory cues) and Callithrix returned to pre-yellow fever levels, while that of Sapajus (detected more by visual cues) exceeded pre-yellow fever levels. The only species with seasonal variation in participant perceptions was Callithrix. Although systematic censuses are needed to calibrate participant reports, there is clear potential for the development of a more comprehensive CS program as part of conservation efforts to monitor primate species in this region. [ABSTRACT FROM AUTHOR]

Earth's rapidly changing climate creates a growing need to understand how demographic processes in natural populations are affected by climate variability, particularly among organisms threatened by extinction. Long-term, large-scale, and cross-taxon studies of vital rate variation in relation to climate variability can be particularly valuable because they can reveal environmental drivers that affect multiple species over extensive regions. Few such data exist for animals with slow life histories, particularly in the tropics, where climate variation over large-scale space is asynchronous. As our closest relatives, nonhuman primates are especially valuable as a resource to understand the roles of climate variability and climate change in human evolutionary history. Here, we provide the first comprehensive investigation of vital rate variation in relation to climate variability among wild primates. We ask whether primates are sensitive to global changes that are universal (e.g., higher temperature, large-scale climate oscillations) or whether they are more sensitive to global change effects that are local (e.g., more rain in some places), which would complicate predictions of how primates in general will respond to climate change. To address these questions, we use a database of long-term life-history data for natural populations of seven primate species that have been studied for 29-52 years to investigate associations between vital rate variation, local climate variability, and global climate oscillations. Associations between vital rates and climate variability varied among species and depended on the time windows considered, highlighting the importance of temporal scale in detection of such effects. We found strong climate signals in the fertility rates of three species. However, survival, which has a greater impact on population growth, was little affected by climate variability. Thus, we found evidence for demographic buffering of life histories, but also evidence of mechanisms by which climate change could affect the fates of wild primates. [ABSTRACT FROM AUTHOR]

Dramatic increases in human populations and per capita consumption, climate change, overexploitation of marine and freshwater resources, and deforestation have caused a litany of negative consequences for biodiversity. Such doom-and-gloom scenarios are widely known, frequently cited and frankly depressing. Although accurate assessments of threats have clear value for intervention planning, we believe there is also a need to reflect on successes. Such reflection provides balance to negative scenarios and may shift attention towards constructive, positive action. Here we use a systematic evaluation of 90 success stories provided by conservation scientists and practitioners to explore the characteristics of the projects perceived as being associated with success. Success was deemed to have occurred for 19.4% of the projects simply because an event had occurred (e.g. a law was passed) and for 36.1% of projects quantitative data indicated success (e.g. censuses demonstrated population increase). However, for most projects (63.9%) there was no evaluation and success was defined by the subjective opinion of the respondent. Conservation community members viewed successful projects most often as those being long-term (88%), small in spatial scale (52%), with a relatively low budget (68%), and involving a protectionist approach alone or in combination with another approach. These results highlight the subjectivity of definitions of success in conservation but also the characteristics of conservation efforts that the conservation community perceives as indicative of success. [ABSTRACT FROM AUTHOR]

Understanding variation in habitat quality, diet, and behavioral patterns is fundamental for the development of conservation strategies for threatened primates. From June-August 2013, we conducted a preliminary study of four northern sportive lemurs (Lepilemur septentrionalis)-Critically Endangered, solitary-foraging primates living in different forest fragments in Montagne des Français, Madagascar. We sought to obtain the first systematic data on the behavior and feeding ecology of this species in the wild, and identify potential differences in habitat characteristics. The four individuals in our study are estimated to represent approximately 8% of the known population of this species, about which very little else is known. Our data showed that the variety of plant parts consumed did not differ among the four individuals despite differences in habitat as determined by measures of anthropogenic disturbance, tree density, species diversity, total tree basal area, and presence of invasive species. The data suggest, however, that individuals in areas that suffer more anthropogenic threats spent slightly more time feeding, devoted a greater percentage of feeding time to fruit than to leaves, and had larger home ranges than those in areas with fewer different anthropogenic activities. Our results suggest that the ability of the northern sportive lemur to adjust its behavior under different environmental conditions may be beneficial to their ability to persist in degraded habitats. [ABSTRACT FROM AUTHOR]

