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Fischhoff, I. R., Sundaresan, S. R., Cordingley, J., Larkin, H. M., Sellier, M. - J., & Rubenstein, D. I. (2007). Social relationships and reproductive state influence leadership roles in movements of plains zebra, Equus burchellii. Anim. Behav., 73(5), 825–831.
Abstract: In animal groups, collective movements emerge from individual interactions. Biologists seek to identify how characteristics of actors in these groups, and their relationships, influence the decision-making process. We distinguished two basic factors determining leadership in group choices: identity and state. We hypothesized that identity is more important to leadership in groups with stable relationships, which permit the development of habitual roles. In groups with fluid membership, particular individuals or subgroups are less likely to emerge as consistent leaders. Instead, we predicted that movement initiation in unstable groups depends on individual state at the time of the decision. We characterized how identity and reproductive state influenced leadership patterns in the movements of plains zebra. As in many other mammals, lactation in this species significantly alters water and energy needs. We investigated leadership in tightly knit harems and loosely bonded herds of multiple harems. Harem females tended to have habitual roles in the initiation of harem movement. In herds, however, we found no consistent leaders among harems. At both levels of social organization, lactation was a key determinant of leadership. In harems, lactating females were more likely to initiate movement than nonlactating females. In turn, harems containing lactating females were more likely to lead herd movements. Thus, we conclude that social relationships and reproductive state together shape the interactions that produce group behaviours. One benefit to lactating females of leading herd movements is preferential access to scarce water. Thus, leadership roles in group decisions may have fitness consequences.
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Lloyd, A. S., Martin, J. E., Bornett-Gauci, H. L. I., & Wilkinson, R. G. (2007). Evaluation of a novel method of horse personality assessment: Rater-agreement and links to behaviour. Appl. Anim. Behav. Sci., 105(1-3), 205–222.
Abstract: The efficacy of questionnaire-based personality assessment has been shown in a variety of animal and human personality studies. There has been a recent increase in questionnaire-based studies focussing on equine personality but with a lack of comparability to studies on other species. The aim of this study was to test the reliability of an assessment method originally developed for primates and demonstrate reliability using three criteria (1) assessments by independent observers must agree with one another, (2) these assessments must predict behaviours and real-world outcomes and (3) observer ratings must be shown to reflect genuine attributes of the individuals rated, not merely the observer's implicit personality theories about how traits co-vary. The personality of 61 horses (Equus caballus) was assessed using a questionnaire constructed of 30 behaviourally defined adjectives (BDAs). Horses were each assessed by three judges, in addition to a total of 2 h behaviour observations recorded per horse. Rater agreement was demonstrated for 72.1% of the horses and 25 of the BDAs. Principal component analysis was carried out on the rating data and revealed six underlying personality components that were labelled “dominance”, “anxiousness”, “excitability”, “protection”, “sociability” and “inquisitiveness”. Component scores for horses were correlated against behavioural observations for the same horses and revealed significant correlations with 20 of the recorded behaviour variables. Correlations between specific components and their associated behaviours were logical and consistent with the types of behaviours that would be expected to be linked with such personality types. The data were shown to meet all three criteria and provided strong evidence that the assessment method was reliably measuring horse personality.
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Vervaecke, H., Stevens, J., Vandemoortele, H., Sigurjönsdöttir, H., & De Vries, H. (2007). Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus). J. Ethol., 25(3), 239–248.
Abstract: Abstract We studied sex differences in the nature of aggression and dominance behaviour in two newly formed groups of 1-year-old Icelandic horses. One herd contained nine geldings, the other nine mares. The groups were matched with regard to dominance-determining traits such as age, weaning age, composition of native herd, social experience, genetic origin, body condition and maternal dominance status. High-ranking individuals of both sexes were more aggressive, high-ranking males were older, and high-ranking females had a better body condition. Frequencies of aggressions were similar in both groups. The mares reacted significantly more by showing submission upon an aggression rather than by not responding or by escalating the aggression. For the geldings, this difference was not observed due to a lower tendency to submit. A linear dominance hierarchy was found in both groups. David`s scores provided additional information regarding cardinal rank distances and were used to calculate steepness of hierarchies. The female hierarchy was somewhat steeper compared to the male hierarchy, suggesting somewhat lower despotism among males. This was mainly a consequence of the lower unidirectionality in male submission. Male contests occurred predominantly between dyads at top and mid positions, suggesting a low degree of acceptance of the hierarchy.
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King, S. R. B., & Gurnell, J. (2007). Scent-marking behaviour by stallions: an assessment of function in a reintroduced population of Przewalski horses (Equus ferus przewalskii). J Zool, 272(1), 30–36.
