Dominance Hierarchy Research Articles

The effect of sociality on competitive interactions among birds.

Sociality can provide many benefits, including increased foraging success, reproductive opportunities and defence against predation. How does sociality influence the dominance hierarchies of ecological competitors? Here, we address this question using a large citizen science dataset of competitive interactions among birds foraging at backyard feeders, representing a network of over 55 000 interactions among 68 common species. We first show that species differ in average group size (the number of conspecifics observed together) as a fundamental measure of sociality. When analysing heterospecific competition, we find that sociality is inversely related to dominance. On average, a single individual from a solitary species is more likely to displace a size-matched opponent than a single individual from a social species. Yet, we find that social species gain an increase in their competitive advantage when in the presence of their conspecifics, which may occur as a result of dynamics within their groups. Finally, we show that more social species have relatively fewer dominance interactions with heterospecifics, and more with conspecifics. Overall, these results demonstrate that sociality can influence competition in ecological networks. More social species have decreased competitive ability as individuals, but they may gain competitive ability in groups.

The Role of Environmental Enrichment and Back Fat Depth in the Intensity of Aggressive Behavior Performed by Sows during the Establishment of the Dominance Hierarchy.

For sows introduced into new groups, the aggressive behavior associated with establishing a social hierarchy represents a period of severe stress. The aim of this study was to investigate the effect of providing sows with an improved pen environment (straw in racks and ropes) on aggressive behavior after mixing and to understand the role played by sow back fat thickness and parity order. At 29 d post-service, sows were mixed into IMPROVED or CONTROL pens with individual feeding stalls (6 groups/treatment, 20 sows/group). Aggressive behavior was recorded for 2 h at mixing (T0) and 24 h (T1) and 3 weeks post-mixing (T21). Overall, the sows in the CONTROL pens performed more fighting behavior compared to the IMPROVED sows (p < 0.001). This difference was significant only at T21 (p < 0.001). Additionally, the sows in the CONTROL pens generally initiated more aggressive behaviors than the sows in the IMPROVED pens (p = 0.02). The sows with a low back fat thickness initiated more aggressive behaviors, but parity had no significant effect on any of the aggressive behaviors. These results indicate a beneficial effect of improvements to the pen environment on the aggression performed by group-housed sows between the time of mixing and three weeks later. The effect was reduced on the day of mixing, which is in accordance with the necessity for sows to employ aggression to establish the dominance hierarchy.

Co‐occurrence patterns in a steppe bird community: insights into the role of dominance and competition

Spatial co‐occurrence patterns are determined by environmental factors, such as food availability or habitat characteristics and by biotic associations. When resources are limited, competition which implies a dominant hierarchy can shape species assemblage. Here, we study space and time co‐occurrence of steppe passerines during the breeding season in a natural steppe habitat, its modulation by environmental filtering, potential biotic interactions and random processes. We applied the joint species distribution model of hierarchical modelling of species community (HMSC) to data on species presence–absence and environmental, temporal and spatial covariates acquired from seven plots in a natural steppe in central Spain during two consecutive years. Our results reveal the patterns of bird species co‐occurrence and suggest that this assemblage might be competitively structured. The assemblage appears to be configured around one dominant species, the Eurasian skylark, which establishes principally negative associations with many of the coexistent species. Our results contribute to the understanding of how competition and dominance processes, together with ecological constraints and other biotic associations, shape bird assemblages.

The interconnection of hierarchy, affiliative behaviours, and social play shapes social dynamics in Maremmana beef cattle

