|
|
Jørgensen, G. H. M., Liestøl, S. H. - O., & Bøe, K. E. (2011). Effects of enrichment items on activity and social interactions in domestic horses (Equus caballus). Appl. Anim. Behav. Sci., 129(2-4), 100–110.
Abstract: The aim of this study was to investigate the use of items intended to provide enrichment during turnout, both for individual and group kept horses in an attempt to reduce the amount of passive behaviours. The study was divided into two parts, where study 1 involved eight horses rotated through eight individual paddocks, each containing one of seven enrichment items and one paddock being kept without item, functioning as a control. The horses' item-directed behaviours; passive behaviours or other non-item related activities were scored using instantaneous sampling, every minute for 1 h at the beginning and the end of the turnout period. Study 2 involved six horse groups (3-6 horses) and the same scoring methods and ethogram as in study 1. The four items that the horses interacted the most with during study 1 (straw STRA, ball filled with concentrates CBALL, branches BRAN and scratching pole POLE) are investigated in study 2. In addition, the amount of social interactions was recorded. Both horses kept individually (P < 0.05) and in groups (P < 0.0001) performed significantly more item-directed behaviours towards edible items like STRA and CBALL than other objects. There was, however, no overall relation between the numbers of item-directed behaviours and the number of passive behaviours observed, indicating that the enrichment items did not alone reduce the amount of passive behaviours during turnout periods. Such a reduction was, however, only apparent when horses spent more time eating green leaves growing on the paddock surface (R = -0.97 study 1, R = -0.67 study 2, P < 0.0001). Access to STRA in group kept horses also seemed to reduce the amount of agonistic behaviours (P < 0.0001). In conclusion, if grass is not available in paddocks, the provision of roughage reduces the amount of passive behaviours in singly kept horses and it also reduces the risk of agonistic interactions between horses kept in group.
|
|
|
|
Byrne, R. W., Whiten, A., & Henzi, S. P. (1990). Social relationships of mountain baboons: Leadership and affiliation in a non-female-bonded monkey. Am. J. Primatol., 20(4), 313–329.
Abstract: Abstract 10.1002/ajp.1350200409.abs Instead of close and differentiated relationships among adult females, the accepted norm for savanna baboons, groups of Drakensberg mountain baboons (Papio ursinus) showed strong affiliation of females towards a single male. The same male was usually the decision-making animal in controlling group movements. Lactating or pregnant females focused their grooming on this “leader” male, producing a radially patterned sociogram, as in the desert baboon (P. hamadryas); the leader male supported young animals in the group against aggression and protected them against external threats. Unlike typical savanna baboons, these mountain baboons rarely displayed approach-retreat or triadic interactions, and entirely lacked coalitions among adult females. Both groups studied were reproductively one-male; male-female relationships in one were like those in a unit of a hamadryas male at his peak, while the other group resembled the unit of an old hamadryas male, who still leads the group, with a male follower starting to build up a new unit and already monopolizing mating. In their mountain environment, where the low population density suggests conditions as harsh for baboons as in deserts, adults in these groups kept unusually large distances apart during ranging; kin tended to range apart, and spacing of adults was greatest at the end of the dry, winter season. These facts support the hypothesis that sparse food is responsible for convergence with hamadryas social organization. It is suggested that all baboons, though matrilocal, are better categorized as “cross-sex-bonded” than “female bonded”.
|
|
|
|
Schwab, C., Bugnyar, T., Schloegl, C., & Kotrschal, K. (2008). Enhanced social learning between siblings in common ravens, Corvus corax. Anim. Behav., 75(2), 501–508.
Abstract: It has been suggested that social dynamics affect social learning but empirical support for this idea is scarce. Here we show that affiliate relationships among kin indeed enhance the performance of common ravens, Corvus corax, in a social learning task. Via daily behavioural protocols we first monitored social dynamics in our group of captive young ravens. Siblings spent significantly more time in close proximity to each other than did nonsiblings. We subsequently tested birds on a stimulus enhancement task in model-observer dyads composed of both siblings and nonsiblings. During demonstration the observer could watch the model manipulating one particular object (target object) in an adjacent room. After removing the model, the observer was confronted with five different objects including the former target object. Observers from sibling dyads handled the target object for significantly longer periods of time as compared with the other four available objects, whereas observers from nonsibling dyads did not show a preference for the target object. Also, siblings matched the model's decision to cache or not to cache objects significantly more often than did nonsiblings. Hence, siblings were likely to attend to both, the behaviour of the model (caching or noncaching) and object-specific details. Our results support the hypothesis that affiliate relations between individuals affect the transmission of information and may lead to directed social learning even when spatial proximity has been experimentally controlled for.
|
|
|
|
Romano, N., Vitale, F., Alesi, D. R., Bonura, F., La Licata, R., Intonazzo, V., et al. (1992). The changing pattern of human immunodeficiency virus type 1 infection in intravenous drug users. Results of a six-year seroprevalence study in Palermo, Italy. Am J Epidemiol, 135(11), 1189–1196.
