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Burla, J. B., Rufener, C., Bachmann, I., Gygax, L., Patt, A., & Hillmann, E. (2015). Effect of varying dimensions of the littered lying area on the lying behaviour of group-housed horses (Equus ferus caballus). In Proceedings of the 3. International Equine Science Meeting.
Abstract: Although horses can sleep while standing, recumbency is required for REM sleep and since all sleep stages must be completed for an entire sleep cycle, the opportunity for recumbency is essential for animal welfare. Observations on feral horses indicate a minimal lying duration of 30 min, preferably on a deformable and dry ground. In contrast to feral horses, lying behaviour in stabled horses is often affected by the dimensions of the provided lying area and rank.
In Switzerland, minimum requirements (MR) for the littered lying area are established by law to ensure animal welfare (BLV, 2008) (A/N: approximately match German recommendations (BMEL, 2009)). The aim of this study was to assess the adequacy of the dimensions of the minimum requirements for group-housed horses by investigating 38 horses in 8 groups. Further, hard rubber mats were provided supplementary in order to assess their suitability as an alternative to litter. Four treatments were each applied in randomised order:
– 0x MR: no litter + 1.5x MR with rubber mats
– 0.5x MR: 0.5x MR with litter + 1x MR with rubber mats
– 1x MR: 1x MR with litter; 0.5x MR with rubber mats
– 1.5x MR: 1.5x MR with litter + no rubber mats
For each treatment, after a habituation period of 8 days, lying behaviour was recorded (video, accelerometers) continuously for 72 hrs. Statistical analysis was performed using mixed effects models.
Regardless of the ground chosen, the duration of recumbency per 24 hrs was increasing with increasing dimensions of the littered area (F1,93 = 12.9, p = 0.0005; Fig. 1). Whereas the effect flattened from 1x to 1.5x MR, the duration spent on litter – a deformable ground – was increasing continuously (F1,62 = 23.1, p < 0.0001). Further, the proportion of lateral recumbency was increased with increased dimensions of the littered area (F1,79 = 12.3, p = 0.0007). Regarding the number of lying bouts, no differences were apparent between treatments providing litter, but recumbency occurred very seldom if only rubber mats were provided (F1,93 = 14.7, p = 0.0002). Further, low-ranking horses spent more lying bouts on rubber mats than high-ranking horses (F1,29 = 4.4, p = 0.04). Additionally, the larger the dimensions of the littered area the more horses were present in the lying area at the moment of lying down (F1,79 = 6.6, p = 0.01). Moreover, low-ranking horses showed considerably higher percentages of involuntarily terminated lying bouts than high-ranking horses if 0.5x and 1x MR were littered (F1,76 = 8.43, p = 0.005).
Although the indicated minimal lying duration was averagely performed, large individual differences occurred and at least 8% were lying down less than 30 min per 24 hrs in every treatment. Further, the inclusion of social parameters indicated a beneficial effect of an exceedance of the minimum requirements especially for low-ranking horses. Therefore, the minimum requirements established by Swiss law can be stated as adequate but should be perceived as minimum and not optimum dimensions.
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Berger, A. (2015). Evaluation of living conditions in free running animals by chronobiological analysis of continuously recorded behavioural data. In Proceedings of the 3. International Equine Science Meeting.
Abstract: We developed a biorhythmical method to assess behaviour patterns and to evaluate living conditions of animals. All kinds of continuous and equidistant long-term recordings of behaviour are suitable for this method. As simple behavioural parameters, such as motor activity, can be conveniently recorded by telemetry from wild animals now, it is possible to investigate stressors by analysing its biorhythmic structure. It is the purpose of this report to describe the basic idea, and the procedure, and to give some examples of application measured on Przewalski horses in an Semireserve.
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Bouskila, A.,, Lourie, E., de Vries, H., Hermans, Z. M.., & van Dierendonck, M. (2015). Sex, but not relatedness nor age, affect the social network of horses in a semi-natural reserve. In Proceedings of the 3. International Equine Science Meeting.
