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Strong, affiliative relationships are important across social mammals, and in many species, relationships between female kin form the basis of group life. Relationships are expected to be weaker in cases where females disperse or do not cooperatively defend resources. Mountain gorillas, Gorilla beringei beringei , seem to support this, as females can emigrate multiple times throughout their life and do not jointly defend the abundant vegetation they feed on. Unsurprisingly, mountain gorillas have been reported to form variable or weak relationships with other females and seemingly prioritize relationships with adult males. But prior studies may have misinterpreted relationships due to a focus on grooming and understandable limitations of small sample sizes and short study periods. Here, we examine proximity and grooming between 47 adult female mountain gorillas in five groups over 5–13 years. We analyse proximity data (2 m, 5 m) and grooming relationships between 366 individual dyads to determine (1) whether proximity and grooming relationships are preferential and (2) whether they endure across time. Most females formed at least one preferential 2 m and 5 m proximity relationship (43 of 47), which both lasted a mean of 2.1 years. Additionally, 3.6% of dyads (N = 13/366) formed enduring 2 m proximity preferences that exceeded 4 years, with the longest lasting at least 12 years. Maternal kin had the most enduring proximity and grooming relationships, although grooming was rare overall. The enduring proximity relationships between some female gorillas in our sample are similar in length to those of female yellow baboons, Papio cynocephalus , and male chimpanzees, Pan troglodytes , which are considered social bonds. Mountain gorillas provide a system in which factors influencing bonds can be better understood, and our study highlights a need to refine definitions of social bonds while potentially reassessing their evolutionary function. • We examined proximity (2 m, 5 m) and grooming in female mountain gorilla dyads. • Most females formed one long-term (2–12 years) preferential proximity relationship. • Proximity relationships were akin to social bonds in baboons and chimpanzees. • Maternal kin were more likely to have preferential 2 m proximity relationships. • Dispersal patterns may allow adult females to remain with maternal kin longer. [ABSTRACT FROM AUTHOR]

Wildlife plays an important role in the emergence of livestock diseases, and their movements can complicate disease management efforts. One of the most significant vector‐borne diseases of livestock worldwide is bovine babesiosis, spread by cattle fever ticks (CFTs; Rhipicephalus [=Boophilus] microplus and Rhipicephalus [=Boophilus] annulatus). Although CFTs were eradicated from the United States by 1943, bovine babesiosis and CFTs are prevalent in México. Recently, management of CFTs in the Texas–México region has been complicated by the presence of free‐ranging, exotic nilgai antelope (Boselaphus tragocamelus). Nilgai are abundant in this region and are competent hosts for CFTs. The goal of this study was to better understand nilgai movements and space use to inform CFT treatment strategies. We analyzed hourly locations from 40 GPS‐collared nilgai in Cameron County, TX, USA, from April 2019 to September 2020. We assigned each nilgai a movement behavior using the net squared displacement metric. We estimated nilgai home range sizes at different temporal scales (monthly, seasonally, and overall) using Brownian bridge movement models. We observed movement patterns consistent with residency (52.5%), seasonal movers (17.5%), dispersal (5%), and unclassified (25%). Resident nilgai had an average maximum axial distance of 7.8 km, while two young females made separate dispersal movements of about 40 km within a year. Overall, nilgai had large and highly variable home ranges: annual median home range estimate for females was 563 ha (range = 105–1545 ha), and for males, it was 937 ha (range = 221–1602 ha). Peak nilgai movements occurred during crepuscular hours, and median hourly movement for females was 57 m/h, and for males, it was 66 m/h. Nilgai home ranges and long‐distance movements have the potential to overlap multiple ranches, as the typical ranch size in South Texas ranges from 250 to 6000 ha. Resident nilgai were more likely to maintain local infestations of CFT. Dispersal events took place during peak tick season, demonstrating the potential for nilgai to aid in the spread of CFT. Understanding these behaviors will help the CFT Eradication Program develop more efficacious treatment strategies to treat infestations in nilgai. [ABSTRACT FROM AUTHOR]