Dominance hierarchies can be interconnected with behaviours that are essential to manage social living, such as affiliative behaviours and social play, whose importance can already emerge in the early phases of life. Here, we carried out an observational study (all occurrences sampling) to investigate the possible interconnection between these three behavioural categories in a group of Maremmana beef cattle (n = 44, 6–21 months of age) in an extensive breeding system. We found that a clearly linear hierarchy is present in the group, and that the age of the animals positively correlated with their hierarchical ranks. Affiliative behaviours were directed up to the hierarchy: dominants received more affiliative behaviours and subordinates were generally starting the sessions, suggesting that affiliative behaviours may be used by subordinates to bond with dominants for possibly gaining some benefits. Social play mainly consisted of play fighting and dominant subjects played with the highest frequency. However, playful modality was independent from playmates’ relative rank position, with longer-lasting sessions being characterized by unbalanced and unreciprocated patterns. This indicates that play fighting in cattle has a competitive rather than cooperative nature and that it may be used as physical training to develop competitive skills in all groupmates. When play fighting was punctuated by affiliative behaviours, the playful sessions lasted longer. In this view, affiliative behaviours can have a communicative value useful in downgrading the competition emerging during play fighting. In conclusion, under naturalistic conditions young animals of beef cattle express all the behavioural repertoire typical of adulthood and their agonistic, affiliative, and playful behaviours are strongly interconnected in shaping social dynamics. Thus, our study suggests that extensive farming conditions are ideal to study the behavioural strategies domestic animals enact to form cohesive social groups. Such information is needed to enhance management and welfare of domestic ungulates.

Selective bilingualism: official language use and linguistic landscape in Hungarian-Romanian mixed schools in Romania

ABSTRACT In Romania most Hungarian-speaking children study in their mother tongue, in Hungarian-language classes. Some of these are organised in ‘mixed schools’, where parallel Hungarian and Romanian classes coexist in the same institution. Although these institutions seem a good solution for inter-ethnic coexistence, no systematic research has been conducted on their internal language policy and language practices yet. The aim of the paper is to examine the language policy of these institutions, by focusing on the language of two top-down elements of the linguistic landscape, school inscriptions and internal signs of rooms. The study argues that three language strategies can be distinguished: asymmetry, symmetry and quasi-asymmetry, which are influenced by the institutional characteristics of the school. Furthermore, the paper offers possibilities for applying its findings in different contexts and situations. By drawing attention to the limits of formal language policy, it argues that depending on the structural context they find themselves in, actors can openly contest or reinterpret even seemingly clear legal regulations, negotiating their applicability according to the dominant language hierarchies and ideologies they adhere to. Additionally, the paper provides insights concerning two methodological dilemmas in linguistic landscape research, namely, representativity and lack of explanatory depth of quantitative analysis.

From learning ‘who monkeys support’, we infer ‘What they know’

Though understanding what monkeys see and know without inferring anthropomorphically is virtually impossible, the more detail and concrete the ground of this inference we have, the more promising our surmise would be. A closer look into the male-male relation in cercopithecines, a genus of old world monkeys, confirms what scientists have theorized: in the absence of inclusive fitness advantage, the males cooperate closely with nonkins following the norm of reciprocity, resulting in a stratified rather than linear, continuous dominance hierarchy, as a function of seniority and age. This feature is ubiquitous and found in 3 species of macaques and yellow baboons; and it is reliably robust across 4 continents, 5 study sites, 17 troops, and 297 monkeys. In other words, although new members of a group are often at the prime age of belligerence, because senior males share a longer history of cohabitation and reciprocal relation with one another, they intervene in each other’s fight and outcompete the new members who are often not supported. This implies that, in cercopithecines, the support to nonkins may be guided by a mental scorebook, which enforces them to reciprocate in the future when their reciprocal partners are in need.

Social factors drive vocal exchanges in red-capped mangabeys (Cercocebus torquatus)

Of all the calls made by non-human primates, the function of short-distance contact calls has largely remained to be determined. These calls are the most frequent in the repertoire and are most often exchanged between individuals in a non-random way. To our knowledge, no study has ever examined how vocal exchanges are structured in red-capped mangabeys (Cercocebus torquatus), a semi-terrestrial monkey living in the African forest with a complex semi-tolerant/semi-despotic social system. Our goal was to assess the organization of contact call exchanges in this species and their relationship with individual and social factors such as age, affinity, and hierarchy. Therefore, we observed several captive groups of red-capped mangabeys and collected data on vocal behavior, as well as grooming, agonistic behavior, and spatial proximity. We defined a vocal exchange in this species as a series of contact calls made by two or more individuals within a maximum inter-caller interval of 2 s. At the individual level, the higher the individual's hierarchical rank, the less they initiated exchanges. Furthermore, the most socially integrated individuals had a longer average response time than the less integrated ones. At the dyadic level, preferred exchange partners were individuals often observed near one other or individuals most distant in age. Also, the further apart two individuals were in the dominance hierarchy, the shorter the response time. Our results support both the social bonding hypothesis and a modulating key role of the dominance hierarchy on the social use of contact calls, which is in line with the social style of this species.

