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Glycine receptors (GlyRs) are ligand-gated chloride channels comprising alpha (α1–4) and β subunits. The GlyR subunits play major roles in the mammalian central nervous system, ranging from regulating simple sensory information to modulating higher-order brain function. Unlike the other GlyR subunits, GlyR α4 receives relatively little attention because the human ortholog lacks a transmembrane domain and is thus considered a pseudogene. A recent genetic study reported that the GLRA4 pseudogene locus on the X chromosome is potentially involved in cognitive impairment, motor delay and craniofacial anomalies in humans. The physiologic roles of GlyR α4 in mammal behavior and its involvement in disease, however, are not known. Here we examined the temporal and spatial expression profile of GlyR α4 in the mouse brain and subjected Glra4 mutant mice to a comprehensive behavioral analysis to elucidate the role of GlyR α4 in behavior. The GlyR α4 subunit was mainly enriched in the hindbrain and midbrain, and had relatively lower expression in the thalamus, cerebellum, hypothalamus, and olfactory bulb. In addition, expression of the GlyR α4 subunit gradually increased during brain development. Glra4 mutant mice exhibited a decreased amplitude and delayed onset of the startle response compared with wild-type littermates, and increased social interaction in the home cage during the dark period. Glra4 mutants also had a low percentage of entries into open arms in the elevated plus-maze test. Although mice with GlyR α4 deficiency did not show motor and learning abnormalities reported to be associated in human genomics studies, they exhibited behavioral changes in startle response and social and anxiety-like behavior. Our data clarify the spatiotemporal expression pattern of the GlyR α4 subunit and suggest that glycinergic signaling modulates social, startle, and anxiety-like behaviors in mice. [ABSTRACT FROM AUTHOR]

With a strong tendency to socialise, the zebrafish is a useful model to study social behaviour, with implications for better treatments of social impairments, for instance in autism spectrum disorders. Although oxytocin is crucial for social behaviour in mammals, the importance of the fish orthologue – isotocin or zebrafish oxytocin (zOT) – for social behaviour in zebrafish is unclear. The aims of this study were firstly, to elucidate the receptor specificity of zOT and the related vasotocin or zebrafish vasopressin (zVP; the orthologue of mammalian vasopressin) and the nonpeptidergic oxytocin receptor antagonist L-368,899, and secondly to investigate if L-368,899 inhibits social preference in zebrafish. The potencies of ligands were evaluated for zOT/zVP family receptors in HEK293 cells. Adult and larval zebrafish were treated with L-368,899 or vehicle and subsequently assessed for social behaviour and anxiety (adults only). The antagonist L-368,899 specifically inhibited the two zOT receptors, but not the two zVP-1 receptors. The antagonist decreased social preference in adult and larval zebrafish. It did not affect anxiety in adults. These results indicate that endogenous zOT, and possibly zVP, is involved in social behaviour in zebrafish via either or both of the two zOT receptors, and show promise for future explorations of the anatomy and evolution of networks underlying social behaviour. [ABSTRACT FROM AUTHOR]

Various types of long-term stable relationships that individuals uphold, including cooperation and competition between group members, define social complexity in vertebrates. Numerous life history, physiological and cognitive traits have been shown to affect, or to be affected by, such social relationships. As such, differences in developmental modes, i.e. the 'altricial-precocial' spectrum, may play an important role in understanding the interspecific variation in occurrence of social interactions, but to what extent this is the case is unclear because the role of the developmental mode has not been studied directly in across-species studies of sociality. In other words, although there are studies on the effects of developmental mode on brain size, on the effects of brain size on cognition, and on the effects of cognition on social complexity, there are no studies directly investigating the link between developmental mode and social complexity. This is surprising because developmental differences play a significant role in the evolution of, for example, brain size, which is in turn considered an essential building block with respect to social complexity. Here, we compiled an overview of studies on various aspects of the complexity of social systems in altricial and precocial mammals and birds. Although systematic studies are scarce and do not allow for a quantitative comparison, we show that several forms of social relationships and cognitive abilities occur in species along the entire developmental spectrum. Based on the existing evidence it seems that differences in developmental modes play a minor role in whether or not individuals or species are able to meet the cognitive capabilities and requirements for maintaining complex social relationships. Given the scarcity of comparative studies and potential subtle differences, however, we suggest that future studies should consider developmental differences to determine whether our finding is general or whether some of the vast variation in social complexity across species can be explained by developmental mode. This would allow a more detailed assessment of the relative importance of developmental mode in the evolution of vertebrate social systems. [ABSTRACT FROM AUTHOR]

