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Madagascar is experiencing some of the most persistent and alarming rates of anthropogenic forest loss, threatening its endemic flora and fauna. Numerous factors contribute to this forest degradation and loss, but in Madagascar it is most often attributed to heavy human reliance on forest products for income and survival. Montagne des Français (MDF) is a forest in northern Madagascar and the last remaining home of the Critically Endangered northern sportive lemur (Lepilemur septentrionalis). We assessed the type and frequency of anthropogenic disturbances observed at MDF, as well as the forest loss and fragmentation in this region over six decades. To assess current conditions, we systematically recorded occurrences of anthropogenic disturbances in ten lemur home ranges and three trails over two field seasons (June to July 2016; February to May 2017). To assess historical landcover change, we analyzed six, classified, 30-m resolution forest cover maps from 1953, 1973, 1990, 2000, 2010 and 2014. We recorded a total of 1,412 human-caused disturbances of eight different types in about 15 ha. Felled trees were the most frequently observed disturbance, with Bonaramatsigny (Leucaena leucocephala) the most frequently felled species. Forest cover at MDF drastically decreased from 76% in 1953, to 24% in 2014. Our results indicate that human disturbances are widespread and pervasive, contributing to overall forest cover loss and fragmentation at MDF, which impact the quality, connectivity, and availability of habitat for endemic lemurs of this region. [ABSTRACT FROM AUTHOR]

Demographic data are essential to assessments of the status of endangered species. However, establishing an integrated monitoring program to obtain useful data on contemporary and future population trends requires both the identification of priority areas and populations and realistic evaluations of the kinds of data that can be obtained under different monitoring regimes. We analyzed all known populations of a critically endangered primate, the muriqui (genus: Brachyteles) using population size, genetic uniqueness, geographic importance (including potential importance in corridor programs) and implementability scores to define monitoring priorities. Our analyses revealed nine priority populations for the northern muriqui (B. hypoxanthus) and nine for the southern muriqui (B. arachnoides). In addition, we employed knowledge of muriqui developmental and life history characteristics to define the minimum monitoring intensity needed to evaluate demographic trends along a continuum ranging from simple descriptive changes in population size to predictions of population changes derived from individual based life histories. Our study, stimulated by the Brazilian government’s National Action Plan for the Conservation of Muriquis, is fundamental to meeting the conservation goals for this genus, and also provides a model for defining priorities and methods for the implementation of integrated demographic monitoring programs for other endangered and critically endangered species of primates. [ABSTRACT FROM AUTHOR]

Comparative approaches to the evolution of primate social behavior have typically involved two distinct lines of inquiry. One has focused on phylogenetic analyses that treat social traits as static, species-specific characteristics; the other has focused on understanding the behavioral flexibility of particular populations or species in response to local ecological or demographic variables. Here, we combine these approaches by distinguishing between constraining traits such as dispersal regimes (male, female, or bi-sexual), which are relatively invariant, and responding traits such as grouping patterns (stable, fission-fusion, sometimes fission-fusion), which can reflect rapid adjustments to current conditions. Using long-term and cross-sectional data from 29 studies of 22 species of wild primates, we confirm that dispersal regime exhibits a strong phylogenetic signal in our sample. We then show that primate species with high variation in group size and adult sex ratios exhibit variability in grouping pattern (i.e., sometimes fission-fusion) with dispersal regime constraining the grouping response. When assessing demographic variation, we found a strong positive relationship between the variability in group size over time and the number of observation years, which further illustrates the importance of long-term demographic data to interpretations of social behavior. Our approach complements other comparative efforts to understand the role of behavioral flexibility by distinguishing between constraining and responding traits, and incorporating these distinctions into analyses of social states over evolutionary and ecological time. [ABSTRACT FROM AUTHOR]

Assessments of the status of endangered species have focused on population sizes, often without knowledge of demographic and behavioral processes underlying population recovery. We analyzed demographic data from a 28-year study of a critically endangered primate, the northern muriqui, to investigate possible changes in demographic rates as this population recovered from near extirpation. As the population increased from 60 to nearly 300 individuals, its growth rate declined due to increased mortality and male-biased birth sex ratios; the increased mortality was not uniform across ages and sexes, and there has been a recent increase in mortality of prime-aged males. If not for a concurrent increase in fertility rates, the population would have stabilized at 200 individuals instead of continuing to grow. The unexpected increase in fertility rates and in adult male mortality can be attributed to the muriquis' expansion of their habitat by spending more time on the ground. The demographic consequences of this behavioral shift must be incorporated into management tactics for this population and emphasize the importance of understanding demographic rates in the recovery of endangered species. [ABSTRACT FROM AUTHOR]