Social interactions ultimately impact health and fitness in gregarious mammals. However, research focusing on the strength of affiliative interactions has primarily been conducted on female philopatric species. Gorillas provide an interesting counterpoint to previous research as females emigrate multiple times throughout their lives. We compare female–female association strength, duration and consistency in wild mountain (Gorilla beringei beringei) and western gorillas (Gorilla gorilla gorilla). Additionally, we examine whether the alpha male influences female association strength and if these associations are an artefact of both females concurrently in spatial proximity of the alpha male. In this between-species comparison, female gorillas had differentiated association patterns that were consistent on average for 2 years. The alpha males did not influence female association strength, with associations being similar in his presence or absence. Finally, we found more variability in association patterns among mountain gorillas with higher average association scores and higher proportion of 'preferred associates' than western gorillas. The rare dispersal pattern in the Gorilla genus may lead to greater flexibility in female association patterns than in species exhibiting female philopatry and strong kinship bonds. This may echo ancestral human society and provide new evidence to help us understand the evolution of modern human society. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'. [ABSTRACT FROM AUTHOR]

Abstract Wildlife plays an important role in the emergence of livestock diseases, and their movements can complicate disease management efforts. One of the most significant vector‐borne diseases of livestock worldwide is bovine babesiosis, spread by cattle fever ticks (CFTs; Rhipicephalus [=Boophilus] microplus and Rhipicephalus [=Boophilus] annulatus). Although CFTs were eradicated from the United States by 1943, bovine babesiosis and CFTs are prevalent in México. Recently, management of CFTs in the Texas–México region has been complicated by the presence of free‐ranging, exotic nilgai antelope (Boselaphus tragocamelus). Nilgai are abundant in this region and are competent hosts for CFTs. The goal of this study was to better understand nilgai movements and space use to inform CFT treatment strategies. We analyzed hourly locations from 40 GPS‐collared nilgai in Cameron County, TX, USA, from April 2019 to September 2020. We assigned each nilgai a movement behavior using the net squared displacement metric. We estimated nilgai home range sizes at different temporal scales (monthly, seasonally, and overall) using Brownian bridge movement models. We observed movement patterns consistent with residency (52.5%), seasonal movers (17.5%), dispersal (5%), and unclassified (25%). Resident nilgai had an average maximum axial distance of 7.8 km, while two young females made separate dispersal movements of about 40 km within a year. Overall, nilgai had large and highly variable home ranges: annual median home range estimate for females was 563 ha (range = 105–1545 ha), and for males, it was 937 ha (range = 221–1602 ha). Peak nilgai movements occurred during crepuscular hours, and median hourly movement for females was 57 m/h, and for males, it was 66 m/h. Nilgai home ranges and long‐distance movements have the potential to overlap multiple ranches, as the typical ranch size in South Texas ranges from 250 to 6000 ha. Resident nilgai were more likely to maintain local infestations of CFT. Dispersal events took place during peak tick season, demonstrating the potential for nilgai to aid in the spread of CFT. Understanding these behaviors will help the CFT Eradication Program develop more efficacious treatment strategies to treat infestations in nilgai.

Affiliative relationships are a hallmark of social relationships in gregarious mammals, but what drives variation of association patterns when kin are absent remains unknown. Gorillas, where females may disperse multiple times in their lives, provide an interesting counterpoint to female philopatric species to examine the factors influencing variation in association patterns. We examined demographic and social factors that may predict association patterns of female western ( Gorilla gorilla gorilla ; Loango, Gabon) and mountain gorillas ( Gorilla beringei beringei ; Bwindi, Uganda). We looked at dyadic and individual strength scores of social proximity (37 group-years). For individuals, high dominance rank increased association scores while newly emigrated females had lower scores than resident females. For dyads, higher mean dominance rank and both partners having a dependent infant increased association scores, whereas a partner being an immigrant decreased scores. Furthermore, time-matched analysis of birth and immigration events confirmed the temporal nature of these associations. Overall, female gorilla association patterns show flexibility in strength based on real-time contingencies, namely social and demographic traits. Association patterns in species with female secondary dispersal may be governed by homophily, like that of modern humans. Understanding female gorilla social structure can enhance our knowledge of the evolutionary origins of sociality.