Allonursing, the nursing of nonfilial offspring, has been reported in a number of mammalian species; however, very few studies have investigated more than three hypotheses. The aim of our study was to investigate seven hypotheses explaining allonursing in captive giraffes. During 2007–2011, we observed 24 females and 37 calves in four zoological gardens in the Czech Republic, recording 2514 suckling events. We found that 83% of the females allonursed a nonfilial calf and 86.5% of calves allosuckled from a nonmaternal female; thus giraffes represent one of the highest occurrences of allonursing among nondomesticated mammals. The nonfilial calves more often allosuckled together with the filial ones than alone and tried to adopt positions where they may be harder to recognize, providing evidence for the milk theft hypothesis. In addition, the probability that a calf successfully allosuckled at least once from any female was higher when its mother allonursed successfully at least once than when she rejected calves. However, we found no evidence for the same rate of allonursing between reciprocal dyads of females and calves. Thus, we suggest that allonursing in giraffes is caused by offspring trying to steal milk and that females may tolerate this behaviour if reciprocal, in line with recent findings about giraffe sociality. [ABSTRACT FROM AUTHOR]

Social play is common in mammals but its adaptive significance is not well understood. A commonly held hypothesis is that social play allows juveniles to learn skills and rules for cooperation as adults. On this view, the adaptive benefit of social play derives from the benefits of cooperation as adults. However, cooperation is only beneficial if it is used in populations of predominantly cooperators; otherwise, it is a costly strategy. We investigated the latter problem by modeling the link between social play and subsequent adult cooperation using an agent-based model. In our model, agents had a play gene with allelic social play states (i.e., play or not play). Juveniles with a play gene learned to cooperate by successfully engaging in social play with another juvenile agent with a play gene. As adults, agents played the stag hunt game with other adults to obtain resources for reproduction. Those that learned to cooperate by playing as juveniles cooperated in the stag hunt game. When agents aggregated into small groups, we found that social play could evolve by facilitating the learning of cooperation. Our theoretical results also show that social play is a novel mechanism for the indirect evolution of cooperation. [ABSTRACT FROM AUTHOR]

Diverse photographic images (pictures) are used to promote wildlife tours on the Internet. But what pictures are used and are they likely to accurately reflect what visitors might see, and hence create realistic expectations for tourists? The relative importance of wildlife and the prevalence of iconic species were assessed for pictures on the Internet used by six English tour companies offering wildlife tours to very different destinations: Southern Africa and Australia. These were then compared with the likely visibility of wildlife at the destination. The content of 926 Southern African pictures representing 1316 different subjects, and 228 pictures representing 307 different subjects from Australia were classified into four themes (wildlife, landscapes/vegetation, activities, accommodation). Wildlife, particularly large mammals, was more frequently used for Southern African tours (43%) whereas pictures for Australian tours were often of landscapes (45%). Large, social mammals active during the day and hence highly visible (e.g. elephant, n= 64) were often used, while iconic, but cryptic, species such as koalas ( n= 7), Tasmanian devil ( n= 1), leopards ( n= 12), and black rhinos ( n= 2) were seldom used. Therefore, online pictures used for wildlife tours appear to merge well with what tourists are likely to see at the destination, but appear to diverge somewhat from established destination images for these two regions, particularly Australia. [ABSTRACT FROM AUTHOR]

Abstract: Although well documented in social insects, the possibility of behavioral differentiation during collective building has been poorly studied in mammals. In this context, the mound-building mouse Mus spicilegus is an interesting model. Under natural conditions, juveniles from different litters gather vegetal material and build a sophisticated structure, the mound, under which the mice will spend winter. The first steps of this complex building process may be elicited under laboratory conditions by offering cotton balls as building material. Spatio-temporal distribution of both animals and cotton balls was automatically recorded by RFID (Radio-Frequency Identification Device) technique. Our results revealed a behavioral differentiation during a collective building task. In a group of six individuals, only two mice (called carriers) transported 80% of the building material whereas the contribution of the remaining mice was weak or even non-existent. The proportion of carriers was constant in all of the six groups studied. This behavioral differentiation was implemented immediately after the building material was made available and remained stable during the 4 days of experiment. The high contribution level of carriers did not result from resource monopolization, nor did it depend on the gender or parental origin of the mice. [Copyright &y& Elsevier]

