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Joubert, E., & Louw, G. N. (1976). Preliminary observations on the digestive and renal efficiency of Hartmann's zebra Equus zebra hartmannae. Madoqua, 10, 119–121.
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Galef Jr B.G.,. (2004). Approaches to the study of traditional behaviors of free-living animals. Learn. Behav., 32, 53–61.
Abstract: I review literature on four different approaches to the study of traditions in animals: observation of free-living animals, laboratory experiment, armchair analysis, and field experiment. Because, by definition, a tradition entails social learning of some kind, it is difficult, perhaps impossible, to establish that a behavior is in fact traditional without knowledge of how it develops. Observations of free-living animals often provide strong circumstantial evidence of a tradition. However, even in the view of several researchers who have studied possibly traditional behaviors in natural populations, observation alone has not proven sufficient to show that social learning contributes to development of behaviors of interest. The relevance of laboratory experiments to the understanding of the development of behaviors in free-living animals is always open to challenge. Armchair analyses of field data can produce interesting hypotheses but cannot test them. Field experiments to determine how behaviors of interest develop in population members provide a promising way forward.
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Gajdon G.K.,, Fijn N.,, & Huber L.,. (2004). Testing social learning in a wild mountain parrot, the kea (Nestor notabilis). Learn. Behav., 32, 62–71.
Abstract: Huber, Taborsky, and Rechberger (2001) reported an experiment in which the efficiency with which captive keas opened a complex food container was increased by observation of a skilled conspecific. However, only testing social learning in free-ranging animals can demonstrate social learning in natural conditions. For that purpose, a tube-lifting paradigm was developed and tested on keas both in captivity and in Mount Cook National Park, New Zealand. The task was to remove a tube from an upright pole in order to gain access to a reward inside the tube. The top of the pole was higher than a standing kea, so that, to remove the tube, an individual had to simultaneously climb onto the pole and manipulate the tube up the pole with its bill. Because only 1 naive bird managed to remove a tube twice in 25 halfhour sessions and disappeared after success, another bird was trained to solve the task and to provide demonstrations for others. Even under such conditions, only 2 of at least 15 birds learned to remove the tube in 28 sessions. There was no indication that observer birds' use of bill and feet when exploring the tube changed as the number of observations of tube removal increased in a way that would, in principle, increase the likelihood of tube removal. The results suggest a dissociation of social learning potential as assessed in laboratory animals, and social transmission of foraging techniques in natural populations.
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Westergaard, G. C., Suomi, S. J., & Higley, J. D. (2002). Handedness is associated with immune functioning and behavioural reactivity in rhesus macaques. Laterality, 7(4), 359–369.
Abstract: In the present study we examined the relationship among handedness, immune functioning, and behavioural reactivity in rhesus macaques. We used the absolute number of CD4+ (T-helper) and CD8+ (T-suppressor) cells as dependent measures of immune functioning. We derived reactivity profiles from behavioural responses to a threat, and hand preference profiles from a quadrupedal food-reaching test. The results indicate positive correlations between the frequency of right versus left hand reaches and the absolute number of CD4+ cells, and between the frequency of right versus left hand reaches and the degree of human-directed aggression in response to an invasive threat. Immune measures were not associated with the strength of hand preference. These results are consistent with and extend previous findings obtained with rodents to nonhuman primates and provide further support for the view that behavioural lateralisation is associated with immune functioning and behavioural reactivity.
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Osman, F., Zeitler-Feicht, M., Fink, G. W., Arnhard, S., & Krüger, K. (2020). Überprüfung der lichten Weiten von Gitterstäben in der Pferdehaltung [Analysing demands for the clear widths of lattice bars in horse husbandry]. Landtechnik [Agricultural Engineering], 75(1), 24–33.
Abstract: An Gitterstäben, die in der Pferdehaltung an verschiedenen Stellen verwendet werden, können sich Pferde verletzen, wenn sie ihre Köpfe oder ihre Hufe hindurchstecken und nicht zurückziehen können. Um das Verletzungsrisiko zu reduzieren sind lichte Weiten und Materialstärken von Gitterstäben so zu wählen, dass Pferdeköpfe und -hufe entweder nicht zwischen den Freiräumen hindurchpassen oder aber gefahrlos wieder zurückgezogen werden können. Die bisherige Forschung liefert jedoch keine belastbaren Aussagen zu Stababständen (senkrecht und waagerecht), die für Pferde ungefährlich sind. Die in der Praxis verwendeten und in der Literatur empfohlenen Gitterstababstände beruhen auf Erfahrungswerten und technischen Materialeigenschaften. In der vorliegenden Untersuchung wurden Pferdeköpfe und -hufe von insgesamt 480 Pferden (233 Stuten, 204 Wallache und 43 Hengste) von 23 verschiedenen Rassen vermessen, um auf Grundlage der Anatomie der Pferde Aussagen über die Eignung von marktüblichen Stababständen in der Praxis treffen zu können. Es stellte sich heraus, dass bei senkrechten Gitterstäben eine lichte Weite von nicht mehr als 5 cm für alle Pferde ab einem Stockmaß von 110 cm und einem Alter von zwei Jahren als sicher bezeichnet werden kann. Bei waagerechten Gitterstäben erwies sich eine lichte Weite von genau 17 cm als sicher. Dies gilt für alle Pferde ab einem Alter von zwei Jahren oder ab einem Stockmaß von 148 cm.