Cooperative home range defense is common in primates, despite a collective action problem that arises when group members benefit from winning the intergroup encounter regardless of whether they participate. The costs associated with this collective action problem may be mitigated by residing in small groups, residing with kin, or by forming strong bonds with group members. The potential to decouple the effects of these variables provided an opportunity to investigate which of these three variables best explains coparticipation in intergroup encounters among adult and subadult female colobus at Boabeng‐Fiema, Ghana. Because males are often the main participants, we also investigated the relationship between female–female coparticipation and adult and subadult male participation. We collected intergroup behaviors from 94 adult and subadult individuals in eight groups during 1 year. We quantified female grooming bond strength and approach rates using focal samples. We classified female dyads as close kin (i.e., halfsiblings or more closely related) or nonkin based on partial pedigrees and genotypes generated from 17 STR loci. Female–female coparticipation was higher in dyads with stronger grooming bonds but was not associated with dyadic kinship, approach rate, or age class. Female coparticipation decreased with increasing female group size as expected if there is a collective action problem. Females coparticipated less in groups with more males and male intergroup aggression, possibly because there is less need for female–female cooperation if males are participating in the intergroup encounter. Females in smaller groups may not only benefit from increased female–female cooperation during intergroup encounters, they are also likely to reside with a higher‐quality alpha male, both of which may increase the likelihood of winning intergroup encounters. There may be strong selection for facultative female dispersal in populations like the Boabeng‐Fiema colobus in which small groups are associated with multiple benefits and cooperation is not affected by kinship. Research Highlights: Approximately half of the females in the Colobus vellerosus population at Boabeng‐Fiema disperse, often from larger to smaller groups.Joint intergroup aggression in female C. vellerosus was predicted by female group size, dyadic grooming bonds, male group size, and male intergroup aggression but not by female kinship or age.Our findings contrast with the theoretical expectations of females remaining philopatric and forming strong bonds with female kin to facilitate cooperation during intergroup encounters. [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]

Mothers are the most fundamental individuals for the survival and development of their immature offspring. Sex-biased dispersal has an effect on strong and long-lasting social bonding between mothers and their philopatric offspring. Nepotistic relationships are often seen in species with male-biased dispersal but less frequently in species with female-biased dispersal. Bonobos are unique among female-biased dispersal primates in that the females are codominant with males, exert influence on the mating opportunities of their mature sons, and tolerate each other regardless of relatedness. Few studies on bonobos have examined sex differences in social relationships between juveniles and their mothers, and how this relates to mother–son and female–female cooperative relationships amongst adults. We investigated whether the association index of juveniles with their mothers changed with age depending on the sex of the juveniles in parties of bonobos at Wamba, the Democratic Republic of the Congo. We found that female bonobos had decreased party associations with their mothers prior to their emigration from the natal group, while male bonobos maintained relatively high party associations with their mothers. These results indicate that sex differences that emerge during the juvenile period in bonobos in their spatial relationships with their mothers differ from previous findings on chimpanzees, spider monkeys, and muriquis, in which philopatric sons tend to spend less time in proximity to their mothers and disperse earlier than, or at a similar age to, daughters. The contrasts between bonobos and other primate species suggest that the high social status of female bonobos relative to that of males may facilitate the extension of maternal support for their philopatric sons, and that high tolerance among unrelated females may enable the spatial independence of daughters from their mothers at an earlier stage. [ABSTRACT FROM AUTHOR]

Relationships between females of different groups in female philopatric species are typically antagonistic, whereas those in female dispersing species can be more moderate. Such nonantagonistic relationships among females of neighboring groups may allow immigrant females to minimize dispersal costs by migrating into those groups, whereas the frequency of female migration among neighboring groups is little understood in female dispersing species. Bonobos (Pan paniscus) are a species in which females disperse and often show affinitive interactions between groups during intergroup encounters. We examined the frequency of female migration into neighboring groups in bonobos using genetic and demographic data. We studied 27 immigrant female bonobos in three neighboring groups at Wamba, Democratic Republic of the Congo. We estimated the frequency of female migration into neighboring groups using the following formula: the number of females that migrated into any neighboring group/the number of females that migrated into any nonnatal group. We estimated the number of females that migrated into any neighboring group using genetic evidence for female migration among the three groups, and the number of neighboring groups for the three groups. We estimated the number of females that migrated into any nonnatal group using the age of subject females, age of first birth, interbirth intervals, and mortality. The estimated frequency of female migration into any neighboring group was 60% (4.5/7.48). Our results suggest that female bonobos do not disperse far from their natal groups, which may be because they usually transfer between groups during intergroup encounters. [ABSTRACT FROM AUTHOR]