Levels of reproductive skew vary in wild primates living in multimale groups depending on the degree to which high-ranking males monopolize access to females. Still, the factors affecting paternity in egalitarian societies remain unexplored. We combine unique behavioral, life history, and genetic data to evaluate the distribution of paternity in the northern muriqui (Brachyteles hypoxanthus), a species known for its affiliative, nonhierarchical relationships. We genotyped 67 individuals (22 infants born over a 3-y period, their 21 mothers, and all 24 possible sires) at 17 microsatellite marker loci and assigned paternity to all infants. None of the 13 fathers were close maternal relatives of females with which they sired infants, and the most successful male sired a much lower percentage of infants (18%) than reported for the most successful males in other species. Our findings of inbreeding avoidance and low male reproductive skew are consistent with the muriqui's observed social and sexual behavior, but the long delay (=2.08 y) between the onset of male sexual behavior and the age at which males first sire young is unexpected. The allocation of paternity implicates individual male life histories and access to maternal kin as key factors influencing variation in paternal-and grandmaternal-fitness. The apparent importance of lifelong maternal investment in coresident sons resonates with other recent examinations of maternal influences on offspring reproduction. This importance also extends the implications of the "grandmother hypothesis" in human evolution to include the possible influence of mothers and other maternal kin on male reproductive success in patrilocal societies. [ABSTRACT FROM AUTHOR]

Understanding the evolution of primate behavioral diversity requires multilevel approaches that encompass individuals, populations, and the effects of individuals and populations on each other. At one level are analyses of individual behavior patterns under different ecological and demographic conditions. At another level are the effects of individual behavior on the demography and genetics of local populations, which in turn shape the behavior and biology of their individual members. Multilevel studies across populations and over time provide insights into the range of behavioral variation that particular species can express and are necessary for distinguishing the species-specific behavior patterns on which evolutionary comparisons are based. These studies therefore provide the insights necessary to incorporate intraspecific variation into comparative models. [ABSTRACT FROM AUTHOR]

Advances in our understanding of primate life histories and dispersal patterns provide insights into the ways in which facultative responses to local ecological and demographic conditions are mediated by phylogenetic constraints. The long life spans characteristic of primates provide the necessary conditions for overlapping generations of related individuals to maintain extended kin bonds. Dispersal regimes dictate the opportunities for biological kin to interact with one another and define the range of potential reproductive and social partners within and beyond their natal groups. Dispersal patterns also affect variation in components of life histories such as female age at first reproduction reproductive rates, and trade-offs between investment in current vs. future offspring and extended kin. Understanding these dynamics has important implications for assessing the viability of small populations and the ability of different primates to adapt. [ABSTRACT FROM AUTHOR]

Nonhuman primates occupy a special niche in anthropology because of the comparative insights into humans they provide. Initial anthropological interest in primates targeted the apes for their close phylogenetic relationships with humans, and the semiterrestrial Old World monkeys for their ecological similarities with hominids adapting to life on the ground. From the earliest anecdotal reports of tool use and hunting to more contemporary quantitative analyses of local "cultural" traditions, nonhuman primates have challenged deep-rooted concepts of human uniqueness and redefined the boundaries between us and other animals. Yet, despite the long-standing influence of primate studies in anthropology, approaches to studying primates began diverging from those of earlier ethnographers. Advances in primatology, particularly during the 1990s, have included a much deeper understanding of how ecology, phylogeny, and demography affect behavior. Insights into intraspecific, population-level variation represent an important area of convergence between primatology, other areas of anthropology, and conservation biology. [ABSTRACT FROM AUTHOR]

Presents a study which investigated patterns of sociality among wild male northern muriquis to explore some of the possible ways in which within-group scramble competition might shape their social and mating strategies. Variation in the type and strength of affiliative relationships among same-sexed primates; Patterns of sociality and affiliation; Dyadic associations and affiliations.

Conservation funding is currently limited; cost‐effective conservation solutions are essential. We suggest that the thousands of field stations worldwide can play key roles at the frontline of biodiversity conservation and have high intrinsic value. We assessed field stations' conservation return on investment and explored the impact of COVID‐19. We surveyed leaders of field stations across tropical regions that host primate research; 157 field stations in 56 countries responded. Respondents reported improved habitat quality and reduced hunting rates at over 80% of field stations and lower operational costs per km2 than protected areas, yet half of those surveyed have less funding now than in 2019. Spatial analyses support field station presence as reducing deforestation. These "earth observatories" provide a high return on investment; we advocate for increased support of field station programs and for governments to support their vital conservation efforts by investing accordingly. [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]

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 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 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]

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]

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]

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]

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]

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]