Abstract: A cross-sectional seroepidemiologic study was carried out between 1985 and 1990 in 1,567 heterosexual intravenous drug users who had been seen at the AIDS Regional Reference Center in Palermo, Italy, to evaluate the rate of human immunodeficiency virus type 1 (HIV-1) seroprevalence in this group and its long-term trend. Sixty serum samples collected from drug users in 1980 and 1983, before the founding of the Center (1985), were tested as well. Some demographic and behavioral risk factors were studied in a subgroup of intravenous drug users enrolled in 1985, 1987, and 1990 for their possible association with HIV-1. These factors were also studied in relation to hepatitis B virus infection, since both viruses share the same modes of spread. These drug users had a higher prevalence of markers for hepatitis B virus than of HIV-1 antibodies, and the prevalence rates in sera collected declined over time for both infections. The presence of both antibodies to HIV-1 and markers for hepatitis B virus was independently associated with the age of the drug user, the duration of drug use, and the year of serum collection. Antibodies to HIV-1 were observed more frequently in females than in males. No relation was found between education or employment status and the presence of HIV-1 antibodies or hepatitis B virus markers. Although new HIV-1 infections still occur, the decline in seroprevalence observed at the end of the 1980s might be related to modifications in social behavior among newer drug users, partial exhaustion of the susceptible population, and increasing risk awareness in more experienced users.
|
|
|
|
de Villiers, M. S., Richardson, P. R. K., & van Jaarsveld, A. S. (2003). Patterns of coalition formation and spatial association in a social carnivore, the African wild dog (Lycaon pictus). J Zool, 260(4), 377–389.
Abstract: In many social species, relationships within groups seem to be non-random but related to variables such as rank, kinship or sexual attractiveness. The endangered African wild dog Lycaon pictus is a social carnivore that lives in large, stable packs, and intra-pack associations might be expected to display similar patterns. We investigated patterns of coalition formation (support during dominance interactions, and partnership interactions) and resting associations between members of a captive pack of 19 wild dogs. The social organization of the captive pack was similar to that of free-ranging packs in many respects. Polyadic (group) incidents of coalition support were also observed in a free-ranging pack. Patterns of coalition formation in the captive pack were related to rank. Most aggressive interactions involved high-ranking individuals (particularly the alpha, beta and third-ranking males) and coalitionary support tended to reinforce the existing hierarchy. However, there was at least one example of support influencing a successful rank challenge. Support was affected by potential risks and benefits, the latter including dominance through association and revolutionary alliances. An even stronger pattern overlaid associations between pack members: coalitions and resting associations were strongest between members of the same age–sex cohort, and may have enabled the eventual dominance of younger pack members over adults. Among adults, coalitionary associations were sometimes overridden by intersexual relationships. The results from this captive pack suggest that wild dogs are sensitive to differences in competitive ability. This information, in conjunction with strong affiliative bonds between littermates, is used to manoeuvre for position in the social hierarchy. It may also be important during dispersal, in encounters with other dispersing groups of the same sex. Although most features of the social structure of the captive pack were comparable to those of free-ranging packs, aspects such as the influence of relatedness on coalition formation still need to be explored.
|
|
|
|
Petit, O., & Bon, R. (2010). Decision-making processes: The case of collective movements. Behav. Process., 84(3), 635–647.
Abstract: Besides focusing on the adaptive significance of collective movements, it is crucial to study the mechanisms and dynamics of decision-making processes at the individual level underlying the higher-scale collective movements. It is now commonly admitted that collective decisions emerge from interactions between individuals, but how individual decisions are taken, i.e. how far they are modulated by the behaviour of other group members, is an under-investigated question. Classically, collective movements are viewed as the outcome of one individual's initiation (the leader) for departure, by which all or some of the other group members abide. Individuals assuming leadership have often been considered to hold a specific social status. This hierarchical or centralized control model has been challenged by recent theoretical and experimental findings, suggesting that leadership can be more distributed. Moreover, self-organized processes can account for collective movements in many different species, even in those that are characterized by high cognitive complexity. In this review, we point out that decision-making for moving collectively can be reached by a combination of different rules, i.e. individualized (based on inter-individual differences in physiology, energetic state, social status, etc.) and self-organized (based on simple response) ones for any species, context and group size.
|
|
|
|
Bonanni, R., Cafazzo, S., Valsecchi, P., & Natoli, E. (2010). Effect of affiliative and agonistic relationships on leadership behaviour in free-ranging dogs. Anim. Behav., 79(5), 981–991.