Aviary measurements of dominance and affiliation between members of mixed-species birds flocks in southern China

In mutualistic interactions, all parties are usually considered to benefit; yet there may be asymmetries in mutualisms where some partners/individuals benefit more than others. Such is thought to be the case in mixed-species flocks of birds, where following species are thought to benefit more than leading species, and leading species may not be able to escape the association if they are subordinate to other species. We measured dominance and affiliation patterns of a mixed-species flock system of southern China in an aviary where these variables could be measured in a standardized way. In eight wild-caught flocks, the leading species, David's Fulvetta (Alcippe davidi), was usually among the more subordinate flock members (ranking 9 of 13 species, with the the most dominant species ranked number one, and dominance measured by normalized David's scores). Dominance was strongly influenced by body mass, and not by bill length or the number of individuals. Female fulvettas in particular tended to be among the most subordinate individuals in the flock. There was evidence of a negative relationship between a species pair's affiliation, measured as the percentage of all observations in which these two species were found perching together, and their difference in ranking in the dominance hierarchy, particularly when some ground species, which are not likely to remain in flocks long term, were removed from the analysis. Species pairs that had more pronounced differences in their dominance rankings were less likely to be affiliated, which is consistent with the idea that subordinate species may avoid dominants. David's Fulvetta is a strong information provider, so other species are likely benefitted in this relationship. Our data suggest one reason that fulvettas stay in flocks is that they may be subordinate and therefore have little control over who associates with them.

Migration, race, and gender: the policing of subversive solidarity actors in Morocco

The policing of racialised migrant people in Morocco and across the Maghreb has been violent since the 1990s. The intimidation of those who support migrant people and seek to denounce human rights abuses against them has become an important dimension of border control. This article investigates the policing of “subversive solidarity actors”: human rights defenders and activists who publicly or covertly engage in a critical stance on migration control policies and practices in Morocco. These forms of activism are considered a threat by the state because they make visible the brutality of migration governance and control in the country, which the state seeks to conceal. As objects of state mistrust and suspicion, solidarity actors experience everyday acts of intimidation and criminalisation. Drawing on ethnographic material and interviews with migrant people and subversive solidarity actors, this article demonstrates how these solidarity actors - much like migrant people themselves - are differentially targeted according to intersectional differences. Racist and gendered bordering logics characteristic of migration management seep into the differential policing of those who dare act or speak out in support of migrants’ rights. Race and gender provoke particular policing behaviours which are reinforced when people engage in politics or acts of solidarity considered subversive. This is reinforced by the persistence of racial hierarchies of domination in post-colonial Morocco, which still bear the legacy of the active enslavement of Black people in the country and the legacy of the country’s colonisation by Europeans. First, honing in on racial difference, the article sheds light on the differential policing of Black, Moroccan and white-European solidarity actors. While Black solidarity actors are often migrant people who have regularised their status and settled in Morocco, their decision to engage in subversive solidarity work marks them as “ungrateful guests” and relegates them to a position of vulnerability in which their administrative status is compromised. In contrast, white Europeans in Morocco tend to benefit from privileges and freedoms, including within the bureaucratic realm. Those engaging in subversive acts of solidarity may experience state intimidation or punitive acts of administrative exclusion from the country, however these usually (with some stark exceptions) amount to better treatment relative to the experiences of their Black and Moroccan counterparts. Finally, Moroccans engaging in subversive solidarity action are framed as “internal enemies” to the state and are hyper-aware that punitive action might be set in motion against them at any moment. Second, this article focuses on gender, which also plays an important role in determining the ways in which solidarity actors are policed and their scope of action. Gender inequalities remain deeply entrenched in Morocco and social norms profoundly gendered. Particularly for women, activism is considered deviant, giving rise to greater police and social scrutiny of their acts and attempts to govern their behaviour. While men tend to face professional threats as insidious punishment for their activism, attacks on women more often target their family or intimate life. This article emphasises the importance of taking the policing of solidarity actors into account to understand the policing of migration more broadly, stressing how the racist and gendered policing of migrant people bleeds into the disciplining of those who support them. We conclude with a discussion of how this policing impacts subversive solidarity actors and networks, by instilling fear and hindering (coordinated) action. While some interviewees demonstrated an awareness of both intersectional differences and overlapping experiences, we call for solidarity actors to mobilise these differences and experiences to strengthen their action on migration issues and their ability to withstand intimidation from state authorities.