Abstract: For some time now, social network analysis provides tools to describe concisely the social structure of animals. Nevertheless, the factors that shape the social network and determine the frequency of different types of affiliations are often unclear. For example, the effects of relatedness on social networks have been only studied on relatively few species. Both among social or sub-social species the effects ranged from no effect to a substantial effect. Here we test the hypothesis that relatedness has an effect on the social network of horses (Equus caballus) that live freely in semi-natural conditions, and specifically, that individuals with high values of relatedness to their neighbors in the network will have fewer links Wolf et al, 2011). This hypothesis is based on the notion that related individuals have common interests and are likely to assist each other, and may need less links to other, unrelated individuals. In addition, individuals of similar age and sex are likely to have common needs, and thus are more likely to be associated. We thus tested a second hypothesis: homophily to individuals with similar age and sex will have a role in determining the associations within the social network. The field study was conducted on 27 horses in the Blauwe Kamer reserve in the Netherlands (1.1 sq km). We videotaped horses and their groups and used the information from 22 horses, after excluding the five foals from the analysis. Relatedness was calculated from the pedigree, which was based on parentage, determined by DNA analysis. The social network was constructed based on spatial proximity data. We assessed the influence of relatedness, age-homophily and sex-homophily on the network structure with Multiple Regression Quadratic Assignment Procedure (MRQAP) (Krackhardt 1988), with the R package sna. The results show that there was no significant effect of relatedness on the network, nor an effect of age-homophily. Nevertheless, we found a significant effect of sex-homophily, the tendency of individuals to associate with individuals of the same sex. We argue that the lack of a relatedness effect is not likely to have been caused due to the inability to detect who is kin. The structured social system in horses includes strong associations between often unrelated individuals, alongside with young individuals leaving their natal harem as part of the inherent inbreeding avoidance (Linklater & Cameron 2009; Boyd et al. in press). The significant effect of sex-homophily could stem from the protection females get from associations with other females, e.g., in the reduction of harassment from males. Previous studies on feral horses showed that mares that were better connected with other females in their harem benefited from higher survival rates to their foals (Cameron et al. 2009). The associations among bachelor males could also contribute to the strength of the sex-homophily effect.
In order to generalize from our results, one needs to examine additional populations of horses, because the conditions in the Blauwe Kamer reserve may not be representative, mainly due to the limited opportunity for dispersal in a restricted area.
Keywords: Long-term affiliation; spatial proximity, kin detection
Boyd, L., Scorolli, A. L., Nowzari, H., & Bouskila, A. (2016). Chapter 2: Social organization. In J. I. Ransom, & P. Kaczensky (Eds.), Wild equids. Baltimore, Maryland (in press): The Johns Hopkins University Press.
Cameron, E. Z., Setsaas, T. H., & Linklater, W. L. (2009). Social bonds between unrelated females increase reproductive success in feral horses. Proceedings of the National Academy of Sciences, 106(33), 13850-13853
Krackhardt, D. (1988). Predicting with networks: Nonparametric multiple regression analysis of dyadic data. Social Networks, 10(4), 359-381.
Linklater, W. L., & Cameron, E. Z. (2009). Social dispersal but with philopatry reveals incest avoidance in a polygynous ungulate. Animal Behaviour, 77(5), 1085-1093.
Wolf, J. B., Traulsen, A., & James, R. (2011). Exploring the link between genetic relatedness r and social contact structure k in animal social networks. The American Naturalist, 177(1), 135-142.
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Wolter, R., & Krueger, K. (2015). The analysis of social bonds in feral horses. In Proceedings of the 3. International Equine Science Meeting.