The mother-offspring relationship is paramount in most mammals and infant survival often depends on maternal investment. In species with prolonged periods of development or co-residence, mothers may continue to influence their offspring's outcomes beyond nutritional independence with benefits biased towards the philopatric sex. Chimpanzees (Pan troglodytes) are long-lived mammals with a protracted period of immaturity during which offspring continue to travel with their mothers. In contrast to most mammals, chimpanzees are also typically male philopatric. Here, we use over 50 years of demographic data from two communities in Gombe National Park, Tanzania, to examine the survival and longevity of both male and female chimpanzees that experienced maternal loss during three different age categories. Males who were orphaned between the ages of 0–4.99 years, 5–9.99 years, and 10–14.99 years all faced significantly lower survival than non-orphans and died earlier than expected. Females faced similarly reduced survival probabilities when orphaned between 0–4.99 and 5–9.99 years of age; however, females who experienced maternal loss between 10 and 14.99 years of age were no more likely to die than non-orphans. Females orphaned in this later age class also lived significantly longer beyond maternal loss than their male counterparts. As observed in other mammals, philopatric male chimpanzees may continue to benefit from their mother's ecological knowledge, whereas maternal influence on female offspring likely fades as they prepare to emigrate. These results emphasize how maternal influence on offspring outcomes can extend well beyond weaning, particularly for the philopatric sex. Significance statement: Mammalian mothers are crucial to their infant's survival and in species where offspring continue to live with their mothers after weaning, maternal influence may extend beyond dependence on mother's milk. While in most group-living mammals females remain in their natal group, chimpanzees typically display the opposite pattern with males residing alongside their mothers into adulthood. Using over 50 years of data on wild chimpanzees, we investigated the consequences of maternal loss both before and after weaning. We found that both males and females orphaned up to 10 years of age were less likely to survive than non-orphans; however, only males orphaned between 10 and 15 years also faced lower survival. These results emphasize how chimpanzee mothers continue to matter for offspring beyond infancy and provide novel data on reduced maternal influence on survival for daughters compared to sons. [ABSTRACT FROM AUTHOR]

It has been discussed in the literature that the presence of kin, particularly the presence of a women's own mother or her mother in law, may have fertility effects. We aimed to examine the effects of the presence of a woman's own or her husband's mother in the household on a woman's fertility in terms of number of children on a broad basis by analysing census data of over two million married women aged between 15 and 34 years from 14 countries worldwide. We find that with the exception of Iraq, across all countries, the majority of women live only with their spouse in the household. We further find that the presence of any mother in the household is invariably associated with a significantly lower number of children compared to women living only with their spouse. In addition, in most countries, a woman's number of children is lower if she lives with her own mother as compared to her husband's mother in the household. Number of children is nonlinearly associated with woman's age, the presence of any mother being related with an earlier start of childbearing but a shallower increase in number of children. We speculate that the presence of a mother in the household may slow down woman's reproduction, but also discuss alternative explanations.

Group living leads to competition for food between group members. Two types of intragroup food competition may occur: scramble competition, in which all group members use the same resource, such that feeding opportunities are equal for everyone; and contest competition, in which some group members monopolize resources through aggression and dominance. In species in which females disperse from the natal group and immigrate into other groups, immigrant females increase group size and thus possibly food competition. Under these circumstances, other females may use aggression to discourage new females from joining the group. We assessed the distribution of aggression, embraces, and kisses among female spider monkeys ( Ateles geoffroyi) in relation to group tenure. We recorded social interactions during 1688 10-min focal animal samples on 11 females in Santa Rosa, Costa Rica. We found that aggression was rare between long-term resident females and aggression rates were not higher during feeding than in other contexts, suggesting there was little contest competition. Long-term residents and less recently immigrant females showed higher aggression rates toward the most recent immigrants than toward other females, especially during the first months after a female immigrated, which coincided with the dry season. We did not find similar patterns for embrace and kiss. These results suggest that other females target aggression toward the most recent immigrants to reduce scramble competition. This finding suggests that group tenure should be included in socioecological models for species with female dispersal. [ABSTRACT FROM AUTHOR]