Although the brown howler monkey (Alouatta clamitans) is a relatively well-studied Neotropical primate, its behavioral and dietary flexibility at the intra-population level remains poorly documented. This study presents data collected on the behavior and ecology of two closely located groups of brown howlers during the same period at the RPPN Feliciano Miguel Abdala in southeastern Brazil. One group occupied a primary valley habitat, henceforth the Valley Group (VG), and the other group occupied a regenerating hillside habitat, the Hill Group (HG). We hypothesized differences in the behavior and ecological parameters between these sympatric groups due to the predicted harsher conditions on the hillside, compared to the valley. We measured several habitat parameters within the home range of both groups and collected data on the activity budget, diet and day range lengths, from August to November 2005, between dawn and dusk. In total, behavioral data were collected for 26 (318 h) and 28 (308 h) sampling days for VG and HG, respectively. As we predicted, HG spent significantly more time feeding and consumed less fruit and more leaves than VG, consistent with our finding that the hillside habitat was of lower quality. However, HG also spent less time resting and more time travelling than VG, suggesting that the monkeys had to expend more time and energy to obtain high-energy foods, such as fruits and flowers that were more widely spaced in their hill habitat. Our results revealed that different locations in this forest vary in quality and raise the question of how different groups secure their home ranges. Fine-grained comparisons such as this are important to prioritize conservation and management areas within a reserve. [ABSTRACT FROM AUTHOR]

Although well documented in matrilocal primate species, group fission is still a poorly known phenomenon among patrilocal primates. In this paper we describe in detail a group fission event in the population of northern muriquis at the Reserva Particular do Patrimônio Natural-Feliciano Miguel Abdala in Caratinga, Minas Gerais, Brazil, using Social Network Analyses (SNA). Data on association patterns were collected during systematic observations from May 2002 to September 2005, and analyzed for dry (from May to October) and rainy seasons (from November to April). The fission process started with subgroup formation in the rainy season 2002-2003, and was completed by the dry season of 2003. By the dry season 2003, the parent group (Jaó) had fissioned to form a second mixed-sex group (Nadir) while a subgroup of males (MU) moved between the parent group and the newly established group. Before the Jaó group fission started (dry season 2002) and during its initial phases (rainy season 2002-2003), females that ultimately composed the daughter group (Nadir) were the most peripheral in the association network. In the rainy season 2002-2003, the median monthly ( N = 6) operational sex ratio (OSR) of Jaó group was 2.81. However, once Jaó females initiated the fissioning process to establish the Nadir group, the OSR was more favorable to males in the Nadir group than in the Jaó group. Our results suggest that males followed the females to escape an unfavorable OSR in their natal group. Am. J. Primatol. 76:529-538, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Women rarely give birth after ~45 y of age, and they experience the cessation of reproductive cycles, menopause, at ~50 y of age after a fertility decline lasting almost two decades. Such reproductive senescence in mid-lifespan is an evolutionary puzzle of enduring interest because it should be inherently disadvantageous. Furthermore, comparative data on reproductive senescence from other primates, or indeed other mammals, remains relatively rare. Here we carried out a unique detailed comparative study of reproductive senescence in seven species of nonhuman primates in natural populations, using long-term, individual-based data, and compared them to a population of humans experiencing natural fertility and mortality. In four of seven primate species we found that reproductive senescence occurred before death only in a small minority of individuals. In three primate species we found evidence of reproductive senescence that accelerated throughout adulthood; however, its initial rate was much lower than mortality, so that relatively few individuals experienced reproductive senescence before death. In contrast, the human population showed the predicted and well-known pattern in which reproductive senescence occurred before death for many women and its rate accelerated throughout adulthood. These results provide strong support for the hypothesis that reproductive senescence in midlife, although apparent in natural-fertility, natural-mortality populations of humans, is generally absent in other primates living in such populations. [ABSTRACT FROM AUTHOR]