Biometria testicular e hierarquia de dominância do queixada (Mammalia, Tayassuidae)

Abstract The objective of this study was to obtain data on the testicular biometry of the white-lipped peccary (Tayassu pecari) and to verify if there is a correlation between the individual’s biometric data with their dominance rank. Data were collected from 16 adult males, aged between two and seven years, who made up the same group. By the agonistic interactions analyses we calculated the linearity indexes (h') of the dominance hierarchy and dominance rank. At the end of the behavioral observations, males were captured to collect biometric data from the testis. White-lipped peccaries showed testicles located in a perineal position, inclined cranio-ventrally with oval shape, flattened laterally and with tenso-elastic consistency (2.54±0.07). There was variance in the means (± standard deviation) of testis length (5.88±1.05cm), width (4.24 ± 0.98cm), height (4.44±0.86cm), and total scrotal width (8.78±17.05). The linear dominance hierarchy described the social structure of the males of this group (h'&gt;0.9), with probability of linearity in the hierarchy greater than chance (P = 0.02). There was a correlation between dominance rank with the body mass, length and volume of the testicles. As in general the dimensions of the testicles are directly correlated with sperm production and also testosterone, this characteristic favors the reproductive performance of dominant white-lips males. Therefore, the characteristics of testicular biometry of white-lips should be considered for the selection of individuals more likely to reproduce in captivity favoring the conservation of this vulnerable species.

Неперевод как палимпсест в непрозрачной поэзии

Ezra Pound’s “Pisan Cantos” is a multi-layered palimpsest rewritten and written over previous editions several times, in which the non-translation of quotes, sayings and headlines becomes an aesthetically significant device. Younger branches of complex poetry after 1945, on the one hand, overcome Pound’s total project, on the other, inherit him through this ‘gap’. Within the framework of this article, the author explores how hermetic poetry (language writing, metarealism and generation of the 21st century) uses non-translation and untrans­latable to create/express political and ontological problems corresponding to this gap. So, in “Drafts” by Rachel Blau DuPlessis, palimpsest exposes the very deployment of language, writing, the ‘trace’ of other languages — all this develops together with the optics of studying writing and the loosening of the dominant hierarchies of poetic subjectivity and artistic form. In the poetry of metarealists Arkady Dragomoshchenko and Alexei Parshchikov, non-translation serves as a way of creating palimpsest marginalia, structuring the perception of interweaving images both through donor text and through the transformation of its motives. And the discommunicative palimpsest of Ekaterina Zakharkiv’s poem “Hiroo Onoda” is based on the unrepresentative function of the non-translation, when the collision of different lan­guages, quotes and references creates both difficulty in perception and communicative faults in the narrative fabric of the work. Thus, the article is an attempt to derive points on a con­tour map of poetic practices, showing both the formation of a way of inter-linguistic inte­rac­tion within the text that is different from multilingualism, and the ways of inheritance through the rupture of the complex and ambiguous nature of Ezra Pound’s “Cantos”, which gave rise not only to a new type of modernist epic, but also a special type of poetic palimpsest.