Male takeovers affect male tenure, female mate choice and ultimately, individual reproductive success in group-living primates. In social systems with female philopatry and high male reproductive skew, male takeovers largely determine female mate choice, whereas in species with female dispersal, females have the option of deserting a new male. We focused on a species with facultative female dispersal to investigate which factors promote female desertion of males after takeover, using 15 cases (12 for which we have complete data on the takeover process and the female dispersal outcome). These cases took place in nine groups of Colobus vellerosus between 2001 and 2013 at the Boabeng-Fiema Monkey Sanctuary, Ghana. Quick takeovers were usually achieved by single adult males and were never followed by female dispersal. Slow takeovers involved several males, and these takeovers were regularly accompanied by female emigration. Infant attacks and infanticide by males occurred during both kinds of takeovers, but females with dependent offspring never dispersed, regardless of whether their infant was attacked or killed by the new male(s). Subadult females, who were not constrained by the presence of infants, dispersed more often after slow takeovers than after quick takeovers. Whether female dispersal post-takeover is an expression of female mate choice, or occurs to avoid the social upheaval surrounding slow takeovers, remains to be investigated. Am. J. Primatol. 79:e22436, 2017. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives Primate social systems are remarkably diverse, and thus play a central role in understanding social evolution, including the biological origin of human societies. Although baboons have been prominently featured in this context, historically little was known about the westernmost member of the genus, the Guinea baboon ( Papio papio). Material and Methods Here, we summarize the findings from the first years of observations at the field site CRP Simenti in the Niokolo Koba National Park in Senegal. Results Guinea baboons reveal a nested multi-level social organization, with reproductive units comprising one 'primary' male, one to several females, young, and occasionally 'secondary' males at the base of the society. Three to five units form 'parties,' which team up with other parties to form a 'gang.' Different gangs have largely overlapping home ranges and agonistic interactions between different parties or gangs are rare. Some but not all strongly socially bonded males are highly related, and population genetic and behavioral evidence indicate female-biased dispersal. Females play an important role in intersexual bond formation and maintenance, and female tenure length varies between a few weeks to several years. Discussion While the social organization resembles that of hamadryas baboons ( P. hamadryas), the social structure differs considerably, specifically in terms of low male aggressiveness and female freedom. Despite substantial differences in social organization and social structure, the acoustic structure of Guinea baboon vocalizations does not differ substantially from that of other baboon taxa. With its multi-level organization, stable bonds between males and females, as well as a high-degree of male-male cooperation and tolerance, Guinea baboons constitute an intriguing model for reconstructing human social evolution. [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].

Dispersal behavior in white-tailed deer ( Odocoileus virginianus) predominantly occurs in 1-year-old males; however, females of the same age also disperse. The timing of female dispersal during fawning season and low dispersal rates suggest that competition for mates and reduced inbreeding are not ultimate causes of female dispersal, as suggested for males. We proposed that female dispersal is the result of competition for space when pregnant females seek to isolate themselves before and after parturition. To test this hypothesis, we conducted a meta-analysis of female dispersal rates from 12 populations of white-tailed deer and predicted dispersal rate and distance were positively related to deer density. We found a positive relationship between dispersal rate and deer per forested km2 and between dispersal distance and deer per forested km2. These results are consistent with the hypothesis that female dispersal is density-dependent and caused by the exclusion of subordinate 1-year-olds as adult females seek isolation before and after parturition. [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]

Natal dispersal is a milestone in an animal's life history, but its timing in developmental trajectories may differ between species. Although the two Pan species exhibit a similar pattern of female-biased dispersal, female bonobos (P. paniscus) leave their natal groups at an earlier age than female chimpanzees (P. troglodytes). As a preliminary step to explore the dispersal strategies of female bonobos, this study aimed to determine the relations of sexual swelling development, behavioral and hormonal activation, and first ovulation relative to dispersal timing. We measured levels of urinary estrone conjugates (E 1 C) and pregnanediol glucuronide (PdG) from 14 nulliparous females in wild bonobo groups at Wamba in the Democratic Republic of the Congo, and recorded their copulations with mature males. When close to dispersal, female bonobos exhibited swelling of the sexual skin (labia minora and perianal region) that did not reach the mature stage. Urinary E 1 C levels and copulation rates increased slightly before dispersal and greatly increased after dispersal. Ovulatory or gestatory signs implied by daily hormone profiles were not detected until one to two years after dispersal. Our findings indicate that female bonobos disperse at an early pubertal stage before ovulatory cycling is established. This earlier dispersal than sexual maturation could allow female bonobos to postpone reproduction-related energy costs until they become familiar with their new group or gain more time finding the group more suitable for successful reproduction in the future before actually settling. Further demographic and genetic data from dispersal to reproduction will help clarify their dispersal strategies. • Development of female sexual swellings preceded dispersal. • Ovarian estrogen secretion began in the first year pre-dispersal. • Copulation with mature males started in the first year before females dispersed. • Ovulatory or gestatory signs were detected after the second year post-dispersal. [ABSTRACT FROM AUTHOR]

