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Author |
Franceschini, C.; Siutz, C.; Palme, R.; Millesi, E. |
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Title |
Seasonal changes in cortisol and progesterone secretion in Common hamsters |
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Journal Article |
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Year  |
2007 |
Publication |
General and Comparative Endocrinology |
Abbreviated Journal |
Gen Comp Endocrinol |
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Volume |
152 |
Issue |
1 |
Pages |
14-21 |
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Keywords |
Animals; Cortisone/*secretion; Cricetinae/*metabolism; Feces/chemistry; Female; Lactation/physiology; Male; Pregnancy; Progesterone/*secretion; Reproduction/physiology; *Seasons; Sexual Behavior, Animal/physiology |
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Abstract |
In this study, we investigated endocrine factors and behaviour in free-living Common hamsters (Cricetus cricetus) during reproductive and non-reproductive periods of the annual cycle. We applied a non-invasive method to gain information on seasonal changes in adrenocortical activity in male and female hamsters by analysing faecal glucocorticoid metabolite concentrations (FCM). In addition, plasma progesterone concentrations were monitored in females throughout the non-hibernation season. The animals were live-trapped from spring emergence until the onset of hibernation in autumn. Reproductive status was determined at capture and blood and faecal samples were collected. During behavioural observations, agonistic and sexual interactions were recorded. FCM concentrations were significantly higher in males than in females during the reproductive period. In males, a pronounced increase in FCM during the reproductive period coincided with high frequencies of intrasexual aggression. In females, FCM levels remained relatively constant. Aggressive behaviour in females increased during the reproductive period, but was much less frequent than in males. Females, which successfully raised a second litter after a postpartum oestrus and concurrent lactation and gestation had lower FCM levels than individuals, which lost their second litter after parturition. As expected, plasma progesterone concentrations were low before and after the reproductive period. During gestation, levels peaked and remained elevated during lactation. The results of this field study provide insight in critical periods associated with reproduction in male and female Common hamsters. |
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Address |
Department of Behavioural Biology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria. claudia.franceschini@univie.ac.ct |
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0016-6480 |
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PMID:17408667 |
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Call Number |
Equine Behaviour @ team @ |
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4076 |
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Author |
De Boyer Des Roches, A.; Richard-Yris, M.-A.; Henry, S.; Ezzaouia, M.; Hausberger, M. |
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Title |
Laterality and emotions: visual laterality in the domestic horse (Equus caballus) differs with objects' emotional value |
Type |
Journal Article |
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Year |
2008 |
Publication |
Physiology & Behavior |
Abbreviated Journal |
Physiol. Behav. |
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Volume |
94 |
Issue |
3 |
Pages |
487-490 |
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Keywords |
Animals; Animals, Newborn; Behavior, Animal/physiology; Dominance, Ocular/*physiology; *Emotions; Exploratory Behavior/physiology; Female; Horses/*physiology; Olfactory Pathways/physiology; Pattern Recognition, Visual/*physiology; Photic Stimulation; Pregnancy; Statistics, Nonparametric; Visual Fields/physiology |
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Abstract |
Lateralization of emotions has received great attention in the last decades, both in humans and animals, but little interest has been given to side bias in perceptual processing. Here, we investigated the influence of the emotional valence of stimuli on visual and olfactory explorations by horses, a large mammalian species with two large monocular visual fields and almost complete decussation of optic fibres. We confronted 38 Arab mares to three objects with either a positive, negative or neutral emotional valence (novel object). The results revealed a gradient of exploration of the 3 objects according to their emotional value and a clear asymmetry in visual exploration. When exploring the novel object, mares used preferentially their right eyes, while they showed a slight tendency to use their left eyes for the negative object. No asymmetry was evidenced for the object with the positive valence. A trend for an asymmetry in olfactory investigation was also observed. Our data confirm the role of the left hemisphere in assessing novelty in horses like in many vertebrate species and the possible role of the right hemisphere in processing negative emotional responses. Our findings also suggest the importance of both hemispheres in the processing positive emotions. This study is, to our knowledge, the first to demonstrate clearly that the emotional valence of a stimulus induces a specific visual lateralization pattern. |
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Address |
UMR CNRS 6552 Ethologie-Evolution-Ecologie, Universite de Rennes 1, Avenue du General Leclerc, Campus de Beaulieu, F-35042 Rennes Cedex, France. a.de-boyer@wanadoo.fr |
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0031-9384 |
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PMID:18455205 |
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Call Number |
Equine Behaviour @ team @ |
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4762 |
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