Increased body size in B rachyteles has been regarded as an important evolutionary adaptation that allowed a greater reliance on leaves compared to other more frugivorous Atelidae, but its association with muriqui positional behavior and substrate use is still unknown. Here, we present original data on the feeding and resting postures of the northern muriqui ( B rachyteles hypoxanthus) and evaluate predictions about the relationships between body size, postural behavior, and substrate use derived from previously published data for other atelids (e.g. A louatta, A teles, and L agothrix). The study was undertaken from August 2002 to July 2003 on a large group of well-habituated muriquis inhabiting the Reserva Particular do Patrimônio Natural - Felíciano Miguel Abdala in Minas Gerais, Brazil. Consistent with our predictions, we found that B . hypoxanthus was highly suspensory during postural feeding (60.9%) and commonly used tail-hind limb suspension/horizontal tripod (38.0%) or tail-forelimb/hind limb suspension (21.4%). However, although tail-suspensory postures permitted the muriquis to use the terminal canopy and small-sized substrates, these areas were also accessed via tail-assisted above-branch postural behaviors involving multiple substrates. Unexpectedly, tail-suspensory postures were found to be frequently associated with large substrates, tree trunks, and the understory. We suggest that B rachyteles' ability to access food resources from all areas of a feeding tree and from tree crowns at different canopy levels may account for their ability to efficiently exploit food resources in seasonal disturbed forest fragments of the Brazilian Atlantic Forest today. Am. J. Primatol. 75:74-87, 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Analyses of spatial relationships and social interactions provide insights into the social structure of animal societies and the ways in which social preferences among and between dyads affect higher order social relationships. In this paper we describe the patterns of spatial associations and social interactions among adult male northern muriquis in order to evaluate the dynamics of their social networks above the dyadic levels. Systematic observations were made on the 17 adult males present in a multi-male/multi-female group from April 2004 through February 2005, and in July 2005. Analyses of their spatial relationships identified two distinct male cliques; some adult males (called "N" males) were more connected to the females and immatures than other adult males ("MU" males), which were more connected to one another. Affiliative interactions were significantly higher among dyads belonging to the same clique than to different cliques. Although frequencies of dyadic agonistic interactions were similarly low among individuals within and between cliques, MU males appeared to be subordinate to N males. Nonetheless, there were no significant differences in the copulation rates estimated for MU males and N males. Mutual benefits of cooperation between MU and N cliques in intergroup encounters might explain their ongoing associations in the same mixed-sex group. [ABSTRACT FROM AUTHOR]

Social, ecological, and historical processes affect the genetic structure of primate populations, and therefore have key implications for the conservation of endangered species. The northern muriqui (Brachyteles hypoxanthus) is a critically endangered New World monkey and a flagship species for the conservation of the Atlantic Forest hotspot. Yet, like other neotropical primates, little is known about its population history and the genetic structure of remnant populations. We analyzed the mitochondrial DNA control region of 152 northern muriquis, or 17.6% of the 864 northern muriquis from 8 of the 12 known extant populations and found no evidence of phylogeographic partitions or past population shrinkage/ expansion. Bayesian and classic analyses show that this finding may be attributed to the joint contribution of female-biased dispersal, demographic stability, and a relatively large historic population size. Past population stability is consistent with a central Atlantic Forest Pleistocene refuge. In addition, the best scenario supported by an Approximate Bayesian Computation analysis, significant fixation indices (&PHgr;ST = 0.49, &PHgr;CT = 0.24), and population-specific haplotypes, coupled with the extirpation of intermediate populations, are indicative of a recent geographic structuring of genetic diversity during the Holocene. Genetic diversity is higher in populations living in larger areas (>2,000 hectares), but it is remarkably low in the species overall (&thgr; = 0.018). Three populations occurring in protected reserves and one fragmented population inhabiting private lands harbor 22 out of 23 haplotypes, most of which are population-exclusive, and therefore represent patchy repositories of the species' genetic diversity. We suggest that these populations be treated as discrete units for conservation management purposes. [ABSTRACT FROM AUTHOR]

Human senescence patterns--late onset of mortality increase, slow mortality acceleration, and exceptional longevity--are often described as unique in the animal world. Using an individual-based data set from longitudinal studies of wild populations of seven primate species, we show that contrary to assumptions of human uniqueness, human senescence falls within the primate continuum of aging; the tendency for males to have shorter life spans and higher age-specific mortality than females throughout much of adulthood is a common feature in many, but not all, primates; and the aging profiles of primate species do not reflect phylogenetic position. These findings suggest that mortality patterns in primates are shaped by local selective forces rather than phylogenetic history. [ABSTRACT FROM AUTHOR]

