Abstract: Intraspecific allometric calculations of the brain to body size relation revealed distinct differences between 127 (67; 60) ancestral wild cavies and 82 (37; 45) guinea pigs, their domesticated relatives. The dependency of both measures from one another remained the same in both animal groups but the brains of guinea pigs were by 14.22% smaller at any net body weight. Consistent with results in other species the domestication of Cavia aperea is also characterized by a decrease of brain size. Fresh tissue sizes of the five brain parts medulla oblongata, cerebellum, mesencephalon, diencephalon and telencephalon were determined for 6 cavies and 6 guinea pigs by the serial section method. Additionally the sizes of 16 endbrain structures and those of the optic tract, the lateral geniculate body and the cochlear nucleus were measured. Different decrease values resulted for all these structures concomitant with domestication as was calculated from the amount of total brain size decrease and average relative structure values in the wild as well as the domesticated brain. The size decrease of the entire telencephalon (-13.7%) was within the range of the mean overall reduction as similarly was the case for the total neocortex (-10.7%) whereas the total allocortex (-20.9%) clearly was more strongly affected. The size decrease of the olfactory bulb (-41.9%) was extreme and clearly higher than found for the secondary olfactory structures (around -11%). The primary nuclei of other sensory systems (vision, audition) were decreased to less extent (lateral geniculate: -18.1%; cochlear nucleus: -12.6%). Mass decreases of pure white matter parts were nearly twice as high in contrast to associated grey matter parts (neocortex white versus grey matter; tractus opticus versus lateral geniculate body). The relatively great decrease values found for the limbic structures hippocampus (-26.9%) and schizocortex (-25.9%) are especially notable since they are in good conformity with domestication effects in other mammalian species. The findings of this study are discussed with regard to results of similar investigations on wild and domesticated gerbils (Meriones unguiculatus), the encephalization of the wild form, the special and species-specific mode and duration of domestication and in connection with certain behavioral changes as resulted from comparative investigations in ethology, socio-biology, endocrinology and general physiology.

Abstract: Animals use communicative signals, such as gesture or gaze, to communicate to someone the intention or expression of the sender, which is called social cue. In the previous studies, it was suggested the skill of reading human social cue in domestic animals are influenced to the domestication, the experience contacting with human and training to obey human. In this present study, we tested the skill for horses (Equus caballus) kept in year-round grazing conditions using 33 horses differed from breed and the degree of the experience with human by object-choice task subjects choosing either of bait boxes located at the end of experimenter. As results, non-socialized horses hardly responded to human social cues. Habituated horses that were both of trained and untrained responded to human social cues, but their accuracy rates were not more than 50% except for two trained subjects. For the skill of reading human social cues, there was high individual variation in responding to human social cues in horses kept in year-round grazing conditions. The individual characteristics influenced to it more than domestication, the experience with human, and training to obey human.

Abstract: Contrary to the widely-spread assumption that horses just have restricted cognitive capacities and are not very flexible in their behaviors, we showed that horses display innovative behavior and even make use of tools (Krueger 2015, Krueger et al. 2015). These findings derive from a database (http://innovative-behaviour.org/) the Equine behavior team managed in the past two years. Some horses did not only show single innovations, but several different innovations. The number of innovations per individual varied from 1 to 10. 20 % of all innovative horses in the database showed more than one innovation. These individuals can be called the ‘true innovators’. Moreover innovations were dependent on age. Young horses were more innovative than older ones, whereby horses at the age of five to nine years were the most innovative. When considering the housing system innovative horses in a single housing (inside box, outside box, paddock box) had a slight majority towards horses in group housing (open stable, active stable, pasture day and night). But given the fact that ratings on housing system frequencies state 95% of the horses to be kept in individual housing, innovations in individual housing are rare. Nevertheless, horses kept in inside boxes without a window, opened doors more often than all other horses. Aside from this effect, housing systems did not trigger the frequency of innovative behavior. Innovations for gaining freedom and innovations in general were widespread among horses with daily access to pasture and daily contact with conspecifics. Innovations for gaining food were not more likely to occur in horses that were fed little amounts of roughage. In conclusion, the housing of horses does not seem to be the primary catalyst for developing innovative behavior in horses. What makes a “true innovator” in horses, in addition to age, remains to be seen.