Spix’s disc-winged bats, Thyroptera tricolor, form small, long-term social groups in which members are loyal to a patch of forest but move on a daily basis between highly ephemeral roosting sites (partly unfurled Heliconia leaves). This species has been shown to exchange social calls that facilitate contact with nearby bats and recruitment to roost sites. During flight, T. tricolor emits ‘inquiry’ calls that frequently elicit a response from individuals that have already entered a furled leaf. These ‘response’ calls are then followed by the flying bat entering the occupied leaf roost. In this study, we examined variation in the structure of inquiry and response calls, and assessed whether calls encode information about individual or group identity that would allow for acoustic discrimination to occur. We found that both inquiry and response calls were sufficiently consistent within individuals, and divergent between individuals, to permit separation of individual bats based on call structure. We also found some evidence for group-specific signatures, although these were less defined than differences observed between individuals. While this does not confirm that Spix’s disc-winged bats can discriminate between individuals and groups based on call information, our results indicate that both call types have a broad enough parameter space for this to occur. [Copyright &y& Elsevier]

Abstract: Walrus are highly gregarious pinnipeds that can form herds of several hundreds or thousands of individuals when hauling out on ice or on land. They produce vocalisations in almost all social interactions, from aggressive vocalisations, contact calls involved in mother–calf bond to adult–adult communication to stereotyped courtship display during the mating season. The knowledge on walrus’ vocal behaviour and its perceptual abilities is limited due to the extreme difficulty of studying these animals in their natural environment. In the present study, we reported the results of a pilot experimental work on group/social vocal communication in captive Pacific Walruses (Odobenus rosmarus divergens). By analysing the main vocalisations produced by females and males during social interactions, we found some differences in their call characteristics compared to the Atlantic subspecies. In a second step, we experimentally demonstrated the abilities of females and mature males to discriminate between vocalizations of individuals from their own group and those of unknown individuals. In spite of the low sample size of animals, these findings on captive walruses improved knowledge of the cognitive abilities of this endemic Arctic species. [Copyright &y& Elsevier]

The vast majority of Mesozoic and early Cenozoic metatherian mammals (extinct relatives of modern marsupials) are known only from partial jaws or isolated teeth, which give insight into their probable diets and phylogenetic relationships but little else. The few skulls known are generally crushed, incomplete or both, and associated postcranial material is extremely rare. Here we report the discovery of an exceptionally large number of almost undistorted, nearly complete skulls and skeletons of a stem-metatherian, Pucadelphys andinus, in the early Palaeocene epoch of Tiupampa in Bolivia. These give an unprecedented glimpse into early metatherian morphology, evolutionary relationships and, especially, ecology. The remains of 35 individuals have been collected, with 22 of these represented by nearly complete skulls and associated postcrania. These individuals were probably buried in a single catastrophic event, and so almost certainly belong to the same population. The preservation of multiple adult, sub-adult and juvenile individuals in close proximity (<1 m2) is indicative of gregarious social behaviour or at least a high degree of social tolerance and frequent interaction. Such behaviour is unknown in living didelphids, which are highly solitary and have been regarded, perhaps wrongly, as the most generalized living marsupials. The Tiupampan P. andinus population also exhibits strong sexual dimorphism, which, in combination with gregariousness, suggests strong male-male competition and polygyny. Our study shows that social interactions occurred in metatherians as early as the basal Palaeocene and that solitary behaviour may not be plesiomorphic for Metatheria as a whole. [ABSTRACT FROM AUTHOR]

The evolution and expression of different forms of cooperative behaviour (e.g. feeding, guarding, sentinel duties, etc.) are usually studied independently, with few studies considering them as a single syndrome. However, studies investigating individuals' investment across a suite of different behaviours reveal that they are correlated, suggesting a single mechanism determining the evolution and expression of cooperative behaviours. A hormonal mechanism could achieve this, and one possibility is oxytocin (OT), which affects several prosocial or alloparental behaviours independently. We show, using a double-blind experiment, that peripheral administration of OT to social, free-living meerkats Suricata suricatta elevates a suite of cooperative behaviours. Treated individuals increase their contributions to communal, cooperative activities (digging, guarding, pup-feeding and associating with pups) and decrease initiation of aggressive interactions, compared with a saline control. This suggests that different forms of cooperative behaviour form a single syndrome with a common causal basis. If our peripherally administered OT acts in the same way as the naturally released hormone, then a general tendency to prosociality may be modulated by this hormonal system. Therefore, it may be difficult for an individual to decouple expression of cooperative behaviours that provide the practitioner with benefits from those that provide the recipient with benefits. It may also explain why social species typically exhibit a suite of cooperative behaviours, without having to invoke independent evolution of each. [ABSTRACT FROM AUTHOR]