Abstract: Abstract Scent marking is a common form of intraspecific communication in mammal species, and using faeces or urine is a cost-effective way of signalling competitive ability and resource holding power. Marking is ritually performed by male equids, and here we assess the function of male scent-marking behaviour in a recently introduced population of Przewalski horses Equus ferus przewalskii in Mongolia. Two forms of scent marking were observed: defecation on stud piles formed from repeated dunging in the same place, and overmarking of faeces and urine of mares. Stud piles were marked with dung by the harem holder and sniffed before and after dung was deposited. They were not found specifically at the periphery of harem ranges but occurred for the most part along routes used by the horses, and were more common in the core parts of harem ranges or where harem ranges overlapped. Thus, rather than being used to defend range boundaries, stud piles were placed predominantly where they would be encountered by male intruders. Mare excreta were covered with urine by the stallion, but were only sniffed before they were marked, not after. These marks appear to advertise to the mare and other, intruding stallions that the harem holder was the mare's consort and that the interloper should not risk trying to steal the mare or sneak a mating. Thus, the two forms of marking by harem holders appear to combine as first and second lines of defence of paternity rights in male intrasexual competition.
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Kulikova, E. E., Isaeva, A. S., Rotkina, A. S., Manykin, A. A., & Letarov, A. V. (2007). Diversity and dynamics of bacteriophages in horse feces. Microbiology, 76(2), 271–278.
Abstract: The complex cellulolytic microbial community of the horse intestines is a convenient model for studying the ecology of bacteriophages in natural habitats. Unlike the rumen of the ruminants, this community of the equine large intestine is not subjected to digestion. The inner conditions of the horse gut are much more stable in comparison to other mammals, due to the fact that the horse diet remains almost unchanged and the intervals between food consumption and defecation are much shorter than the whole digestive cycle. The results of preliminary analysis of the structure and dynamics of the viral community of horse feces, which combines direct and culture methods, are presented. In horse fecal samples, we detected more than 60 morphologically distinct phage types, the majority of which were present as a single phage particle. This indicates that the community includes no less than several hundreds of phage types. Some phage types dominated and constituted 5-11% of the total particle count each. The most numerous phage type had an unusual morphology: the tails of its members were extremely long (about 700 nm), flexible, and irretractable, while their heads were 100 nm in diameter. Several other phage types with similar but not identical properties were detected. The total coliphage plaque count of the samples taken from three animals revealed significant fluctuations in the phage titers. During the observation time, the maximum titer ranged within four orders of magnitude (10(3)-10(7) plaque forming units (PFU)/g); the minimum titer ranged within two orders of magnitude. The samples contained two to five morphologically distinct and potentially competitive coliphage types, specific to a single Escherichia coli strain.
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Nogueira, S. S. da C., Nogueira-Filho, S. L. G., Bassford, M., Silvius, K., & Fragoso, J. M. V. (2007). Feral pigs in Hawai`i: Using behavior and ecology to refine control techniques. Appl. Anim. Behav. Sci., 108(1-2), 1–11.
Abstract: Early Polynesians settlers were the first to introduce pigs to the Hawaiian Islands. Later Captain Cook brought European pigs during his first voyage to Hawai`i. Many other importations have followed. Animals from these introductions became feral and dispersed throughout the islands. Free-ranging pigs are now considered pests with negative impacts on some native biota. Several methods to control the ecological damage attributed to pigs have been adopted, such as fencing, hunting, live trapping and poisoning. However, the absence of behavioral knowledge in current control programs has resulted in inefficient management of this species. Therefore, the feral pig problem continues, and what before was almost strictly an agricultural and conservation concern has now become an urban problem as well. The aim of this study is to describe the state of knowledge on feral pig behavior in the Hawaiian Islands, introducing potential management approaches derived from the principles of behavioral ecology. Considering behavioral aspects of feral pig ecology, such as cognition and communication could help improve capture techniques, keep feral pigs away from urban areas and begin to resolve human-wildlife conflicts.
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Watanabe, S. (2007). How animal psychology contributes to animal welfare. Appl. Anim. Behav. Sci., 106(4), 193–202.
Abstract: This article explores the contribution of animal psychology to animal welfare. Since animal welfare includes subjective welfare, it is crucial to know the subjective world of animals. Analysis of the concept of anthropomorphism is particularly important because it is a basic idea of animal ethics. The history of animal psychology, focusing on anthropomorphism and behaviourism, is briefly described, and then measurement of the subjective experience of animals in two ways, namely animal cognition and pleasure or reinforcing effects, is reported. Finally, it is suggested that animal welfare is not a permanently fixed idea, but a socially constructed one that can be changed. To gain widespread agreement about a socially constructed idea, it is important to know in which circumstances ordinary people employ metaphorical extension to an understanding of animal behaviour. In other words, a survey of “folk animal psychology” is important in order to establish a consensus about animal welfare.
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Gifford, A. K., Cloutier, S., & Newberry, R. C. (2007). Objects as enrichment: Effects of object exposure time and delay interval on object recognition memory of the domestic pig. Appl. Anim. Behav. Sci., 107(3-4), 206–217.