In a stochastic environment, long-term fitness can be influenced by variation, covariation, and serial correlation in vital rates (survival and fertility). Yet no study of an animal population has parsed the contributions of these three aspects of variability to long-term fitness. We do so using a unique database that includes complete life-history information for wild-living individuals of seven primate species that have been the subjects of long-term (22–45 years) behavioral studies. Overall, the estimated levels of vital rate variation had only minor effects on long-term fitness, and the effects of vital rate covariation and serial correlation were even weaker. To explore why, we compared estimated variances of adult survival in primates with values for other vertebrates in the literature and found that adult survival is significantly less variable in primates than it is in the other vertebrates. Finally, we tested the prediction that adult survival, because it more strongly influences fitness in a constant environment, will be less variable than newborn survival, and we found only mixed support for the prediction. Our results suggest that wild primates may be buffered against detrimental fitness effects of environmental stochasticity by their highly developed cognitive abilities, social networks, and broad, flexible diets. [ABSTRACT FROM AUTHOR]

We studied two multimale–multifemale groups of black howler monkeys (Alouatta pigra) during a 14-month study (June 2006–July 2007) in Palenque National Park, Mexico to evaluate the ways in which their sexual behavior changes across ovarian cycles. We analyzed 231 fecal samples, collected every 2.2±1.4 days from five females. For four females, estradiol and progesterone profiles revealed an average (±SE) cycle length of 18.3±1.4 days. Copulations occurred significantly more frequently during the periovulatory period (POP), defined as the estimated day of ovulation ±3 days (N=18). This was largely the result of cycling females soliciting sexual interactions during their POPs. Females directed their solicitations significantly more often toward “central” males of their group, who had close spatial associations with females at other times, compared with “noncentral” males, who did not associate closely with females. Central males rarely solicited sexual interactions, but instead monitored the females' reproductive status by sniffing their genitals, and maintained significantly closer proximity to females during their POPs, suggesting male mate guarding when conceptions are most likely to occur. Our findings indicate that the reproductive strategies of black howler central males and females coincide, highly skewing mating opportunities toward central males. Black howler females, however, occasionally choose to copulate with noncentral resident males or extra-group males during their POPs, undermining the ability of central males to monopolize all reproductive opportunities. Am. J. Primatol. 71:153–164, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Renewed interest in fission-fusion dynamics is due to the recognition that such dynamics may create unique challenges for social interaction and distinctive selective pressures acting on underlying communicative and cognitive abilities. New frameworks for integrating current knowledge on fission- fusion dynamics emerge from a fundamental rethinking of the term "fission-fusion" away from its current general use as a label for a particular modal type of social system (i.e., "fission-fusion societies"). Specifically, because the degree of spatial and temporal cohesion of group members varies both within and across taxa, any social system can be described in terms of the extent to which it expresses fission-fusion dynamics. This perspective has implications for socioecology, communication, cognitive demands, and human social evolution. [ABSTRACT FROM AUTHOR]