The evolution of social monogamy in larger mammals is difficult to explain because males usually do not invest much in direct offspring care and might achieve greater fitness by deserting a pregnant female to reproduce with additional females elsewhere. It has been hypothesized that socially monogamous males remain with the female year-round to protect their offspring from infanticide by new immigrant males. We investigated this idea by analyzing all cases of infant loss in a wild population of white-handed gibbons ( Hylobates lar; Primates), in which most groups were socially monogamous and some polyandrous (137.5 group years). We examined the influence of (a) male intruder pressure on male immigration rates and (b) the presence of a new male in the group on infant loss. We found no relation between intruder pressure and male immigration rates. Infant loss was lowest (4.5%) for stable monogamy (probable father stayed from conception through infancy) and intermediate (25.0%; p = 0.166) for stable polyandry. If a new male immigrated after conception, however, the infant was lost in all cases ( p < 0.01) independent of the presumed father's presence. Overall, 83.3% of infant losses were associated with the presence of a presumably unrelated male. Although the sample size is small, our results provide the first true support for the idea that the risk of infanticide is an important factor in the evolution of social monogamy in larger mammals. [ABSTRACT FROM AUTHOR]

Scat DNA analyses and monthly monitoring were used to elucidate patterns of latrine use in a free-ranging population of a rare Australian marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus) Kerr. In all, 132 latrines were identified at large complex outcrops and on bedrock in drainage lines, creeks and rivers at a single woodland site in south-eastern mainland Australia. Annual cyclic variation in scat deposition was found over the two years that latrines were monitored. Peaks in scat deposition on latrines coincided with seasonal social behaviours and differed between sites on outcrops and sites along drainage lines. A marked increase in scat deposition on latrines in drainage lines was recorded during the mating season and at outcrop latrines when females were nursing young. Genetic analyses of scats collected over one breeding season revealed that multiple individuals of both sexes defaecated at latrines. The communal use of latrines during the mating season along with the seasonal patterns of scat deposition demonstrates that latrines are important scent-marking sites that facilitate social communication among individuals of this solitary-living species. The collective evidence indicates that latrines play a major role in aiding reproduction and interindividual spacing. [ABSTRACT FROM AUTHOR]

Animals spend a substantial proportion of their lives resting and consequently the choice of a sleeping site can dramatically affect an individual''s fitness. Sleeping sites have been implicated in predator defence and thermoregulation and their distribution can affect breeding and social systems in small mammals. Sleeping sites may constitute a limiting resource for females which experience energetic constraints to breeding and require shelter for their young. Despite the potential importance of sleeping sites, exhaustive studies of the factors determining their usage patterns are limited to a small number of mammal groups. We investigated how seasonal changes in temperature or the presence of young shape sleeping site usage patterns in a small primate, the grey mouse lemur, Microcebus murinus. Females preferred tree holes over nests and open sites and the usage duration of a particular tree hole site was affected by the physical characteristics likely to affect its insulation properties. Furthermore, climate variables strongly affected sleeping site choices and nests were chosen more often than tree holes during the wet season. However, when young were present preferences shifted back to tree holes. Preferred tree species used as sleeping sites as well as the properties of tree holes were rare among trees in the study area suggesting that sleeping sites may indeed be a limiting resource for female grey mouse lemurs. Our results suggest that in the study species sleeping site choices are governed by thermoregulatory considerations and their limited availability could also account for the social grouping. [Copyright &y& Elsevier]

Abstract: The neuropeptide Oxytocin (OT) has been implicated in many aspects of mammalian social behavior. This study investigates how OT interacts with two well-studied determinants of cooperative behavior: incentives and social information. Participants received OT or a placebo and played two economic games: a Coordination Game (with strong incentives to cooperate) and a Prisoner''s Dilemma (with weak cooperative incentives). OT enhanced cooperation only when social information was present, and this effect was significantly more pronounced in the Coordination Game. When social information was lacking, OT surprisingly decreased cooperation. Consistent with the well-established role of OT in trust-building and in social cognition, social information appears to be crucial for OT to boost cooperative expectations in an interdependent social interaction that provides incentives to cooperate. When these cues are absent, OT appears to instead elicit a risk-averse strategy. [Copyright &y& Elsevier]