Abstract: In many social mammals, individuals preferentially affiliate with a small subset of available partners instead of distributing their social behaviors equally among all group members. The resulting social bonds have been investigated in several mammalian taxa, especially in primate societies, but also in other taxa such as birds, dolphins, rodents and ungulates. In feral horses, a great number of studies on social bonds can be found, but with a huge variety between methods for the analysis. There seems to be a lack of a clear and common definition of social bonds in horses and of comparable analyses. For example, there are irregularities between the studies regarding the research designs, the selection of recording methods and the interpretation of the measurements. Mutual grooming is used most often for the analysis of social relationships in many species. As mutual grooming is rare in horses, especially measurements of spatial proximity are commonly used for the analysis of social bonds in addition to other behavioral patterns. However, the combination of mutual grooming and nearest neighborhood analyses for the analysis of social bond is debatable, as in contrast to mutual grooming, which must occur deliberately by both grooming partners, the spatial distribution can be influenced by one partner alone, which may even force the other horse to keep a certain distance or to stay in close proximity.
In this study, we investigated the comparability of mutual grooming and nearest neighborhood data for social bond analyses in feral horses. Therefore, we observed five groups of semi-wild living Przewalski’s horses and six groups of feral horses.
We analysed the horses’ social ranks by applying an Average Dominance Index, we recorded the distances between the animals and observed the number of mutual grooming events as well as friendly approaches.
Our results show that there was only a weak correlation between the frequency of staying in nearest neighborhood and mutual grooming in all observed horse groups. In contrast to this, the correlation between the number of friendly approaches and mutual grooming events was higher in most groups.
Hierarchies did not affect social bonds, as mutual grooming was similarly induced by higher and lower ranking animals and the social rank did not affect the choice of the grooming partner. Similarly, likelihoods of staying in the neighborhood of particular animals were not affected by the animals’ social rank.
The grooming frequencies differed between the different horse groups and between the individual horses living in the particular groups. They seem to be effected by individual predisposition.
Altogether we suggest that the ratio of mutual grooming seems to be a better indicator for social bonds in feral horses than the frequency of staying in the nearest neighborhood. Mutual grooming occurs deliberately and is bidirectional, whereas nearest neighborhoods could be enforced and unidirectional. For the calculation of social bonds in horses, we consider it to be more reliable to combine the frequency of mutual grooming with the frequency of friendly approaches.
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Krause, J., James, R., Franks, D. W., & Croft, D. P. (2015). Animal Social Networks. Oxford: Oxford University Press.
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Rubenstein D.I. (2015). Networks of terrestrial ungulates: linking form and function. In D. P. & Croft D. W. Franks R. James J. Krause (Ed.), Animal Social Networks. Oxford: Oxford University Press.
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Merola, I., Lazzaroni, M., Marshall-Pescini, S., & Prato-Previde, E. (2015). Social referencing and cat–human communication. Anim. Cogn., 18(3), 639–648.
Abstract: Cats’ (Felis catus) communicative behaviour towards humans was explored using a social referencing paradigm in the presence of a potentially frightening object. One group of cats observed their owner delivering a positive emotional message, whereas another group received a negative emotional message. The aim was to evaluate whether cats use the emotional information provided by their owners about a novel/unfamiliar object to guide their own behaviour towards it. We assessed the presence of social referencing, in terms of referential looking towards the owner (defined as looking to the owner immediately before or after looking at the object), the behavioural regulation based on the owner’s emotional (positive vs negative) message (vocal and facial), and the observational conditioning following the owner’s actions towards the object. Most cats (79 %) exhibited referential looking between the owner and the object, and also to some extent changed their behaviour in line with the emotional message given by the owner. Results are discussed in relation to social referencing in other species (dogs in particular) and cats’ social organization and domestication history.
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Defolie, C., Malassis, R., Serre, M., & Meunier, H. (2015). Tufted capuchins (Cebus apella) adapt their communicative behaviour to human’s attentional states. Anim. Cogn., 18(3), 747–755.
