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Silk, J. B. (2007). Social Components of Fitness in Primate Groups. Science, 317(5843), 1347–1351.
Abstract: There is much interest in the evolutionary forces that favored the evolution of large brains in the primate order. The social brain hypothesis posits that selection has favored larger brains and more complex cognitive capacities as a means to cope with the challenges of social life. The hypothesis is supported by evidence that shows that group size is linked to various measures of brain size. But it has not been clear how cognitive complexity confers fitness advantages on individuals. Research in the field and laboratory shows that sophisticated social cognition underlies social behavior in primate groups. Moreover, a growing body of evidence suggests that the quality of social relationships has measurable fitness consequences for individuals.
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Sigurjónsdóttir, H. (2007). Equine learning behaviour: The importance of evolutionary and ecological approach in research. Behav. Process., 76, 40–42.
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Shrader, A. M., Kerley, G. I. H., Kotler, B. P., & Brown, J. S. (2007). Social information, social feding, and competition in group-living goats (Capra hircus). Behav. Ecol., 18(1), 103–107.
Abstract: There are both benefits (e.g., social information) and costs (e.g., intraspecific competition) for individuals foraging in groups. To ascertain how group-foraging goats (Capra hircus) deal with these trade-offs, we asked 1) do goats use social information to make foraging decisions and 2) how do they adjust their intake rate in light of having attracted by other group members? To establish whether goats use social information, we recorded their initial choice of different quality food patches when they were ignorant of patch quality and when they could observe others foraging. After determining that goats use social information, we recorded intake rates while they fed alone and in the presence of potential competitors. Intake rate increased as the number of competitors increased. Interestingly, lone goats achieved an intake rate that was higher than when one competitor was present but similar to when two or more competitors were present. Faster intake rates may allow herbivores to ingest a larger portion of the available food before competing group members arrive at the patch. This however, does not explain the high intake rates achieved when the goats were alone. We provide 2 potential explanations: 1) faster intake rates are a response to greater risk incurred by lone individuals, the loss of social information, and the fear of being left behind by the group and 2) when foraging alone, intake rate is no longer a trade-off between reducing competition and acquiring social information. Thus, individuals are able to feed close to their maximum rate.
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Shier, D. M., & Owings, D. H. (2007). Effects of social learning on predator training and postrelease survival in juvenile black-tailed prairie dogs, Cynomys ludovicianus. Anim. Behav., 73(4), 567–577.
Abstract: We examined how social context and experience affected development of antipredator behaviour and subsequent postrelease survival in the black-tailed prairie dog. Captive-reared juveniles were initially exposed to four stimulus animals: a ferret, a rattlesnake, a hawk and a cottontail control (pretraining tests). Subjects were then trained with or without an adult female demonstrator. Training involved exposure to each stimulus animal two to three times over 5 weeks. After training, each juvenile was retested with each stimulus animal (post-training tests). During pretraining tests, juveniles responded differentially to the stimulus animals. They were least active with the snake, fled the most in tests with the hawk, and were less vigilant with the ferret than with the snake. Following training, juveniles trained with experienced adults were more wary with all three predators than juveniles trained without an experienced adult present. We then compared the antipredator behaviour of captive-reared juveniles trained with experienced adult females with that of wild-reared juveniles of the same age. For all behavioural measures except shelter use, wild-experienced animals differentiated more strongly among predator types than did captive-trained juveniles. One year after reintroduction, survivorship of juveniles trained with experienced adults was higher than that of juveniles trained without experienced adults, but did not differ from that of wild-reared juveniles. These findings provide the first evidence that social transmission of antipredator behaviour during training can enhance long-term survival following release and that as long as a social training regime is used, predator avoidance training can emulate experience acquired in the wild.
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Shettleworth, S. J. (2007). Animal behaviour: planning for breakfast. Nature, 445(7130), 825–826.
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Shepherd, S. V., & Platt, M. L. (2007). Spontaneous social orienting and gaze following in ringtailed lemurs (Lemur catta). Anim. Cogn., .
Abstract: Both human and nonhuman primates preferentially orient toward other individuals and follow gaze in controlled environments. Precisely where any animal looks during natural behavior, however, remains unknown. We used a novel telemetric gaze-tracking system to record orienting behavior of ringtailed lemurs (Lemur catta) interacting with a naturalistic environment. We here provide the first evidence that ringtailed lemurs, group-living prosimian primates, preferentially gaze towards other individuals and, moreover, follow other lemurs' gaze while freely moving and interacting in naturalistic social and ecological environments. Our results support the hypothesis that stem primates were capable of orienting toward and following the attention of other individuals. Such abilities may have enabled the evolution of more complex social behavior and cognition, including theory of mind and language, which require spontaneous attention sharing. This is the first study to use telemetric eye-tracking to quantitatively monitor gaze in any nonhuman animal during locomotion, feeding, and social interaction. Moreover, this is the first demonstration of gaze following by a prosimian primate and the first to report gaze following during spontaneous interaction in naturalistic social environments.
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Sharon, L., & Crowell-Davis, S. L. (2007). Sexual behavior of mares. Horm Behav, 52(1), 12–17.