Kritisch sind die lichten Weiten von Panels zu beurteilen. Hier zeigte sich, dass die handelsüblichen Abstände der Gitterstäbe für die meisten Pferde eine erhebliche Gefahr darstellen. Wenn die Pferde beispielsweise versuchen außerhalb der Panels zu fressen und dabei ihren Kopf durch die Gitterstäbe stecken, kann es leicht passieren, dass sie sich mit dem Kopf zwischen den Gitterstäben verklemmen. [At bars, used in various places in horse husbandry, horses can hurt themselves when retracting their heads or hooves after pushing them through the interspaces. In order to reduce the risk of injury, the clear widths and material thicknesses of bars should be chosen so that horse heads and hooves either cannot pass between the spaces or can be retracted safely. However, research to date has not provided any reliable information on bar width (vertical and horizontal) that is safe for horses. Grid bar width used in practice and recommended in the literature is based on empirical values and technical material properties. In this study, heads and hooves of 480 horses (233 mares, 204 geldings and 43 stallions) of 23 breeds were measured for making statements about the suitability of standard bar width, when considering the anatomy of the horse. It turned out that for vertical bars, an interspace of no more than five centimetres can be considered to be safe for all horses of a height of 110 centimetres and an age of two years and more. With horizontal lattice bars, a clear width of exactly 17 centimetres proved to be safe. This applies to all horses of a height of 148 centimetres and an age of two years or more. The clear widths of panels must be considered critical for horse welfare. When horses, for example, try to eat outside the panels and put their head through the bars, they may get stuck.] |
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Judge, P. G., de Waal, F. B., Paul, K. S., & Gordon, T. P. (1994). Removal of a trauma-inflicting alpha matriline from a group of rhesus macaques to control severe wounding. Lab Anim Sci, 44(4), 344–350.
Abstract: Wounding in an 83-member group of rhesus macaques (Macaca mulatta) housed at the Yerkes Regional Primate Research Center Field Station became excessive to the point that intervention was deemed necessary. When observations indicated that three females from the group's alpha matriline were principally responsible for the wounding, the matriline (N = 7) was removed from the group. This study was conducted to document an atypical pattern of wounding in this group and to evaluate the effectiveness of removal as a procedure for controlling injuries. The aggression rates of 21 adult subjects and the wounds of all group members were recorded before and after the removal procedure and compared with those in a similar-sized group. Removing the alpha matriline did not alter aggression rates in the group or the rank order among the remaining matrilines. Aggression rates in the experimental group were also not significantly different from those in the comparison group before or after the removal. With the alpha matriline present, wounding levels in the group were significantly higher than those in the comparison group. After removal of the matriline, the frequency of wounds decreased significantly to levels similar to those of the comparison group. The pattern of excess wounding attributed to the extracted alpha females was idiosyncratic, involving removal of large patches of skin from the hindquarters of adult females or removal of the distal portion of the fingers, toes, or tail from juveniles.(ABSTRACT TRUNCATED AT 250 WORDS)
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van Duyne, C., Ras, E., de Vos, A. E. W., de Boer, W. F., Henkens, R. J. H. G., & Usukhjargal, D. (2009). Wolf Predation Among Reintroduced Przewalski Horses in Hustai National Park, Mongolia. Journal of Wildlife Management, 73(6), 836–843.
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Guidi, A., Lanata, A., Valenza, G., Scilingo, E. P., & Baragli, P. (2017). Validation of smart textile electrodes for electrocardiogram monitoring in free-moving horses. J. Vet. Behav., 17, 19–23.
