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Performance of birds in model cognitive tasks: a cross-taxon comparison
Schlőglová, Nikola ; Exnerová, Alice (advisor) ; Kahounová, Hana (referee)
Bird cognition is an immensely complex topic. Many factors influence how birds acquire, process and act upon obtained information. Some bird groups outshine others regarding their cognitive skills, and the underlying reasons for these differences are extensively researched and discussed. Birds naturally face varying environmental factors that could have driven the evolution of specialised cognitive adaptations not generalisable across all contexts. In contrast, some birds perform well in a broad range of cognitive tasks and may possess general intelligence. Model cognitive tasks help us gain standardised data on birds' cognitive performances to compare them across different taxa, which enables us to identify potential parallels. This thesis covers selected model cognitive tasks: string-pulling tasks, reasoning by exclusion tasks, transitive inference tasks, tasks related to mirror use and reversal learning tasks, for which it analyses and compares the performance of both well-studied and understudied bird taxa. The thesis describes the selected cognitive tasks, summarises available data and highlights correlations between birds' performances and other factors while discussing possible explanations for their varying performances. Finally, the thesis addresses the question of general intelligence...
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Effects of melanin-based coloration and commensalism on performance in behavioural tests: a comparative study
Kahounová, Hana ; Frynta, Daniel (advisor) ; Šumbera, Radim (referee)
An intraspecific coat colour polymorphism exists in the genus Acomys. Some populations are dark and others are light-colored. Dark populations live in lava deserts, savannas and in the commensal habitat of Egypt. The subject of this thesis is to compare selected populations of Acomys in behavioral test of forced exploration. They are dark commensal, light secondary non-commensal, light non- commensal, and one dark non-commensal populations. The aim of this research is to find out whether the dark commensal populations of Acomys cahirinus differ in behavior from other populations and whether dark populations differ in behavior from light populations. According to the results, the observed behavioral parameters do not show significant differences between populations. The dark commensal populations of A. cahirinus did not differ significantly from other populations in exploratory behavior. But the dark populations preferred a dark background. No apparent differences in behavior between differently colored populations were found. However, the variability in tested behavior between populations was found. Key words: exploratory behavior, melanin, commensalism, comparative approach, open field test, Acomys
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Association between melanin ornaments and behavioural traits
Kahounová, Hana ; Frynta, Daniel (advisor) ; Okrouhlik, Jan (referee)
The work summarizes current knowledge about the melanin-based color polymorphism of integument and its relation to other phenotypic traits in vertebrates. The melanin coloration is the most common type of integument pigment coloration. The biochemical pathway for melanin pigment production can be affected by both genes and environment, which results in coloration polymorphism on intraspecific and interspecific level. The melanocortin system is regulated by genes with pleiotropic activity. Through this pleiotropy the melanin coloration is linked with a number of physiological, morphological and behavioral traits. The work describes the mechanisms of color polymorphism development and the adaptive functions of polymorphism (energy homeostasis, thermoregulation, immune response, resistance to stress and parasites, crypsis). It compares the differences between dark- and lightcolored individuals at intraspecific level: variability in phenotype and in behavior (dark color is generally associated with greater aggression, dominance, sexual activity or exploration rate). Many studies suggest the advantageousness of the dark melanin coloration. So the question remains, why the majority of vertebrates is rather lightcolor. Keywords: melanin , pheomelanin, eumelanin, Melanocortin 1 receptor, MC1R , Agouti...
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