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Author Rizhova, L.Y.; Kulagin, D.A.
Title The effects of corticosteroids on lateral bias in female rats Type Journal Article
Year 1994 Publication (down) Behavioural Brain Research Abbreviated Journal Behav. Brain. Res.
Volume 60 Issue 1 Pages 51-54
Keywords Corticosterone; Lateral preference; Estrus cycle; Asymmetry
Abstract In Experiment 1 female rats were given one trial per day for 8 days in a T-maze, and their initial direction of choice (left/right) was noted. Vaginal smears were also obtained daily. After this some animals were adrenalectomized and given Ringer's solution; others were adrenalectomozed and given hydrocortisone replacement; a third group was sham adrenalectomized, and a fourth group was an intact control. A week after surgery the animals were again tested for 8 days in the T-maze and vaginal smears were obtained. In Experiment 2 rats were subjected to the same surgical treatments as described above and were then tested for 8 days in the T-maze. In Expt. 1 there was no direction bias among the four groups prior to surgery. However, after surgery the Adrenalectomy + Ringer's group showed a significant increase in their rightward choices in the T-maze. This was also found in Expt. 2. Both adrenalectomized groups in Expt. 1 had a significant reduction in the duration of the estrus phase of their cycle. We conclude that corticosterone can affect lateral preference in a T-maze through a mechanism independent of the hormonal changes involved in the estrus cycle.
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ISSN 0166-4328 ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5349
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Author Versace, E.; Morgante, M.; Pulina, G.; Vallortigara, G.
Title Behavioural lateralization in sheep (Ovis aries) Type Journal Article
Year 2007 Publication (down) Behavioural Brain Research Abbreviated Journal Behav. Brain. Res.
Volume 184 Issue 1 Pages 72-80
Keywords Lateralization; Laterality; Brain asymmetry; Hemisphere; Sheep; Lamb; Strength of lateralization
Abstract This study investigates behavioural lateralization in sheep and lambs of different ages. A flock was tested in a task in which the animals were facing an obstacle and should avoid it on either the right or left side to rejoin flock-mates (adult sheep) or their mothers (lambs). A bias for avoiding the obstacle on the right side was observed, with lambs apparently being more lateralized than sheep. This right bias was tentatively associated with the left-hemifield laterality in familiar faces recognition which has been documented in this species. Differences between adult sheep and lambs were likely to be due to differences in social reinstatement motivation elicited by different stimuli (flock-mates or mothers) at different ages. Preferential use of the forelegs to step on a wood-board and direction of jaw movement during rumination was also tested in adult animals. No population bias nor individual-level lateralization was observed for use of the forelegs. At the same time, however, there was a large number of animals showing individual-level lateralization for the direction of jaw movement during rumination even though there was no population bias. These findings highlight that within the same species individual- and population-level lateralization can be observed in different tasks. Moreover, the results fit the general hypothesis that population-level asymmetries are more likely to occur in tasks that require social coordination among behaviourally asymmetric individuals.
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ISSN 0166-4328 ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 6701
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Author Matsumura, S.; Kobayashi, T.
Title A game model for dominance relations among group-living animals Type Journal Article
Year 1998 Publication (down) Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.
Volume 42 Issue 2 Pages 77-84
Keywords Dominance – Hawk-dove games – Resource-holding potential – Asymmetry – Evolutionarily stable strategy
Abstract Abstract   We present here an attempt to understand behaviors of dominant individuals and of subordinate individuals as behavior strategies in an asymmetric “hawk-dove” game. We assume that contestants have perfect information about relative fighting ability and the value of the resource. Any type of asymmetry, both relevant to and irrelevant to the fighting ability, can be considered. It is concluded that evolutionarily stable strategies (ESSs) depend on the resource value (V), the cost of injury (D), and the probability that the individual in one role will win (x). Different ESSs can exist even when values of V, D, and x are the same. The characteristics of dominance relations detected by observers may result from the ESSs that the individuals are adopting. The model explains some characteristics of dominance relations, for example, the consistent outcome of contests, the rare occurrence of escalated fights, and the discrepancy between resource holding potential (RHP) and dominance relations, from the viewpoint of individual selection.
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5102
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Author Cloutier, S.; Newberry, R.C.