Abstract: Consensus decisions about the nature and timing of group activities allow animals to maintain group cohesiveness, but also entail costs because individuals often differ with respect to their optimal activity budgets. Two mechanisms whereby animals reach a consensus include ‘consistent leadership’, in which a single dominant individual makes the decision, and ‘variable leadership’ in which several group members contribute to the decision outcome. Sharing of consensus decisions is expected to reduce consensus costs to most group members. Both patterns are thought to emerge from the complexity of social relationships of group members. We investigated the distribution of leadership during group departures in two packs of free-ranging dogs, Canis lupus familiaris, and tested how its distribution between individuals was affected by dominance rank-related affiliative and agonistic relationships. Although leadership was not entirely concentrated on a single group member, both packs had a limited number of habitual leaders. In the largest pack, the pattern of leadership changed from ‘variable’ to nearly ‘consistent’ after its size had shrunk. Habitual leaders were usually old and high-ranking individuals. However, high-ranking dogs that received affiliative submissions in greeting ceremonies were more likely to lead than dominant dogs receiving submissions only in agonistic contexts. During resting times, habitual followers associated more closely with habitual leaders than with other followers. These results suggest that in social species collective movements may arise from the effort of subordinates to maintain close proximity with specific valuable social partners.
|
|
|
|
Sankey, C., Richard-Yris, M. - A., Henry, S., Fureix, C., Nassur, F., & Hausberger, M. (2010). Reinforcement as a mediator of the perception of humans by horses (Equus caballus). Anim. Cogn., 13(5), 753-764.
Abstract: A central question in the interspecific human/animal relationship is how domestic animals perceive humans as a significant element of their environment. In this study, we tested the hypothesis that the use of positive or negative reinforcement in horse training may have consequences on the animals’ perception of humans, as a positive, negative or neutral element. Two groups of ponies were trained to walk backwards in response to a vocal order using either positive or negative reinforcement. Heart rate monitors and behavioural observations were used to assess the animals’ perception of humans on the short (just after training) and long (5 months later) terms. The results showed that the type of reinforcement had a major effect on the subsequent animals’ perception of familiar and unfamiliar humans. Negative reinforcement was rapidly associated with an increased emotional state, as revealed by heart rate measurements and behavioural observations (head movements and ears laid back position). Its use led the ponies to seek less contact with humans. On the contrary, ponies trained with positive reinforcement showed an increased interest in humans and sought contact after training. This is especially remarkable as it was reached in a maximum of 5 sessions of 1 to 3 min (i.e. 5 to 15 min) and had lasting effects (visible after 5 months). Even learning was positively influenced by positive reinforcement. Overall, horses seem capable of associating humans to particular experiences and display extended long-term memory abilities.
|
|
|
|
Cozzi, A., Sighieri, C., Gazzano, A., Nicol, C. J., & Baragli, P. (2010). Post-conflict friendly reunion in a permanent group of horses (Equus caballus). Behav. Process., 85(2), 185–190.
Abstract: Gregarious animals living in permanent social groups experience intra-group competition. Conflicts over resources can escalate into costly aggression and, in some conditions, non-dispersive forms of conflict resolution may be favoured. Post-conflict friendly reunions, hence reconciliation, have been described in a variety of species. The aim of this study was to explore, for the first time, the occurrence of reconciliation in a group of domestic horses (Equus caballus) and learn more about strategies used to maintain group cohesion. The behaviour of seven horses living as permanent group in an enclosure for at least 2 years was observed by video for 108 h from June to August 2007. We used a Post-Conflict/Matched Control method to assess the existence of reconciliation and third-party affiliation. Behaviours recorded Post-Conflict, or during Matched Control periods, were classified as affiliative based on previous descriptions of visual communication patterns in horses. The proportion of attracted pairs over total post-conflict situations was significantly greater than the proportion of dispersed pairs, both during dyadic interactions (p < 0.001) and during triadic interactions (p = 0.002). The results of the present study show that both dyadic reconciliation and third-party post-conflict affiliative interactions form important social mechanisms for managing post-conflict situations in horses.
|
|
|
|
Mitani, J. C. (2009). Male chimpanzees form enduring and equitable social bonds. Anim. Behav., 77(3), 633–640.
Abstract: Controversy exists regarding the nature of primate social relationships. While individual primates are frequently hypothesized to form enduring social bonds with conspecifics, recent studies suggest that relationships are labile, with animals interacting only over short periods to satisfy their immediate needs. Here I use data collected over 10 years on a community of chimpanzees, Pan troglodytes, at Ngogo, Kibale National Park, Uganda, to investigate whether male chimpanzees establish long-term social relationships and to determine the factors that affect variation in relationship quality and the stability of social bonds. Kinship and dominance rank influenced the quality of relationships. Maternal brothers and males of the same dominance rank class groomed each other more equitably than did unrelated males and males that were dissimilar in rank. In addition, males that formed strong social bonds groomed more equitably than did males that displayed weaker bonds. Social bonds were stable over time, with relationships in one year predicting those in subsequent years. Kinship and the quality of social relationships affected bond stability. Maternal half siblings and males that groomed each other equitably maintained longer-lasting bonds than did nonkin and males that groomed each other unevenly. Virtually all of the males established at least one enduring relationship with another individual. The most enduring bonds formed between a few pairs of maternal brothers and dyads that maintained balanced grooming interactions. These results indicate that male chimpanzees maintain long-lasting and equitable social bonds whose formation is affected by maternal kinship and the quality of social relationships.
|
|
