Quantitative abilities in a reptile (Podarcis sicula)

The ability to identify the largest amount of prey available is fundamental for optimizing foraging behaviour in several species. To date, this cognitive skill has been observed in all vertebrate groups except reptiles. In this study we investigated the spontaneous ability of ruin lizards to select the larger amount of food items. In Experiment 1, lizards proved able to select the larger food item when presented with two alternatives differing in size (0.25, 0.50, 0.67 and 0.75 ratio). In Experiment 2 lizards presented with two groups of food items (1 versus 4, 2 versus 4, 2 versus 3 and 3 versus 4 items) were unable to select the larger group in any contrast. The lack of discrimination in the presence ofmultiple items represents an exception in numerical cognition studies, raising the question as to whether reptiles' quantitative abilities are different from those of other vertebrate groups

Pigeon Navigation: Charcoal Filter Removes Relevant Information From Environmental Air

none2---noneH. G. Wallraff; A. FoàH. G., Wallraff; Foa', Augusto Giuseppe Lorenz

The Roles Of Olfaction And Magnetism In Pigeon Homing

none2---noneH. G. Wallraff; A. FoàH. G., Wallraff; Foa', Augusto Giuseppe Lorenz

Variazioni stagionali del ritmo di attività locomotoria nel lacertide Podarcis sicula: un orologio circannuale controllato dalla melatonina?

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The circadian system of reptiles: a multioscillatory and multiphotoreceptive system

Many parameters exhibited by organisms show daily fluctuations that may persist when the organisms are held in constant environmental conditions. Rhythms that persist in constant conditions with a period close to 24 h are called circadian. Although nowadays most research in this field is focused on the molecular and genetic aspectsÐand therefore mostly on two animal models (Drosophila and mouse)Ðthe study of alternative animal models still represent a useful approach to understanding how the vertebrate circadian system is organized, and how this fascinating time-keeping system has changed throughout the evolution of vertebrates. The present paper summarizes the current knowledge of the circadian organization of Reptiles. The circadian organization of reptiles is multioscillatory in nature. The retinas, the pineal, and the parietal eye (and, possibly, the suprachiasmatic nuclei of the hypothalamus, SCN) contain circadian clocks. Of particular interest is the observation that the role these structures play in the circadian organization varies considerably among species and within the same species in different seasons. Another remarkable feature of this class is the redundancy of circadian photoreceptors: retinas of the lateral eyes, pineal, parietal eye, and the brain all contain photoreceptors