|
Drummond, H. (2006). Dominance in vertebrate broods and litters. Quarterly Review of Biology, 81(1), 3–32.
Abstract: Drawing on the concepts and theory of dominance in adult vertebrates, this article categorizes the relationships of dominance between infant siblings, identifies the behavioral mechanisms that give rise to those relationships, and proposes a model to explain their evolution. Dominance relationships in avian broods can be classified according to the agonistic roles of dominants and subordinates as “aggression-submission,” “aggression-resistance, ” “aggression-aggression,” “aggression-avoidance,” “rotating dominance,” and “flock dominance.” These relationships differ mainly in the submissiveness/pugnacity of subordinates, which is pivotal, and in the specificity/generality of the learning processes that underlie them. As in the dominance hierarchies of adult vertebrates, agonistic roles are engendered and maintained by several mechanisms, including differential fighting ability, assessment, trained winning and losing (especially in altricial species), learned individual relationships (especially in precocial species), site-specific learning, and probably group-level effects. An evolutionary framework in which the species-typical dominance relationship is determined by feeding mode, confinement, cost of subordination, and capacity for individual recognition, can be extended to mammalian litters and account for the aggression-submission and aggression-resistance observed in distinct populations of spotted hyenas and the “site-specific dominance” (teat ownership) of some pigs, felids, and hyraxes. Little is known about agonism in the litters of other mammals or broods of poikilotherms, but some species of fish and crocodilians have the potential for dominance among broodmates. Copyright © 2006 by The University of Chicago. All rights reserved.
|
|
|
Ligout, S., & Porter, R. - H. (2006). Social recognition in mammals: Mechanisms and sensorial bases. Prod. Anim., 19(2), 119–133.
Abstract: Social recognition plays a major role in the mediation of interactions between individuals and the organisation of societies. During the last 20 years, numerous studies have investigated the adaptive significance, underlying mechanisms and sensory basis of individual recognition of kin as well as non-kin. The results indicate that the recognition of conspecifics involves complex, flexible processes that are widespread throughout the vertebrate kingdom. Such recognition can be based upon different mechanisms and sensory modalities, and influenced by diverse factors. Learned phenotypic traits of conspecifics through familiarisation, including oneself, is the fundamental mechanism implicated in recognition. Animals become directly familiar with others with which they interact. Moreover, kin of familiar conspecifics may be discriminated because of their resemblance to the known individuals. An animal's genotype and environmental variables may both contribute to its recognisable individual signatures (e.g. distinctive olfactory, visual, or auditory characteristics). In general, the study of social recognition enhances our understanding of the cognitive world of animals.
|
|
|
Ferrari, M. C. O., Capitania-Kwok, T., & Chivers, D. P. (2006). The role of learning in the acquisition of threat-sensitive responses to predator odours. Behav. Ecol. Sociobiol., 60(4), 522–527.
Abstract: The supposition that prey animals respond to a predator with an intensity that matches the risk posed by the predator is known as the threat-sensitive predator avoidance hypothesis. Many studies have provided support for this hypothesis; yet, few studies have attempted to determine how such abilities are acquired by prey species. In this study, we investigated whether fathead minnows (Pimephales promelas) could learn to recognize an unknown predator (northern pike, Esox lucius) in such a way that they could match the intensity of their antipredator response with the threat posed by the predator. We exposed pike-naive minnows to conspecific alarm cues paired with either a high or low concentration of pike odor. The following day, both groups were tested for a response to either high or low concentration of pike odor alone. We found that minnows conditioned with alarm cues paired with a given concentration of pike odor subsequently responded with a higher intensity to higher concentrations of pike odor, and with a lower intensity to lower concentrations of pike odor. These results demonstrate that during a single conditioning trial, minnows learn the identity of the predator in a threat-sensitive manner. Minnows use predator odor concentrations that they experience in subsequent interactions to adjust the intensity of their antipredator behavior. © Springer-Verlag 2006.
|
|
|
Grinder, M. I., Krausman, P. R., & Hoffmann, R. S. (2006). Equus asinus. Mammalian Species, 794(1), 1–9.
|
|
|
Pell, M. D. (2006). Cerebral mechanisms for understanding emotional prosody in speech. Brain and Language, 96(2), 221–234.
Abstract: Hemispheric contributions to the processing of emotional speech prosody were investigated by comparing adults with a focal lesion involving the right (n = 9) or left (n = 11) hemisphere and adults without brain damage (n = 12). Participants listened to semantically anomalous utterances in three conditions (discrimination, identification, and rating) which assessed their recognition of five prosodic emotions under the influence of different task- and response-selection demands. Findings revealed that right- and left-hemispheric lesions were associated with impaired comprehension of prosody, although possibly for distinct reasons: right-hemisphere compromise produced a more pervasive insensitivity to emotive features of prosodic stimuli, whereas left-hemisphere damage yielded greater difficulties interpreting prosodic representations as a code embedded with language content.
|
|
|
Sato, W., & Aoki, S. (2006). Right hemispheric dominance in processing of unconscious negative emotion. Brain and Cognition, 62(3), 261–266.