Few studies on the welfare of captive bottlenose dolphins (Tursiops truncatus) have been carried out. Of these, most include information on animals kept in closed facilities or pools. The aim of this study was to assess the effect on the behavior of a group of dolphins by changing it from closed facilities, where it had been housed for nine years, to open facilities or sea pens. Ten bottlenose dolphins (Tursiops truncatus), one male and nine females, with an age range of 16 to 24 years were observed. Using a combination of scan and focal sampling a total of 96 hours were used to obtain information on the proportion of time on individual and social behaviors in both type of facilities. The results show that dolphins kept in closed facilities spent less time swimming and more time floating than in open facilities (P = 0.01). Likewise, the swimming pattern in closed facilities is in circles (P = 0.009) while in open facilities the linear pattern predominates (P = 0.02). Furthermore, while kept in closed facilities, dolphins spent more time interacting socially than in open facilities (P = 0.02). This information is useful to better understand the effect of different types of facilities on the behavior of captive dolphins. [ABSTRACT FROM AUTHOR]

Coalitions occur when multiple individuals cooperate against a common opponent or for a common goal. Coalition formation is a complex behavior, typically described in highly social and cognitively complex species. Surprisingly, we know little about the social and environmental factors that may select for the evolution of coalitions. We studied the evolution of coalitionary behavior by first redefining it in a continuous way that acknowledges variation in the degree to which animals collaboratively work toward a common goal. We then examined the evolutionary association of coalition complexity with 3 social factors (estrous duration, group size, and presence of a dominance hierarchy) and 3 environmental factors (habitat type, diurnality, and diet type). We found that estrous duration, group size, and dominance hierarchy were significantly correlated with coalition complexity and thus conclude that social factors are relatively more important in the evolution of complex coalitions than are environmental factors. From these results, we infer that complex coalitions may be the product of social factors that reduce female monopolizability and encourage the aggregation of multiple males. [ABSTRACT FROM AUTHOR]

Monogamy is a relatively rare social system in mammals, occurring only in about 3% of mammalian species. Monogamous species are characterized by the formation of pair-bonds, biparental care, and a very low level of sexual dimorphism. Whereas in most polygynous species males engage in more rough-and-tumble play than females, we predicted that males and females of monogamous species would have similar, or monomorphic, play behavior. In this study, we focused on two monogamous species: coppery titi monkeys ( Callicebus cupreus) and prairie voles ( Microtus ochrogaster). We documented the development of play behavior in both species, and quantified different types of play behavior. We did not find any sex differences in either species in the frequencies and types of play. However, we did find sex differences in the choice of play partner in titi monkeys: female offspring spent a higher proportion of time playing with their father, while male offspring played equally with their mother and father. It is possible that rough-and-tumble play behavior is monomorphic in many monogamous mammals, perhaps reflecting differences from polygynous species in the effects of exposure to early androgens or in the estrogen receptor distribution. However, more subtle differences in monomorphic play behavior, such as choice of partner, may still exist. [ABSTRACT FROM AUTHOR]

Bats are among the most diverse and most gregarious of all mammals. This makes them highly interesting for research on the causes and consequences of sociality in animals. Detailed studies on bat sociality are rare, however, when compared with the information available for other social mammals, such as primates, carnivores, ungulates, and rodents. Modern field technologies and new molecular methods are now providing opportunities to study aspects of bat biology that were previously inaccessible. Consequently, bat social systems are emerging as far more complex than had been imagined. Variable dispersal patterns, complex olfactory and acoustic communication, flexible context-related interactions, striking cooperative behaviors, and cryptic colony structures in the form of fission-fusion systems have been documented. Bat research can contribute to the understanding of animal sociality, and specifically to important topics in behavioral ecology and evolutionary biology, such as dispersal, fission-fusion behavior, group decisionmaking, and cooperation. [ABSTRACT FROM AUTHOR]

Traces the ancestral pattern of primate social organization. Overview of the social organization of different species of nocturnal prosimians and other mammals; Mammalian evolution and phylogenic relationships; Examination of the social organization of primates.

Reports on research updates about the origin of morality in mammals. Evolution of mammalian social behavior; Feelings possessed by primates; Primate cognitive capacities; Understanding of reciprocity.