Maternal care of offspring is ubiquitous among primates, but its duration varies across species due to factors such as dispersal patterns and social dynamics, which influence opportunities for and potential benefits of maternal investment in older offspring, respectively. We examined mother-offspring associations in wild northern muriquis (Brachyteles hypoxanthus), in which males are philopatric, females typically disperse before puberty, and social relationships among and between males and females are egalitarian. Associations were systematically recorded between ten mothers, each with two–six offspring in the study group, and all group members from August 2003–May 2004 at the RPPN-Feliciano Miguel Abdala in Minas Gerais, Brazil. Infants of both sexes received similarly high percentages of their mothers' association time. Mothers without infants also maintained strong associations with their youngest juvenile sons. Mothers did not spend consistently more time associating with either juvenile or adult sons than daughters. Our finding of non-preferential associations between muriqui mothers and their older male offspring suggests that extended maternal investment in offspring may be of minimal value in their egalitarian society compared with its value for species living in hierarchical societies. Am. J. Primatol. 70:301–305, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Female northern muriquis (Brachyteles hypoxanthus) are known to engage in frequent copulations with multiple partners, a pattern that in other primates has been attributed to various functions such as confusing paternity, reducing male aggression, or ensuring fertilization. However, in some female primates, promiscuity is restricted to times when conceptions are unlikely. We investigated whether female northern muriquis might exhibit a similarly mixed strategy by examining their mating, social, and activity patterns during their conception cycles versus other times. Systematic behavioral data were collected during an 18-month period between August 2001 and February 2003 on 13 adult females in a well-studied group at the RPPN-Feliciano Miguel Abdala, Minas Gerais, Brazil. Females mated on an average of 12.5±7.9 days during the study period, and spent significantly less time resting and engaging in non-sexual social behaviors, and significantly more time in sexual behaviors on days that they copulated than on days they did not. Three of the eight females for which sufficient data were available copulated significantly more often with their spatially closest non-kin associates, and four of five females that could be analyzed copulated significantly more often with their most frequent non-kin embrace partners. Comparisons between conception and non-conception periods revealed no differences in female activity budgets or in either the number of copulations or the number of different mating partners per female. Our results suggest that some females mate preferentially with close associates and social partners, but there is no indication that females alter their behavior during the cycles in which they conceive. Am. J. Primatol. 69:766–776, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Many arboreal primates descend to the ground, a custom that may occur more frequently in disturbed habitats, and in the presence of researchers to whom the primates are habituated. In this paper, we describe opportunistic observations of ground use in two groups of northern muriquis (Brachyteles hypoxanthus) at the RPPN Feliciano Miguel Abdala, Minas Gerais, Brazil. Members of both groups were observed drinking, resting, feeding, playing, and traveling on the ground to different degrees, and variation in the levels of habituation of the two groups may be responsible for the differences in the distribution of their terrestrial activities. The potential increase in vulnerability to predation or disease owing to ground use has implications for the conservation of this critically endangered species. Am. J. Primatol. 69:706–712, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Urine, feces, and copulation frequency were collected from two captive muriqui females, Brachyteles arachnoides , at the Centro de Primatologia do Rio de Janeiro following the resumption of postpartum ovarian cycles. Fecal steroid profiles from seven wild muriqui females at the Estação Biologica de Caratinga, Minas Gerais, Brazil, were compared to the captive females to determine the approximate patterns of steroid excretion relative to the urinary LH peak. Hormonal profiles from one of the captive female muriquis revealed a discrete urinary LH peak. For this female, fecal progesterone increased on the same day as the urinary LH peak, while fecal estradiol increased 6 days later and urinary steroids increased 5 days later. For both captive females, the onset of fecal progesterone increase was preceded by the onset of copulations, which occurred during at least a 5-day period. The complete fecal hormonal profiles of the one captive female for which continuous data were available were similar to those found in wild muriqui monkeys, with the onset of an increase in sustained progesterone levels occurring several days prior to the onset of sustained estradiol increase. These patterns suggest that fecal progesterone may be excreted rapidly in this species. The onset of sustained increase in fecal progesterone levels, together with the consistent delay in the onset of the sustained increase in estradiol, may provide the best indicators of the periovulatory period for muriqui females. Am. J. Primatol. 42:311–321, 1997. © 1997 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The taxonomy of muriquis, the largest extant primates in the New World, is controversial. While some specialists argue for a monotypic genus (Brachyteles arachnoides), others favor a two‐species classification, splitting northern muriquis (Brachyteles hypoxanthus) from southern muriquis (B. arachnoides). This uncertainty affects how we study the differences between these highly endangered and charismatic primates, as well as the design of more effective conservation programs. To address this issue, between 2003 and 2017 we collected over 230 muriqui fecal samples across the genus' distribution in the Brazilian Atlantic Forest, extracted DNA from these samples, and sequenced 423 base pairs of the mitochondrial DNA (mtDNA) control region. Phylogenetic and species delimitation analyses of our sequence dataset robustly support two reciprocally monophyletic groups corresponding to northern and southern muriquis separated by an average 12.7% genetic distance. The phylogeographic break between these lineages seems to be associated with the Paraíba do Sul River and coincides with the transition between the north and south Atlantic Forest biogeographic zones. Published divergence estimates from whole mitochondrial genomes and nuclear loci date the split between northern and southern muriquis to the Early Pleistocene (ca. 2.0 mya), and our new mtDNA dataset places the coalescence time for each of these two clades near the last interglacial (ca. 120–80 kya). Our results, together with both phenotypic and ecological differences, support recognizing northern and southern muriquis as sister species that should be managed as distinct evolutionarily significant units. Given that only a few thousand muriquis remain in nature, it is imperative that conservation strategies are tailored to protect both species from extinction. Research Highlights: Phylogenetic analysis of mitochondrial DNA from "northern" and "southern" muriquis identifies these primates as falling into two reciprocally monophyletic lineages. These taxa also differ phenotypically, ecologically, and possibly behaviorally.While dated mitochondrial and nuclear DNA phylogenies suggested the divergence between the two Brachyteles species around the start of the Pleistocene (ca. 2.0 mya), the coalescence times for both the northern and southern lineages are much more recent (ca. 120–80 kya).Together, these data support the recognition and conservation management of northern and southern muriquis as distinct species. [ABSTRACT FROM AUTHOR]