Title Differences in skeletal and ornamental traits between laying hen cannibals, victims and bystanders Type Journal Article
Year 2002 Publication (down) Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 77 Issue 2 Pages 115-126
Keywords Domestic fowl; Asymmetry; Skeletal traits; Comb size; Cannibalism
Abstract We compared the size of skeletal and ornamental traits, and asymmetries in bilateral skeletal traits, between victims of cannibalism, cannibals and bystanders within small groups of caged female White Leghorns at the time of cannibalistic attacks (i.e. injurious pecks resulting in bleeding). We hypothesised that victims of cannibalism have discernible morphological traits that predispose them to cannibalistic attack. We predicted that victims would have smaller skeletal traits (body length, ulna length, metatarsus length and width, toe length), lower body weight, poorer body condition, smaller combs and more asymmetrical bilateral skeletal traits than their flock mates. Contrary to our prediction, victims of cannibalistic attacks to the head/neck area (N=23) tended to have larger combs than their flock mates (Wilcoxon matched-pairs signed-ranks test, S=59, P=0.037, NS after sequential Bonferroni adjustment). Their cannibals were more asymmetrical than non-cannibalistic bystanders (metatarsus length, S=48, P=0.011 and composite asymmetry, S=62.5, P=0.002, significant after sequential Bonferroni adjustment). In agreement with our prediction, victims of cannibalistic attacks to other body parts (N=27), including the back, wings, rump, tail, cloaca, abdomen and toes, were more asymmetrical (composite asymmetry, S=78, P=0.022, significant after sequential Bonferroni adjustment) and tended to have lower body weights (S=79.5, P=0.029, NS after sequential Bonferroni adjustment) than their flock mates. Their cannibals did not differ in skeletal or ornamental traits from the non-participating bystanders. The results suggest that large combs either elicit attacks to the head and neck area or increase vulnerability to injury during such attacks. Attacks to other body parts appear to be directed towards birds with signs of weakness relative to their flock mates. In these attacks, there were no distinguishing features separating cannibals from bystanders, suggesting that the bystanders could all be potential cannibals.
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Notes Approved no
Call Number Serial 2092
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Author Krueger, K.; Schwarz, S.; Marr, I.; Farmer, K.
Title Laterality in Horse Training: Psychological and Physical Balance and Coordination and Strength Rather Than Straightness Type Magazine Article
Year 2022 Publication (down) Animals Abbreviated Journal Animals
Volume 12 Issue 8 Pages 1042
Keywords balance; body asymmetry; equitation; horse; motor laterality; sensory laterality; stress; welfare
Abstract For centuries, a goal of training in many equestrian disciplines has been to straighten the horse, which is considered a key element in achieving its responsiveness and suppleness. However, laterality is a naturally occurring phenomenon in horses and encompasses body asymmetry, motor laterality and sensory laterality. Furthermore, forcibly counterbalancing motor laterality has been considered a cause of psychological imbalance in humans. Perhaps asymmetry and laterality should rather be accepted, with a focus on training psychological and physical balance, coordination and equal strength on both sides instead of enforcing “straightness”. To explore this, we conducted a review of the literature on the function and causes of motor and sensory laterality in horses, especially in horses when trained on the ground or under a rider. The literature reveals that body asymmetry is innate but does not prevent the horse from performing at a high level under a rider. Motor laterality is equally distributed in feral horses, while in domestic horses, age, breed, training and carrying a rider may cause left leg preferences. Most horses initially observe novel persons and potentially threatening objects or situations with their left sensory organs. Pronounced preferences for the use of left sensory organs or limbs indicate that the horse is experiencing increased emotionality or stress, and long-term insufficiencies in welfare, housing or training may result in left shifts in motor and sensory laterality and pessimistic mentalities. Therefore, increasing laterality can be regarded as an indicator for insufficiencies in housing, handling and training. We propose that laterality be recognized as a welfare indicator and that straightening the horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title Animals
Series Volume 12 Series Issue 8 Edition
ISSN 2076-2615 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 6670
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Author Austin, N.P.; Rogers, L.J.
Title Limb preferences and lateralization of aggression, reactivity and vigilance in feral horses, Equus caballus Type Journal Article
Year 2012 Publication (down) Animal Behaviour Abbreviated Journal Anim. Behav.
Volume 83 Issue 1 Pages 239-247
Keywords aggression; behavioural asymmetry; Equus caballus; eye preference; feral horse; limb preference; reactivity; side bias
Abstract Observational field studies were conducted on two remote populations of feral horses in Australia to determine whether lateralization is a characteristic of Equus caballus as a species or results from handling by humans. Group 1 had been feral for two to five generations and Group 2 for 10–20 generations. In both groups, left-side biases were present during agonistic interactions and in reactivity and vigilance. Therefore, as in other vertebrates, the right hemisphere appears to be specialized to control agonistic behaviour and responses to potential threats. The leftwards bias was stronger in measures of behaviour involving more aggression and reactivity. Preferences to place one forelimb in front of the other during grazing were also determined. No population bias of forelimb preference was found, suggesting that such limb preferences present in domestic horses may be entrained. Since stronger individual limb preferences were found in immature than in adult feral horses, limb preference may be modified by maturation or experience in the natural habitat. Stronger limb preference was associated significantly with elevated attention to the environment but only in younger feral horses. No sex differences in lateralization were found. The findings are evidence that horses show visual lateralization, as in other vertebrates, not dependent on handling by humans. Limb preference during grazing, by contrast, does appear to depend on experience.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN 0003-3472 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5651
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