Motherhood dalam Novel Chanson Douce Karya Leila Slimani: Analisis Dekonstruksi Derrida

Motherhood ideology is commonly found in literary works, including narratives depicting the figure of a mother. In literature, especially in Europe, the figure of a mother is mystified and is often associated with the figure of the Virgin Mary. This is closely related to the oppression experienced by women due to the inequality of gender construction produced by society. The novel Chanson Douce by Leila Slimani narrates two mothers with different backgrounds. This study aims to carry out a deconstruction reading, especially on the discourse of motherhood. In interpreting something we are always dominated by dominant hierarchies and superior poles which are considered as "single truth". This single truth can lead to vulnerability to discrimination or service. The deconstruction method used in this study uses the concepts of trace and difference, in readings that lead to the meaning of texts that are "friendly" to the others. The results of this study lead us to new questions regarding the challenges of motherhood in this post-industrial era.

Motherhood dalam Novel Chanson Douce Karya Leila Slimani: Analisis Dekonstruksi Derrida

Motherhood ideology is commonly found in literary works, including narratives depicting the figure of a mother. In literature, especially in Europe, the figure of a mother is mystified and is often associated with the figure of the Virgin Mary. This is closely related to the oppression experienced by women due to the inequality of gender construction produced by society. The novel Chanson Douce by Leila Slimani narrates two mothers with different backgrounds. This study aims to carry out a deconstruction reading, especially on the discourse of motherhood. In interpreting something we are always dominated by dominant hierarchies and superior poles which are considered as "single truth". This single truth can lead to vulnerability to discrimination or service. The deconstruction method used in this study uses the concepts of trace and difference, in readings that lead to the meaning of texts that are "friendly" to the others. The results of this study lead us to new questions regarding the challenges of motherhood in this post-industrial era.

The language of healthcare worker emotional exhaustion: A linguistic analysis of longitudinal survey.

Emotional exhaustion (EE) rates in healthcare workers (HCWs) have reached alarming levels and been linked to worse quality of care. Prior research has shown linguistic characteristics of writing samples can predict mental health disorders. Understanding whether linguistic characteristics are associated with EE could help identify and predict EE. To examine whether linguistic characteristics of HCW writing associate with prior, current, and future EE. A large hospital system in the Mid-West had 11,336 HCWs complete annual quality improvement surveys in 2019, and 10,564 HCWs in 2020. Surveys included a measure of EE, an open-ended comment box, and an anonymous identifier enabling HCW responses to be linked across years. Linguistic Inquiry and Word Count (LIWC) software assessed the frequency of one exploratory and eight a priori hypothesized linguistic categories in written comments. Analysis of covariance (ANCOVA) assessed associations between these categories and past, present, and future HCW EE adjusting for the word count of comments. Comments with <20 words were excluded. The frequency of the linguistic categories (word count, first person singular, first person plural, present focus, past focus, positive emotion, negative emotion, social, power) in HCW comments were examined across EE quartiles. For the 2019 and 2020 surveys, respondents wrote 3,529 and 3,246 comments, respectively, of which 2,101 and 1,418 comments (103,474 and 85,335 words) contained ≥20 words. Comments using more negative emotion (p < 0.001), power (i.e., references relevant to status, dominance, and social hierarchies, e.g., own, order, and allow) words (p < 0.0001), and words overall (p < 0.001) were associated with higher current and future EE. Using positive emotion words (p < 0.001) was associated with lower EE in 2019 (but not 2020). Contrary to hypotheses, using more first person singular (p < 0.001) predicted lower current and future EE. Past and present focus, first person plural, and social words did not predict EE. Current EE did not predict future language use. Five linguistic categories predicted current and subsequent HCW EE. Notably, EE did not predict future language. These linguistic markers suggest a language of EE, offering insights into EE's etiology, consequences, measurement, and intervention. Future use of these findings could include the ability to identify and support individuals and units at high risk of EE based on their linguistic characteristics.

