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Godin, J. - G. J., Herdman, E. J. E., & Dugatkin, L. A. (2005). Social influences on female mate choice in the guppy, Poecilia reticulata: generalized and repeatable trait-copying behaviour. Anim. Behav., 69(4), 999–1005.
Abstract: In vertebrates, the mating preferences of individual females can be flexible and the probability of a female mating with a particular male can be significantly increased by her having previously observed another conspecific female affiliate and mate with that same male. In theory, such mate-choice-copying behaviour has potentially important consequences for both the genetic and social (`cultural') transmission of female mating preferences. For copying to result in the `cultural inheritance' of mating preferences, individual females must not only copy the mate choice decisions of other females but they also should tend to repeat this type of behaviour (i.e. make similar mating decisions) subsequently and to generalize their socially induced preference for a particular male to other males that share his distinctive characteristics. Here, we show experimentally that individual female guppies, Poecilia reticulata, not only copy the observed mating preferences of other females for particular males, but that the preference now assumed via copying is subsequently repeated and generalized to other males of a similar colour phenotype. These results provide empirical evidence for social enhancement of female preference for particular phenotypic traits of chosen males rather than for the particular males possessing those traits, and thus have important implications for our understanding of the role of social learning in the evolution of female mating preferences and of male epigamic traits.
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Hare, J. F. (2005). Lee Alan Dugatkin, Principles of Animal Behavior, Norton, New York (2004) Pp. xx+596. Price $80.00. Anim. Behav., 69(1), 247–248.
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Feh, C. (2005). Relationships and Communication in Socially Natural Horse Herds. In D. S. Mills, & S. M. McDonnell (Eds.), The domestic horse : the origins, development, and management of its behaviour. Cambridge: Cambridge University Press 2005.
Abstract: Horses are quite unique. In most mammals, sexes segregate and maintain bonds only during the breeding season (Clutton-Brock, 1989). Some canids, a few rodents and primate species such as gorillas, hamadryas baboons and red howler monkeys are the exception, where the same males stay with the same females all year round and over many breeding seasons. Typically, both sexes disperse at puberty in these species. In horses, it was clearly shown that the causes for female dispersal were incest avoidance and not intra-specific competition (Monard, 1996). As a rule, this is confirmed for mammal species where tenure length by males exceeds the age at first reproduction in females (Clutton-Brock, 1989). When horses are allowed to choose their mating partner freely, the inbreeding coefficient of the offspring is lower than expected should they mate randomly (Duncan et al, 1984).
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Hanggi, E. B. (2005). The Thinking Horse: Cognition and Perception. In International Veterinary Information Service (Vol. 51).
Abstract: Cognition and perception in horses has often been misunderstood. Not only in the past but even today, people proclaim that horses react only by instinct, that they are just conditioned-response animals, that they lack advanced cognitive ability, and that they have poor visual capabilities (e.g., acuity, color vision, depth perception). Until relatively recently, there was little scientific evidence to address such beliefs. Change, however, is underway as scientific and public interest in all aspects of equine learning and perception intensifies. A review of the scientific literature, as well as practical experience, shows that horses excel at simpler forms of learning such as classical and operant conditioning, which is not surprising considering their trainability when these principles and practices are applied. Furthermore, horses have shown ease in stimulus generalization and discrimination learning. Most recently and unexpected by many, horses have solved advanced cognitive challenges involving categorization learning and some degree of concept formation. A comprehensive understanding of the cognitive and perceptual abilities of horses is necessary to ensure that this species receives proper training, handling, management, and care.
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Adams, E. S. (2005). Bayesian analysis of linear dominance hierarchies. Anim. Behav., 69(5), 1191–1201.
Abstract: Studies on social animals often seek to identify dominance hierarchies, in which individuals are ranked according to competitive abilities based on counts of wins and losses in pairwise encounters. I illustrate Bayesian approaches, based on the method of paired comparisons, for determining ranks and for estimating relationships between dominance ability and other attributes. Bayesian inference combines prior probability distributions for each unknown parameter with likelihood functions to produce the joint posterior probability distribution for the quantities of interest. In contrast to nonparametric techniques for inferring ranks, Bayesian models yield measures of certainty for each inference and allow rigorous estimates of correlations between ranks and covariates even when there is considerable uncertainty as to the ranks themselves. A possible objection to the Bayesian approach is that it appears to entail more restrictive assumptions than do simpler methods. However, simulations show that Bayesian inferences are more robust to deviations from these assumptions than are the results of nonparametric methods.