Abstract: Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.
|
|
|
Trillmich, F., & Rehling, A. (2006). Animal Communication: Parent-Offspring. In Keith Brown (Ed.), Encyclopedia of Language & Linguistics (pp. 284–288). Oxford: Elsevier.
Abstract: Parent-offspring communication has evolved under strong selection to guarantee that the valuable resource of parental care is expended efficiently on raising offspring. To ensure allocation of parental care to their own offspring, individual recognition becomes established in higher vertebrates when the young become mobile at a time when a nest site can no longer provide a safe cue to recognition. Such recognition needs to be established by rapid, sometimes imprinting-like, processes in animals producing precocial offspring. In parents, offering strategies that stimulate feeding and entice offspring to approach the right site have evolved. Such parental signals can be olfactory, acoustic, or visual. In offspring, begging strategies involve shuffling for the best place to obtain food – be this the most productive teat or the best position in the nest. This involves signals that make the offspring particularly obvious to the parent. Parents often feed young according to their signaling intensity but may also show favoritism for weaker offspring. Offspring signals also serve to communicate the continuing presence of the young and may thereby maintain brood-care behavior in parents. Internal processes in parents may end parental care irrespective of further signaling by offspring, thus ensuring that offspring cannot manipulate parents into providing substantially more care than is optimal for their own fitness.
|
|
|
Holekamp, K. E. (2006). Questioning the social intelligence hypothesis. Trends. Cognit. Sci., 11(2), 65–69.
Abstract: The social intelligence hypothesis posits that complex cognition and enlarged [`]executive brains' evolved in response to challenges that are associated with social complexity. This hypothesis has been well supported, but some recent data are inconsistent with its predictions. It is becoming increasingly clear that multiple selective agents, and non-selective constraints, must have acted to shape cognitive abilities in humans and other animals. The task now is to develop a larger theoretical framework that takes into account both inter-specific differences and similarities in cognition. This new framework should facilitate consideration of how selection pressures that are associated with sociality interact with those that are imposed by non-social forms of environmental complexity, and how both types of functional demands interact with phylogenetic and developmental constraints.
|
|
|
Chaya, L., Cowan, E., & McGuire, B. (2006). A note on the relationship between time spent in turnout and behaviour during turnout in horses (Equus caballus). Appl. Anim. Behav. Sci., 98(1-2), 155–160.
Abstract: We examined if time spent in turnout influenced behaviour during turnout for horses maintained in stalls and given either 2 h/week (n = 7) or 12 h/week (n = 7) of turnout. Horses turned out for 2 h/week were more likely than those turned out for 12 h/week to trot, canter, and buck. Frequency of trotting and cantering was also higher and frequency of grazing lower in horses turned out for 2 h/week. These results have welfare implications and support previous studies showing that horses react to confinement with increased activity when not confined.
|
|
|
Schiele, K. A. L. M. (2006). Einfluss reduzierter Futterzuteilung zweier verschiedener Heuqualitäten auf Passagedauer und Verdaulichkeit bei Ponies. Doctoral thesis, , .
Abstract: Über die Auswirkungen der Futtermenge und der Futterqualität auf die scheinbare
Verdaulichkeit und die mittlere Retentionszeit beim Pferd gibt es zahlreiche Arbeiten
mit zum Teil recht widersprüchlichen Ergebnissen. So existiert eine Hypothese,
wonach bei geringerer Energiedichte im Futter die TS-Aufnahme steigt und die
mittlere Retentionszeit abnimmt. Dadurch soll bei Equiden eine ausreichende
Energieaufnahme trotz geringer Energiedichte im Futter erreicht werden (JANIS
1976, DUNCAN et al.1990). In nahezu allen Studien zu diesem Thema wurden Futter
mit unterschiedlichem Nährstoffgehalt bei konstanter Futteraufnahme bzw. ad libitum
Fütterung untersucht. Nur bei PEARSON et al. (2001 und 2006) findet sich für jedes
Futter ein Vergleich von zwei verschiedenen Futtermengen, nämlich ad libitum und
70% der ad libitum Futteraufnahme. Systematische Untersuchungen bei Pferden zu
Futtermengen, die unterhalb des Erhaltungsbedarfes liegen, fehlen bisher.
In der vorliegenden Arbeit sollen deshalb im Wesentlichen drei Fragen geklärt
werden:
· Gibt es einen Einfluss von Futtermengen unterhalb des Erhaltungsbedarfes auf
die mittlere Retentionszeit?
· Haben Veränderungen der mittleren Retentionszeit einen Einfluss auf die
scheinbare Verdaulichkeit?
· Wie unterscheiden sich diese Effekte in Abhängigkeit von der
Futterzusammensetzung?
Die Ergebnisse dieser Studie sollen vor allem bezüglich ihrer Auswirkungen auf die
praktische Pferdefütterung betrachtet werden.
|
|