Parasitized Collared Aracari (Pteroglossus torquatus) killed by conspecific

We report an incident of intraspecific aggression behavior in Collared Aracari (Pteroglossus torquatus) in the municipality of San Rafael, Antioquia. The record was made on Saturday 21 may 2022 in the afternoon, with the help of binoculars and a photographic camera. This is the first report of this behavior in which the attacked individual was found to be visibly parasitized by larvae of dipterans (myiasis). The aggression observed could have occurred in the context of intraspecific within-group dominance hierarchy, for competition of resources including mates, food and nesting cavities. However, it is also possible that it could have an importance in preventing or reducing parasite infection in the group. This observation opens the door to further questions related to the prevalence of dipteran parasitism in Pteroglossus torquatus and to its relevance to group behavior and parasitism avoidance.

A tale of two hierarchies: Hormonal and behavioral factors underlying sex differences in social dominance in cooperative breeding callitrichids

Callitrichid primates are recognized for high levels of sociality in small groups, their great behavioral flexibility, and single-female dominant hierarchies. Previous work has highlighted that dominant, breeding callitrichids engage in behavioral and hormonal reproductive suppression of related and unrelated subordinates by both producing more offspring, having higher levels of ovulatory hormones, and accessing more sociosexual opportunities. This suppression constitutes a nexus of changes in pituitary responsiveness, ovarian cyclicity, sexual behavior, affiliation, and aggression. In this review, I will highlight important features that characterize callitrichid social hierarchies across broad social contexts. Dominant females sometimes exert reproductive suppression on subordinate nonbreeding females, but this suppression varies across callitrichids based on social stability and changes in group composition, particularly related to the number, experience, and age of nonbreeding subordinates. Meanwhile, dominant males may induce suppression of reproduction in subordinate males, but these effects occur by different behavioral and endocrine mechanisms and to a much lesser extent than their female counterparts; While dominant female callitrichids usually show higher levels of aggression relative to their male counterparts, callitrichids show a general absence of intersexual dominance, likely as an effort of maintaining a cohesive breeding pair within a stable social group and social cooperation. Future efforts are needed to identify precise neuroendocrine mechanisms underlying the presence of sex differences in callitrichid behavior separate from peripheral reproductive function. This is especially important with regard to parental experience, social relationships, development and aging, with larger implications toward understanding sex differences in overall health and wellbeing.

Breeding displacement in gray wolves (Canis lupus): Three males usurp breeding position and pup rearing from a neighboring pack in Yellowstone National Park.

Gray Wolves (Canis lupus) are territorial, group living carnivores that live in packs typically consisting of a dominant breeding pair and their offspring. Breeding tenures are relatively short and competitive, with vacancies usually occurring following a breeder's death, and are often filled by unrelated immigrants or by relatives of the previous breeder. The frequency and conditions of active breeder displacements are poorly understood. Position changes in the dominance hierarchy are common yet rarely documented in detail. We describe a male breeding position turnover in a wolf pack by males from a neighboring pack in mid-summer 2016 in Yellowstone National Park. Over the course of two months, three males from the Mollie's pack displaced the breeding male of the neighboring Wapiti Lake pack, joined the pack's two adult females, and subsequently raised the previous male's four approximately three-month old pups. In the five years following the displacement (2017 to 2021), at least one of the intruding males has successfully bred with the dominant female and most years with a subordinate female (who was one of the pups at the time of displacement). The pack reared pups to adulthood each year. Male breeding displacements are likely influenced by male-male competition and female mate choice. These changes are the result of individuals competing to improve breeding position and may lead to increased pack stability and greater reproductive success. We report in detail on the behavior of a closely observed breeding displacement and we discuss the adaptive benefits of the change.