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Hemelrijk, C. K., Wantia, J., & Gygax, L. (2005). The construction of dominance order: comparing performance of five methods using an individual-based model. Behaviour, 142(8), 1043–1064.
Abstract: In studies of animal behaviour investigators correlate dominance with all kinds of behavioural
variables, such as reproductive success and foraging success. Many methods are used to
produce a dominance hierarchy from a matrix reflecting the frequency of winning dominance
interactions. These different methods produce different hierarchies. However, it is difficult to
decide which ranking method is best. In this paper, we offer a new procedure for this decision:
we use an individual-based model, called DomWorld, as a test-environment. We choose this
model, because it provides access to both the internal dominance values of artificial agents
(which reflects their fighting power) and the matrix of winning and losing among them and,
in addition, because its behavioural rules are biologically inspired and its group-level patterns
resemble those of real primates. We compare statistically the dominance hierarchy based on
the internal dominance values of the artificial agents with the dominance hierarchy produced
by ranking individuals by (a) their total frequency of winning, (b) their average dominance
index, (c) a refined dominance index, the David`s score, (d) the number of subordinates each
individual has and (e) a ranking method based on maximizing the linear order of the hierarchy.
Because dominance hierarchies may differ depending on group size, type of society, and the
interval of study, we compare these ranking methods for these conditions.We study complete
samples as well as samples randomly chosen to resemble the limitations of observing real
animals. It appears that two methods of medium complexity (the average dominance index
and David`s score) lead to hierarchical orders that come closest to the hierarchy based on
internal dominance values of the agents. We advocate usage of the average dominance index,
because of its computational simplicity.
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Hemelrijk, C. K., & Wantia, J. (2005). Individual variation by self-organisation. Neurosci Biobehav Rev, 29(1), 125–136.
Abstract: In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.
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Huebener, E. (2005). Listening to Nature: Ways to A Balanced Seat and Understanding the Correct Timing for the Rider's Aids. Tierärztl. Umschau, 2, 90–99.
Abstract: In the publication “Movements of trunk and back of the horse from a riders view” in the TU 59, 327-334, 2004 the author suggested that academic research is necessary to determine measurable parameters for these agents of the horse's movement.
The discovery of the importance of the trunk-back-movements for a sensitive and horse-oriented riding style is closely connected to the development of the balanced seat and the technique of receiving signals from and sending signals to the horse at the right time (riders would say: “the feel and the impact”). The history of this interaction between horse and rider can be traced for four and a half centuries. A short digest will be published here later. Again the studies result in a demand for interdisciplinary academic research.
There is an urgent need to clarify the impact of the riders's seat and aids (two more pillars in the art of riding) in the interest teaching riding correctly and more efficiently at the so-called 'basis' of our sport.
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Huebener, E. (2005). Solving the Riddle of the Rider's Seat (Working title: Making the Rider Really “Sit”). Mecl. Pferde J., 3.
Abstract: The movements of the horse's back and trunk can be deducted from the foot sequences of the horse's basic paces. This knowledge builds a solid foundation in the schooling of the rider's seat. The decisive aspects of these movements are described here.
Some basics (mostly well-known) in the schooling of the rider's seat are graded here. More recent findings from observing the horse's back and trunk movements and their consequence for the rider's seat can easily be explained in three points. These points will be enhanced by graphic explanations of the principle as a whole
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Huebener, E. (2005). Rider's Aids for Transitions Between Different Gaits ? The Movements of the Horse's Trunk and Back as Timers for the Rider's Influence. Trakehner Hefte, 5-11.
Abstract: Abstract
According to Ludwig Koch, the horse's transition from one gait to another is only possible during a particular phase in its' movement cycle (respectively in a half of it's movement cycle) in one gait to a particular phase in its' movement cycle (respectively in a half of it's movement cycle) in the other gait.
It only takes a fraction of a second for these movements to occur. It is precisely in these moments that according to the European classical riding school principles the rider has to give the appropriate aids, because only then the horse can execute them in a flash. In order to give the aids in the “fitting” moment, the rider needs a timer. The only available and reliable indicators of the right timing are the movements of the horse's trunk and back.
The connections between the different phases of the movements during the basic gaits, the rider's seat which follows all the movements of the horse's back with a freely rotating pelvis, and the rider's leg which – from step to step, from footfall to footfall, from canter beat to canter beat – wants to follow the horse's swinging trunk (until it is finally – controlled by the rider – free to do so, at the right moment), are being shown for the first time in easy to follow miniature picture sequences.
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