Abstract: This article focuses on the validation of smart textile electrodes used to acquire electrocardiogram (ECG) signals in horses in a comfortable and robust manner. The performance of smart textile electrodes is compared with standard Ag/AgCl electrodes in terms of the percentage of motion artifacts (MAs, the noise that results from the movement of electrodes against the skin) and signal quality. Seven healthy Standardbred mares were equipped with 2 identical electronic systems for the simultaneous collection of ECGs. One system was equipped with smart textile electrodes, whereas the second was equipped with standard Ag/AgCl electrodes. Each horse was then monitored individually in a stall for 1 hour, without any movement constraints. The ECGs were visually examined by an expert who blindly labeled the ECG segments that had been corrupted by MAs. Finally, the percentage of MAs (MA%) was computed as the number of samples of the corrupted segments over the whole length of the signal. The total MA% was found to be lower for the smart textiles than for the Ag/AgCl electrodes. Consistent results were also obtained by investigating MAs over time. These results suggest that smart textile electrodes are more reliable when recording artifact-free ECGs in horses at rest. Thus, improving the acquisition of important physiological information related to the activity of the autonomic nervous system, such as heart rate variability, could help to provide reliable information on the mood and state of arousal of horses.
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James, R., Bennett, P. G., & Krause, J. (2004). Geometry for mutualistic and selfish herds: the limited domain of danger. J. Theor. Biol., 228(1), 107–113.
Abstract: We present a two-dimensional individual-based model of aggregation behaviour in animals by introducing the concept of a “limited domain of danger”, which represents either a limited detection range or a limited attack range of predators. The limited domain of danger provides a suitable framework for the analysis of individual movement rules under real-life conditions because it takes into account the predator's prey detection and capture abilities. For the first time, a single geometrical construct can be used to analyse the predation risk of both peripheral and central individuals in a group. Furthermore, our model provides a conceptual framework that can be equally applied to aggregation behaviour and refuge use and thus presents a conceptual advance on current theory that treats these antipredator behaviours separately. An analysis of individual movement rules using limited domains of danger showed that the time minimization strategy outcompetes the nearest neighbour strategy proposed by Hamilton's (J. Theor. Biol. 31 (1971) 295) selfish herd model, whereas a random strategy confers no benefit and can even be disadvantageous. The superior performance of the time minimization strategy highlights the importance of taking biological constraints, such as an animal's orientation relative to its neighbours, into account when searching for efficient movement rules underlying the aggregation process.
Keywords: Aggregation; Selfish herd; Limited domains
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Parker, G. A. (1974). Assessment strategy and the evolution of fighting behaviour. J. Theor. Biol., 47(1), 223–243.
Abstract: The view is examined that the adaptive value of conventional aspects of fighting behaviour is for assessment of relative RHP (resource holding power) of the combatants. Outcomes of aggressive disputes should be decided by each individual's fitness budget available for expenditure during a fight (determined by the fitness difference between adoption of alternative strategies, escalation or withdrawal without escalation) and on the rate of expenditure of the fitness budget if escalation occurs (determined by the RHPs of the combatants). Thus response thresholds for alternative strategies (“assessments”) will be determined by natural selection on a basis of which opponent is likely to expend its fitness budget first, should escalation occur. This “loser” should retreat (before escalation) and the winner should stay in possession of the resource. Many aggressive decisions depend on whether one is a resource holder, or an attacker. Assuming the RHP of the combatants to be equal, there are many instances of fitness pay-off imbalances between holder and attacker which should weight the dispute outcome in favour of one or other opponent by allowing it a greater expendable fitness budget. Usually the weighting favours the holder; the attacker therefore needs a correspondingly higher RHP before it may be expected to win. This is not invariably the case, and much observed data fits the predictions of this sort of model. If assessments are perfect and budget expenditure rates exactly predictable, then there would never seem to be any case for escalation. Escalation can be explained in terms of injury inflictions (expenditures) occurring as discrete events; i.e. as “bouts” won or lost during fighting. Assessment can give only a probabilistic prediction of the outcome of a bout. A simple model is developed to investigate escalation situations. Each combatant assesses relative RHP; this correlates with an absolute probability of winning the next bout (cabs). The stake played for is infliction of loss of RHP and is determined by the fitness budgets of the opponents. (Each individual plays for the withdrawal of its opponent.) This defines a critical probability of winning (ccrit) for each combatant, above which escalation is the favourable strategy (cabs > ccrit) and below which withdrawal is favourable (cabs < ccrit). Escalation should occur only where cabs-ccrit is positive for both combatants. This model gives predictions compatible with the observations, indicating that RHP loss alone can be adequate to explain withdrawal: escalation behaviour. Withdrawal tendency will be increased by low searching costs. Escalations should be restricted to closely matched RHP opponents if RHP disparity is the major imbalance. Outside the “escalation range” of a given individual, the higher RHP individual wins and the lower one loses (i.e. it should withdraw after conventional display). RHP disparity and holder: attacker imbalance should both interact to shape the observed pattern, though their relative importances will depend on species and situation. In some instances selection may favour immediate withdrawal from an occupied territory even without assessment of RHP.
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