Abstract: Animal communication has become a widely studied field of research, especially because of the associated debates on the origin of human language. Due to their phylogenetic proximity with humans, non-human primates represent a suitable model to investigate the precursors of language. This study focuses on the perception of the attentional states of others, an important prerequisite to intentional communication. We investigated whether capuchins (Cebus apella) produce a learnt pointing gesture towards a hidden and unreachable food reward as a function of the attentional status of the human experimenter. For that purpose, we tested five subjects that we first trained to indicate by a pointing gesture towards the human partner the position of a reward hidden by an assistant. Then, capuchins were tested in two experimental conditions randomly ordered. In the first condition—motivation trial—the experimenter was attentive to the subject gestures and rewarded him immediately when it pointed towards the baited cylinder. During the second condition—test trial—the experimenter adopted one of the following attention states and the subject was rewarded after 10 s has elapsed, regardless of the subject’s behaviour. Five attentional states were tested: (1) experimenter absent, (2) experimenter back to the monkey, (3) experimenter’s head away, (4) experimenter watching above the monkey, and (5) experimenter watching the monkey face. Our results reveal a variation in our subjects’ communicative behaviours with a discrimination of the different postural clues (body and head orientation) available in our experimental conditions. This study suggests that capuchins can flexibly use a communicative gesture to adapt to the attentional state of their partner and provides evidence that acquired communicative gestures of monkeys might be used intentionally.
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Oliva, J. L., Rault, J. - L., Appleton, B., & Lill, A. (2015). Oxytocin enhances the appropriate use of human social cues by the domestic dog (Canis familiaris) in an object choice task. Anim. Cogn., 18(3), 767–775.
Abstract: It has been postulated that the neuropeptide, oxytocin, is involved in human–dog bonding. This may explain why dogs, compared to wolves, are such good performers on object choice tasks, which test their ability to attend to, and use, human social cues in order to find hidden food treats. The objective of this study was to investigate the effect of intranasal oxytocin administration, which is known to increase social cognition in humans, on domestic dogs’ ability to perform such a task. We hypothesised that dogs would perform better on the task after an intranasal treatment of oxytocin. Sixty-two (31 males and 31 females) pet dogs completed the experiment over two different testing sessions, 5–15 days apart. Intranasal oxytocin or a saline control was administered 45 min before each session. All dogs received both treatments in a pseudo-randomised, counterbalanced order. Data were collected as scores out of ten for each of the four blocks of trials in each session. Two blocks of trials were conducted using a momentary distal pointing cue and two using a gazing cue, given by the experimenter. Oxytocin enhanced performance using momentary distal pointing cues, and this enhanced level of performance was maintained over 5–15 days time in the absence of oxytocin. Oxytocin also decreased aversion to gazing cues, in that performance was below chance levels after saline administration but at chance levels after oxytocin administration.
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Takaoka, A., Maeda, T., Hori, Y., & Fujita, K. (2015). Do dogs follow behavioral cues from an unreliable human? Anim.Cogn., 18(2), 475–483.
Abstract: Dogs are known to consistently follow human pointing gestures. In this study, we asked whether dogs “automatically” do this or whether they flexibly adjust their behavior depending upon the reliability of the pointer, demonstrated in an immediately preceding event. We tested pet dogs in a version of the object choice task in which a piece of food was hidden in one of the two containers. In Experiment 1, Phase 1, an experimenter pointed at the baited container; the second container was empty. In Phase 2, after showing the contents of both containers to the dogs, the experimenter pointed at the empty container. In Phase 3, the procedure was exactly as in Phase 1. We compared the dogs’ responses to the experimenter’s pointing gestures in Phases 1 and 3. Most dogs followed pointing in Phase 1, but many fewer did so in Phase 3. In Experiment 2, dogs followed a new experimenter’s pointing in Phase 3 following replication of procedures of Phases 1 and 2 in Experiment 1. This ruled out the possibility that dogs simply lost motivation to participate in the task in later phases. These results suggest that not only dogs are highly skilled at understanding human pointing gestures, but also they make inferences about the reliability of a human who presents cues and consequently modify their behavior flexibly depending on the inference.
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