Animal Behaviour

RÉSUMÉ : Nous nous pencherons sur les travaux du jeune Heidegger afin de montrer que, s’il affirme dans Être et temps que les animaux ne sont ni chose, ni Dasein, mais participent d’un énigmatique mode d’être propre – le « simplement vivant », ce qui ne fait « rien de plus que vivre » – cela constitue un revirement dans la pensée heideggérienne. Dans les travaux qui préparent la rédaction de Sein und Zeit, l'animal avait toujours été considéré comme un être qui a un monde, comme un être auquel nous devons reconnaître le mode d'être du Dasein. En s’appuyant sur l’interprétation phénoménologique d’Aristote qu’il présente dans ses cours de 1919 à 1926, nous montrerons que les structures fondamentales de l'être-au-monde ont été élaborées sur le fond des capacités propres à la vie animale que sont l’affection (pathos), la perception (aisthēsis), la discrimination (krinein), la mobilité (kinesis kata topon) et le désir (orexis).

ABSTRACT : Our investigation of young Heidegger’s work aims at showing that, if Being and Time states that animals are neither mere things, neither Dasein, but have their own puzzling mode of being – “mere life”, which does not exist, but simply lives – this constitutes a reversal in Heidegger’s way of thinking. In the works that prepared the way towards Sein und Zeit, animal life was always presented as being-in-a-world, as a being to which we must ascribe Dasein’s way of being. With the help of Heidegger’s phenomenological interpretations of Aristotle presented between 1919 and 1926, we will show that the basic features of being-in-the-world that will become Being and Time's existential structures were developed on the basis of capacities belonging to animal life : affection (pathos), perception (aisthēsis), discrimination (krinein), mobility (kinesis kata topon) and desire (orexis).

To behave in an adaptive way an animal must refer to information. Consider what happens when a motorist comes to traffic lights at red. The motorist usually stops. Stopping avoids the high risk of damage and injury at the cost of one or two minutes. So stopping at red traffic lights is the best way for the motorist to behave.

Recently, there has been much interest in the role of endogenous and maternal hormones as regulators of offspring begging and mediators of parent–offspring conflict. Here, we review recent work in this field, and identify inconsistencies in the literature. We find good evidence that hormones play a role as regulators of begging: 13 studies report a positive effect on begging and six a negative effect. There is also good evidence that hormones influence offspring fitness, but the direction of reported effects is inconsistent: eight studies report a positive effect on offspring fitness and 10 a negative effect. We explore potential pathways linking hormonal effects on begging and growth. We find that our current understanding of these pathways is incomplete, and suggest a simple model linking hormonal effects on begging and growth. We next discuss the role of hormones as mediators of parent–offspring conflict. We find little evidence that maternal hormones provide a mechanism for parental favouritism. We use graphical models to explore the hypothesis that maternal hormones act as honest signals, and find that costs of hormone production can ensure the honesty of maternal hormones but only under very restricted conditions. We discuss evidence from recent cross-fostering experiments suggesting that maternal hormones act in the context of overlapping interests between parents and offspring. Finally, we highlight the need for more studies on nonavian taxa to establish whether hormonal regulation of begging is specific to birds or general across taxa where offspring beg for food from their parents.

- After the exceptional influx of Booted eagles Hieraaetus pennatus from Western Europe in October 2004, we reviewed thespecies’ presence in Italy over the period December 2004 - February 2005 and during spring 2005. We documented the size of the spe-cies’ wintering population by gathering the sightings from various regions of Italy. We surveyed the spring migration of the speciesthrough simultaneous raptor counts at several sites (mostly in Sicily and Sicilian islands). The remarkable wintering population of 2004-2005 (estimated range: 173 - 202 individuals) was related to the unusual migratory influx that took place in the previous autumn and itagrees with an apparent trend towards an increasing number of birds wintering in southern Italy, particularly in Sicily (estimated range :132 – 157 individuals). The northward spring migration observed from the southern regions of Italy along the Tyrrhenian coast (towardsFrance), validates the hypothesis of a West European origin of the ind...

... In this way reciprocity can occur whether or not individuals differ in their general tendency to direct acts. ... Individual variation in social inter-action frequencies is realistic. For instance, wild malechimpanzees each havetheir own character-istic grooming duration (Simpson ...

Comparative studies of vocal repertoires over the geographical range of a species can improve our understanding of the function and evolution of animal vocalizations. They may also help to elucidate relationships between populations, where genetic studies are missing or ...

Aerobic organisms naturally create reactive oxygen species (ROS) as by-products of energy production. These substances can damage DNA and tissue, and probably are major causes of mutation, ageing and a host of diseases. Oxidative stress occurs when an organism produces an overabundance of ROS relative to ROS-neutralizing antioxidants. In this study, we examined the hypotheses that individual differences in oxidative stress are associated with fluctuating asymmetry and with perceived mate quality. We measured urinary biomarkers of oxidative stress (8-hydroxy-2′-deoxyguanosine (8-OHdG) and malondialdehyde (MDA)) in a sample of healthy, young men and tested their association with fluctuating asymmetry and physical attractiveness. A composite measure of oxidative stress correlated positively with FA and negatively with physical attractiveness (with exposure to toxins, smoking, and their interaction statistically controlled for). Follow-up analyses yielded associations of oxidative stress with both healthy and masculine appearance. No association was mediated by cortisol or testosterone. These findings may yield insights into previously unidentified factors that affect the development of phenotypic features under sexual selection and contribute to the shape of human life histories, and have potential implications for other species as well.

Co-orientation with others by using their gaze direction is considered to be adaptive for detecting food or predators or monitoring social interactions. Like the great apes, common ravens are capable of following human experimenters' gaze direction not only into distant space but also behind visual barriers. We investigated the ontogenetic development of these abilities by confronting birds with a human foster parent looking up (experiment 1) and behind visual barriers (experiment 3) and their modification by habituation (experiments 2 and 4). We tested a group of 12 hand-reared ravens during their first 10 months of life. Ravens responded to others' look-ups soon after fledging but could track their gaze behind a visual barrier only 4 months later, at the age they usually become independent from their parents. Furthermore, ravens quickly ceased responding to repeated look-ups by the model, but did not habituate to repeated gaze cues directed behind a barrier. Our findings support the idea that the two modes of gaze following reflect different cognitive levels in ravens and, possibly, have different functions.