Dispersal is a major life history trait of social organisms influencing the behavioral and genetic structure of their groups. Unfortunately, primate dispersal is difficult to quantify, because of the rarity of these events and our inability to ascertain if individuals dispersed or died when they disappear. Socioecological models have been partially developed to understand the ecological causes of different dispersal systems and their social consequences. However, these models have yielded confusing results when applied to folivores. The folivorous red colobus monkey ( Procolobus rufomitratus) in Kibale National Park, Uganda is thought to exhibit female-biased dispersal, although both sexes have been observed to disperse and there remains considerable debate over the selective pressures favoring the transfers of males and females and the causes of variation in the proportion of each sex to leave the natal group. We circumvent this problem by using microsatellite DNA data to investigate the prediction that female dispersal will be more frequent in larger groups as compared to smaller ones. The rationale for this prediction is that red colobus exhibit increased within-group competition in bigger groups, which should favor higher female dispersal rates and ultimately lower female relatedness. Genetic data from two unequally sized neighboring groups of red colobus demonstrate increased female relatedness within the smaller group, suggesting females are less likely to disperse when there is less within-group competition. We suggest that the dispersal system is mediated to some degree by scramble competition and group size. Since red colobus group sizes have increased throughout Kibale by over 50% in the last decade, these changes may have major implications for the genetic structure and ultimately the population viability of this endangered primate. Am. J. Primatol. 75:478-490, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Inclusive fitness theory presumes a human ability to discriminate between kin and nonkin. The present study investigated to what extent computer-generated similarity or dissimilarity can be discerned as phenotypic resemblance or dissimilarity, respectively, on a conscious level. Furthermore, sex differences assumed from female dispersal theory were examined. Three warps, one of computed similarity and one of computed dissimilarity of varying degree to a reference face among them, were presented to subjects, who were asked to indicate the image that they perceived as the most similar or dissimilar, respectively, to the source face. Higher degrees of (dis-)similarity led to higher recognition rates, which, however, never exceeded 80 percent. Women achieved higher recognition rates than men and (dis-)similarity was recognized more easily in female faces by both male and female subjects. We hypothesize that these sex differences are due to an evolutionary adaptation enabling women to recognize potentially remote relatives when they have left their natal groups and joined others to avoid inbreeding. [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]

White-faced capuchins (Cebus capucinus) reside in multimale–multifemale groups characterized by female philopatry and frequent male dispersal. However, over the years we have observed five females immigrate into our study groups and 23 disappear/emigrate. We examined long-term demographic and behavioural data on three groups of C. capucinus residing in Santa Rosa, Costa Rica, between 1986 and 2007. During this time, 56 females resided in our study groups and as of June 2007, 23 were still present, ten were confirmed/presumed dead and 23 were missing. Here we review the circumstances surrounding the five immigrations and 23 missing females and evaluate three main hypotheses to explain female dispersal in a female philopatric species: inbreeding avoidance, reduction of intragroup feeding competition and infanticide avoidance. The two main predictions of the inbreeding avoidance hypothesis were not supported by our study; male tenure did not exceed female age at first birth and the majority of dispersers were parous females. The reduction in intragroup feeding competition hypothesis received moderate support; dispersing/disappearing females tend to leave during the dry season and they have fewer matrilineal kin than females remaining in their natal group. Our data were most consistent with the infanticide avoidance hypothesis in that females are more likely to disperse/disappear during years with male replacements, a time when infant deaths are also more common. These data provide further evidence of the large impact that the movement and actions of adult male white-faced capuchins have on the lives of females in this species. [ABSTRACT FROM AUTHOR]

Abstract: Different mating systems in group-living animals have characteristic behavioral correlates that are primarily related to mate competition. Mate competition may push individuals to selectively make dispersal decisions for the purpose of maximizing of opportunities for reproduction. The Sichuan snub-nosed monkey (Rhinopithecus roxellana) is a polygynous primate species endemic to China. We provide the first data on female dispersal in a free-ranging group of R. roxellana in the Zhouzhi National Nature Reserve, Qinling Mountains, China. Both adult and subadult female dispersal occurred. Immigration/emigration rates of adult females are higher than those of subadult females. Mate competition is one apparent driving force behind adult female dispersal, and inbreeding avoidance is the possible proximate factor influencing subadult female dispersal. Adult female R. roxellana employ various reproductive strategies related to dispersal, which may increase their reproductive success. [Copyright &y& Elsevier]