Abstract: A modified spontaneous object recognition test was used to examine object recognition memory in the domestic pig. This test uses preference for a novel object over a previously encountered sample object as indicating recognition of the sample object, and no preference as indicating no recognition. Two factors hypothesized to affect object recognition are duration of exposure to the sample stimulus and delay interval before re-exposure. Both of these factors could be manipulated in a rotational object enrichment program for pigs. Reducing exposure time and increasing the delay interval before re-exposure should decrease object recognition and prolong novelty-induced object exploration. We exposed 5-week-old pigs to different sample objects in their home pens for 10 min and 2 days, respectively. We tested for object recognition memory at various delay intervals after initial exposure by placing littermate pairs in a test pen for 10 min and recording snout contact with a sample object and a completely novel object. At a 1-h delay, half the pairs were tested with the 2-day sample object; the other half received the 10-min sample object. At a 3-h delay, pairs were tested with the opposite sample object. Pairs were also tested with the 2-day sample at a 5-day delay and the 10-min sample at a 6-day delay. We predicted that pigs would show a preference for the novel versus the 2-day sample object at all three delays, but would only prefer the novel object over the 10-min sample object at the 1-h and 3-h delays. Pigs did not show novelty preference in the presence of the 10-min sample object at any delay. Novelty preference in the presence of the 2-day sample object occurred at the 3-h (P < 0.05) and 5-day delays (P < 0.001), but not the 1-h delay. The lack of novelty preference when pigs were tested with the 10-min sample object may have been due to failure to habituate to the sample object. Testing in a different location from the initial sample object exposure and retroactive interference from exposure to the 10-min sample object may have contributed to a temporary lack of novelty preference when pigs were tested with the 2-day sample object at the 1-h delay. The finding that pigs retained a memory for the 2-day sample object for at least 5 days suggests that restricting object exposure to less than 2 days may help to preserve the exploratory value of objects rotated among pens.
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Penn, D. C., & Povinelli, D. J. (2007). Causal Cognition in Human and Nonhuman Animals: A Comparative, Critical Review. Annual Review of Psychology, 58(1), 97–118.
Abstract: In this article, we review some of the most provocative experimental results to have emerged from comparative labs in the past few years, starting with research focusing on contingency learning and finishing with experiments exploring nonhuman animals' understanding of causal-logical relations. Although the theoretical explanation for these results is often inchoate, a clear pattern nevertheless emerges. The comparative evidence does not fit comfortably into either the traditional associationist or inferential alternatives that have dominated comparative debate for many decades now. Indeed, the similarities and differences between human and nonhuman causal cognition seem to be much more multifarious than these dichotomous alternatives allow.
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Pain, S. (2007). Inner Representations and Signs in Animals. In Introduction to Biosemiotics (pp. 409–455).
Abstract: At the beginning of the twentieth century, behaviourists like John B. Watson (1878-1958) changed the focus of attention from the inside of the brain (mentalism and introspection then being the main trend in psychology at the time) to the outside (Watson, 1913). They believed that we could learn nearly everything about animals and humans by studying their performance in learning experiments, and this was both measurable and verifiable. Today in the first decade of the twenty-first century, there has been a return to the inside. The neurosciences seek physiological explanations and connections between external behaviour and the neural mechanisms within the nervous system. With the revolution in magnetic resonance imaging (MRI) technology researchers are now able to visually represent neural activity. Other researchers have developed mathematical models and programs to visualise the patterns created in the periphery prior to central integration The author in this paper would like to distinguish these descriptive forms of representation from actual representations, i.e., those of which the animal is actually aware or conscious. Why does an animal sometimes make perceptual mistakes? (Case Study I “The Turtle and the Plastic Bag”). Is there more to dispositions? (Case Study II: “Taking Representation for a Walk. Argos and the Fake Daniel Dennett”). How is prey represented to an animal? (Case Study III “Representation of Prey in the Jellyfish/Herring Predator-Prey Dyad”). Does a simple animal feel pain or suffer? (Case Study IV: A Can of Worms. The Earthworm as Bait) It will be argued on the basis of contemporary biosemiotic research that animals (including both vertebrates and invertebrates) represent environmental information internally, and these representations can be subdivided into i.) primary or peripheral representation and ii.) central representation which are quantitative and qualitative respectively. Sensory information is conveyed via signals, these are received as stimuli then transduced into internal signals (see Theoretical Framework). At this stage the animal is not aware of the quality of the information as it has not yet been integrated or processed in a ganglionic complex. One can describe the properties of this pre-integrated information as quantitative and syntactical i.e., spatial and temporal ordering of incoming signals and their relations. The sign which is the smallest unit of qualitative representation arises only after integration of information from two or more discrete sensory modalities. These findings have repercussions for current models of animal learning and behaviour, especially in lower invertebrates (the principal subject of this paper); they also challenge the development of robots based on so-called simple systems
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