Abstract: Primate sociality has received much attention and its complexity has been viewed as a driving force for the evolution of cognitive abilities. Improved analytic techniques have allowed primate researchers to reveal intricate social networks based on the exchange of cooperative acts and services. Although nonprimates are known to show similar behavior (e.g., cooperative hunting, food sharing, coalitions) there seems a consensus that social life is less complex than in primates. Here the authors present the first group-level analysis of reciprocity of social interactions in a social carnivore, the ring-tailed coati (<xh:i xmlns:search=“http://marklogic.com/appservices/search” xmlns=“http://apa.org/pimain” xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance” xmlns:xh=“http://www.w3.org/1999/xhtml”>Nasua nasua</xh:i>). The authors found that support in aggressive conflicts is a common feature in coatis and that this behavior is reciprocally exchanged in a manner seemingly as complex as in primates. Given that reciprocity correlations persisted after controlling for the effect of spatial association and subunit membership, some level of scorekeeping may be involved. Further studies will be needed to confirm our findings and understand the mechanisms underlying such reciprocity, but our results contribute to the body of work that has begun to challenge primate supremacy in social complexity and cognition. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Abstract: The purpose of this study is to find convincing arguments, how horses should be ridden correctly, especially concerning the best head and neck position. Currently in the riding world, the opinions differ: The traditional way is to ride a horse with its nose in front of the vertical, while a new method claims that pulling the nose behind the vertical with an extreme flexion of the poll implies “gymnastic movements”. This article is focussed on the welfare and comfort of the horse in different head-neck positions, expressed by behaviours which document discomfort. As a first step, the behaviour of standing horses was observed while their heads and necks were put into seven postulated or frequently assumed positions. In the hyperflexed position the horses displayed most discomfort (with 49,7% of all reactions, like open mouths, head tossing, tail movements and other signs of resentment). The second strongest reactions of discomfort were shown in the highly raised position of the head (34,9%). The moderately rounded neck position as in traditional dressage lessons was not without signs of discomfort either, but less than the other two positions (11,2%). The high position and the extended position did not cause discomfort at all (0,17% and 0,23% respectively). In a second step, horses moving in all gaits under a rider were observed at competitions without the riders´ knowledge. The total number of observations was divided into two categories (each containing 30 horses) on the basis of the common rules of the FN: ridden with the horse’s nose in front of the vertical and ridden with the horse’s nose behind the vertical. The proportion of horses showing discomfort with the nose behind the vertical was clearly much higher (89,3%) compared to those ridden with the nose in front of the vertical (10,7%). Thus, the horses in the first category displayed signs of discomfort 8 times more frequent than those in the second group. In addition, scans carried out at tournaments showed that 92.8% of the horses were ridden with the nose behind the vertical. A clear result of this study is that the reality of riding differs widely from the rules. These results also show that riding in the hyperflexed position causes a great deal of discomfort for the horses and therefore should be abolished.
Die aktuellen Diskussionen in der Reiterwelt, welche Art und Weise des Reitens, besonders welche Kopf-Hals-Stellung zu erstreben ist, werfen die Frage auf, ob und wie die Pferde selbst ihr Befinden zum Ausdruck bringen. Über die Empfindungen der Pferde in verschiedenen Kopfhaltungen ist bisher sehr wenig bekannt. Deswegen wurde zunächst an stehenden Pferden das Ausdrucksverhalten beobachtet. Missfallensäußerungen häuften sich (mit 49,7% aller gezeigten Verhaltensauffälligkeiten wie Sperren, Rückwärtsgehen und Kopfschlagen) in der aufgerollten, hyperflektierten Stellung des Halses. An zweiter Stelle folgten Unmutsäußerungen in der absolut aufgerichteten Haltung (34,9%). Auch die beigezäumte Haltung wurde nicht ohne Unmutsbekundungen hingenommen, hier war deren Anzahl aber wesentlich geringer (11,2%). Die hohe Kopfstellung (0,17%) und die Dehnungshaltung (0,23%) bereiteten den Tieren kaum Unbehagen. Auch das Ausdrucksverhalten der Pferde unter dem Reiter wurde untersucht. Hierfür wurden, unter Berücksichtigung der schriftlich fixierten Regeln für das Turnierwesen der FN, je 30 Pferde in zwei Kategorien beobachtet: mit der Stirnlinie vor der Senkrechten und Pferde mit der Stirnlinie hinter der Senkrechten. Die Beobachtungen wurden unbemerkt von den Reitern auf den Abreiteplätzen von Turnieren durchgeführt. Die Anzahl an Verhaltensauffälligkeiten der Pferde mit der Stirnlinie hinter der Senkrechten war deutlich (89,3 %) erhöht im Gegensatz zu der anderen Gruppe (10,7 %). Die Pferde mit der Stirnlinie hinter der Senkrechten zeigten 8 Mal mehr Unmutsäußerungen als die mit der Stirnlinie vor der Senkrechten. Entgegen den Regeln der FN zeigten die durchgeführten Scans, dass unmittelbar vor den Prüfungen auf Turnieren 92,8% der Pferde mit der Stirnnasen-Linie hinter der Senkrechten geritten wurden. Ein Befund dieser Studie ist die Feststellung, dass die Praxis deutlich von den Regeln abweicht. Das Reiten mit der Stirnlinie hinter der Senkrechten ist nach diesen Befunden abzulehnen, da die Pferde deutliches Unwohlsein in dieser Haltung signalisieren.