Abstract: The mare is seasonally polyestrus, having an anovulatory period during the short light days of late fall and early winter, and beginning to ovulate as the days become longer during the winter. The complete estrus cycle is typically about 3 weeks, with 5 to 7 days of estrus and approximately 2 weeks of diestrus. When a mare lives within the natural social structure of the horse, i.e. a family band with several adult mares and one or more stallions, estrus is characterized by repeatedly approaching the stallion, frequent urination, deviating the tail away from the perineum, and standing still with the hind limbs spread apart. Diestrus is characterized by avoidance of an approaching stallion, and aggression toward the stallion, such as squealing, striking, and kicking, if he persists in attempting to court the diestrus mare. However, mares and stallions with long-term social relationships will often rest together, graze together and groom each other, all without sexual interactions. Hormonally, estrous behavior in the mare is initiated by estradiol that is secreted by the follicle, while estrous behavior is suppressed by progesterone, secreted by the corpus luteum. Mares are unusual among the ungulates in that they periodically exhibit estrous behavior during the anovulatory period. This is probably due to the release of estrogenic steroids secreted by the adrenal cortex. The display of sexual behavior by the mare throughout the year is thought to facilitate maintenance of the horse's social structure, in which the male remains with a group of females year round, in contrast with most ungulates in which the females and males only come together during the mating season.
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Seed, A. M., Clayton, N. S., & Emery, N. J. (2007). Postconflict third-party affiliation in rooks, Corvus frugilegus. Curr Biol, 17(2), 152–158.
Abstract: Conflict features in the lives of many animal species and induces social stress mediated by glucocorticoid hormones [1]. Postconflict affiliation, between former opponents (reconciliation) or between former opponents and a bystander (third-party affiliation), has been suggested as a behavioral mechanism for reducing such stress [2], but has been studied almost exclusively in primates [3]. As with many primates, several bird species live in social groups and form affiliative relationships [4]. Do these distantly related animals also use affiliative behavior to offset the costs of conflict? We studied postconflict affiliation in a captive group of rooks. Unlike polygamous primates, monogamous rooks did not reconcile with former opponents. However, we found clear evidence of third-party affiliation after conflicts. Both initiators and targets of aggression engaged in third-party affiliation with a social partner and employed a specific behavior, bill twining, during the postconflict period. Both former aggressors and uninvolved third parties initiated affiliative contacts. Despite the long history of evolutionary divergence, the pattern of third-party affiliation in rooks is strikingly similar to that observed in tolerant primate species. Furthermore, the absence of reconciliation in rooks makes sense in light of the species differences in social systems.
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Scordato, E. S., & Drea, C. M. (2007). Scents and sensibility: information content of olfactory signals in the ringtailed lemur, Lemur catta. Anim. Behav., 73(2), 301–314.
Abstract: The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has well-developed scent glands and shows a suite of scent-marking behaviour. To assess the information content of different types of scent gland secretions, we decoupled olfactory cues from the visual and behavioural modalities with which scent marking is normally associated. We presented male and female subjects (signal receivers) with a series of choice tests between odours derived from conspecific donors (signal senders) varying by sex, age, social status and reproductive condition. We additionally examined the influence of the receivers' reproductive state and familiarity with the signaller. The reproductive condition, social status and familiarity of senders and receivers affected signal transmission; specifically, male receivers attended most to the odours of conspecifics in breeding condition and to the odours of familiar, dominant animals. By contrast, females varied their responses according to both their own reproductive state and that of the sender. Based on male and female patterns of countermarking, we suggest that scent marking serves a function in intergroup spacing and intrasexual competition for both sexes, as might be expected in a female-dominant species. By contrast, minimal female interest in male odours counters a female mate choice function for scent marking in this species. Nevertheless, scent marks are critical to male-male competition and, therefore, may be subject to sexual selection.
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Schultz, P. N., Remick-Barlow, G. A., & Robbins, L. (2007). Equine-assisted psychotherapy: a mental health promotion/intervention modality for children who have experienced intra-family violence. Health & Social Care in the Community, 15(3), 265–271.
Abstract: Equine-assisted psychotherapy (EAP) is a specialized form of psychotherapy using the horse as a therapeutic tool. This modality is designed to address self-esteem and personal confidence, communication and interpersonal effectiveness, trust, boundaries and limit-setting, and group cohesion. Substantial numbers of children witness family violence. There is evidence that violence between parents has adverse effects on the children in the family. These children are at greater risk of behavioural problems and mental health disorders, including anxiety, anger, depression and suicidal ideations, withdrawal, low self-esteem, and attention deficit hyperactivity disorder. The purpose of the present pilot study was to test the efficacy of EAP in a cross-sectional group of children referred to a psychotherapist for various childhood behavioural and mental health issues over an 18-month period (June 2003–January 2005). Sixty-three children received a mean number of 19 EAP sessions. Scores on the Children's Global Assessment of Functioning (GAF) Scale were determined pre- and post-treatment. The mean (± standard deviation, SD) pretreatment score was 54.1 (SD 3.2) and post treatment mean score was 61.7 ± 5.0 (t = 9.06, d.f. = 96, P < 0.001). All children showed improvement in GAF scores, and there was a statistically significant correlation between the percentage improvement in the GAF scores and the number of sessions given (r = 0.73, P = 0.001). Univariate analysis showed that the greatest improvement in the GAF scores occurred in the youngest of the subjects. Children in the group who had a history of physical abuse and neglect had a statistically significant greater percentage improvement in GAF scores after treatment than those who did not have a history of abuse and neglect. This study has demonstrated a quick response to EAP, especially in younger children, but it remains to be determined what kind of long-term effects this type of intervention may provide.
Keywords: children; equine; intra-family violence; mental health; psychotherapy
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