Adult sex ratios and partial dominance of females over males in the rock hyrax

Competition in group-living animals often results in a dominance hierarchy. The sex that is larger (usually the males) generally dominates the one that is smaller (the females). In certain species, however, despite being smaller, the females dominate several males. Female dominance over males may here arise from the self-reinforcing effects of winning and losing fights, the so-called winner-loser effect, as demonstrated in the model DomWorld. In the model, females may become dominant over more males when the percentage of males in the group is higher due to the higher intensity of aggression of males than females combined with the higher frequency of male–male fights. This association between female dominance and the percentage of adult males in the group has been confirmed in several primate species. Since in the model DomWorld this association requires few assumptions, it should be tested beyond primates. In the present study, we investigated it in the group-living rock hyrax (Procavia capensis), because it fulfilled most requirements. We used data on adults from six groups, collected over 20 years in natural colonies in Israel. We confirmed that body weight and intensity of aggression was greater in males than females. Three measurements indicated that females dominated ca. 70% of the males. Unexpectedly, only in the data where groups comprised several males, female dominance over males was shown to increase with male percentage, but not when including (the many) years in which groups comprised a single male. We attribute this non significance to the limited male–male interactions. One of the requirements of DomWorld is that individuals live in permanent groups, but in rock hyrax there were also bachelor males, that were not permanently associated with a group. Thus, we expected and confirmed that there was no association between the percentage of males and female dominance over males when including them. In conclusion, our results support the hypothesis that the winner-loser effect contributes to the dominance of females over males, and the association between the percentage of males in a group and female dominance over males requires an extra criterion: that most groups contain multiple males.

Predictors of dominance rank and agonistic interactions in captive Livingstone's fruit bats.

Male dominance hierarchies have been studied in many animals but rarely in bats (Chiroptera). The dominance rank of social animals may dictate access to resources and mates; therefore, it has important implications for an individual's fitness and is crucial for successful captive management. Between January and December 2018, at both Bristol Zoo Gardens (Bristol, UK) and Jersey Zoo (Jersey, British Isles), we observed 19 male Livingstone's fruit bats Pteropus livingstonii using focal follows for 345 h overall, noting the outcome of all agonistic interactions. We recorded instigators of interactions, along with winners and losers, and analyzed these data using the R-package "EloRating" to create Elo-rating temporal plots of dominance ranks. We used generalized linear mixed models and multiple linear regression to analyze interaction data and test hypotheses regarding predictors of dominance rank, frequency of agonistic interaction, and choice of interaction partner. Age was positively correlated with dominance rank up to around year 9, when an asymptote was attained. Highly ranked bats instigated the most agonistic interactions, and largely directed these interactions at bats with much lower rankings than themselves. Hierarchies were extremely stable throughout the data collection period at both sites. We conclude that Livingstone's fruit bats have a stable linear dominance hierarchy, with high-ranking, typically older males instigating the most interactions with lowest ranking males to secure dominance rank. This study adds to the limited discourse on Pteropus social behaviors, indicating that some bat species may have social systems similar in complexity to some nonhuman primates.

Ecology of large felids and their prey in small reserves of the Yucatán Peninsula of Mexico.

Jaguars and pumas are top-predator species in the Neotropics that are threatened by habitat destruction, illegal poaching of their body parts and their favored prey, and by the human-wildlife conflicts that arise when predators attack livestock. Much of the remaining felid habitat in the Americas is in protected nature reserves that are too small and isolated to support local populations. Surrounding forests therefore play a vital role in felid conservation. Successful long-term conservation of these two felids requires evidence-based knowledge of their biological and ecological requirements. We studied population distributions of jaguars and pumas and their prey in and between two small, private reserves of the Northern Yucatán Peninsula, Mexico, with areas of 25 and 43 km2. During 2 years of camera trapping (2015 and 2016), we detected 21 jaguars, from which we estimated an average space requirement of 28-45 km2/individual. Dietary niche overlap exceeded random expectation. The most frequently occurring prey items in jaguar and puma diets were collared peccary and deer. Jaguar also favored nine-banded armadillos and white-nosed coati, while puma favored canids. Both felids avoided ocellated turkey. Overall, diet of jaguars was less species-rich, but similar in niche breadth, to that of pumas. A fluid use of space by both species, in 2015 tending toward mutual attraction and in 2016 toward partial exclusion of pumas by jaguars, combined with the high dietary overlap, is consistent with a dominance hierarchy facilitating coexistence. Jaguars and pumas favor the same prey as the people in local communities who hunt, which likely will intensify human-wildlife impacts when prey become scarce. We conclude that even small reserves play an important role in increasing the continuity of habitat for prey and large felids, whose generalist habits suppress interspecific competition for increasingly limiting prey that are largely shared between them and humans.