Flexibility (varying from monogamy in South Africa to polygyny in East Africa) has been documented in the mating system of the oribi ( Ourebia ourebi) by several authors. To investigate this, a population was studied in Northern KwaZulu-Natal (South Africa). The adult sex ratio was one male to 1.38 females and the mean group size was 2.1 (n = 13). Although monogamous and polygynous groups occurred in the study population, the polygynous groups were unstable and depended on seasonal food abundance. Comparison of oribi populations across Africa suggests that variation in the mating system is determined mainly by predation risk and altitude (most likely through its effect on graze quality). In areas of high predation risk, oribi can survive only when resource quality permits females to forage in groups, thereby allowing males to be polygynous. [ABSTRACT FROM AUTHOR]

Female social dispersal in primates differs from the general mammalian pattern of locational dispersal. Both nulliparous and parous females may disperse to another group. Several hypotheses can explain female social dispersal: reduction of predation risk, inbreeding avoidance, and offspring protection through mate choice. We tested these hypotheses with an extended data set of Thomas langurs (Presbytis thomasi) and investigated parameters of male behaviour that females may use in their dispersal decisions. Data were collected over a 12.5-year period from a wild population in Sumatra, Indonesia, allowing for some critical tests of the hypotheses. Females dispersed to a group smaller than their original one, thereby refuting the predation risk hypothesis. Maturing nulliparous females only dispersed when their father was resident. Therefore, dispersal by nulliparous females was best explained through inbreeding avoidance. Parous females transferred to young, adult males. These males provided better protection to offspring against predation and infanticide than the old, late tenure males. Therefore, females transfer to better protector males. The male behavioural cues that females use to assess male quality were unclear. Females, however, may use proxies of male age, such as group composition and acoustical characteristics of loud calls, as indicators of male quality. The results suggest that female mate choice is an important function of social dispersal by parous females. Its importance in locational dispersal remains to be investigated. [ABSTRACT FROM AUTHOR]

Female northern muriquis (Brachyteles arachnoides hypoxanthus or B. hypoxanthus) at the Estação Biológica de Caratinga/RPPN-FMA, Minas Gerais, Brazil typically disperse from their natal groups at an average age of 6.1 ± 0.6 years (median = 6.0 years, range = 5.3 - 7.8 years, n = 22), prior to the onset of puberty and sexual activity. Immigrants do not conceive until at least their second mating season, and the minimum interval from immigration to first reproduction has been 2.0 years. Age at first reproduction in dispersing females, previously estimated at 8.9 years, has now been documented at 9.0 and 9.25 years for two females whose birth dates are known. This is older than the 7.5 years at which the only female previously known to have reproduced in her natal group gave birth. Here, we present new data from a second female that reproduced in her natal group. This female (BA) was first observed to copulate at 5.5 years, and gave birth to her first infant at 7.25 years of age. Her 1.75-year cycling-to-first conception delay was only slightly shorter than the minimum recorded for immigrant females, and thus was not responsible for her young age at first reproduction compared to dispersing females. Although our sample size is small, our findings suggest that early puberty may permit females to reproduce in their natal group, implying a possible link between life history trade-offs and dispersal patterns. Because the only two females that have reproduced in their natal group were maternal sisters, it is also possible that maternal effects on age at puberty can impact dispersal patterns, particularly in small populations of primates. [ABSTRACT FROM AUTHOR]

It has been discussed in the literature that the presence of kin, particularly the presence of a women's own mother or her mother in law, may have fertility effects. We aimed to examine the effects of the presence of a woman's own or her husband's mother in the household on a woman's fertility in terms of number of children on a broad basis by analysing census data of over two million married women aged between 15 and 34 years from 14 countries worldwide. We find that with the exception of Iraq, across all countries, the majority of women live only with their spouse in the household. We further find that the presence of any mother in the household is invariably associated with a significantly lower number of children compared to women living only with their spouse. In addition, in most countries, a woman's number of children is lower if she lives with her own mother as compared to her husband's mother in the household. Number of children is nonlinearly associated with woman's age, the presence of any mother being related with an earlier start of childbearing but a shallower increase in number of children. We speculate that the presence of a mother in the household may slow down woman's reproduction, but also discuss alternative explanations., Competing Interests: We have no competing interests.