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Factors affecting oetrous cycles in the house mouse (Mus musculus) Abstract This bachelor thesis deals with factors which have significant influence on house mouse (Mus musculus) oestrous cycle. Main theme is oestrous cycle modulation caused by male or female chemical signals. Familiar phenomena like Bruce effect, Whitten effect and Lee-Boot effect are described in detail along with newly explored social modulation issues (ovulation trigger, male genotype role etc.). Environmental impact is also included, especially role of Bisphenol A in connection with negative impacts on human reproduction (tested on mice). Key words: oestrus, pheromone, MUP, Mus musculus, vomeronasal organ

In this study I investigated the dietary preferences of very familiar snake in our country - grass snake (Natrix natrix). I did the experiments with both adults and young individuals. I used Y-maze apparatus for testing. I selected frog (Rana esculenta) and fish of two sizes (Cyprinus carpio) as a prey items for those experiment. I tested snakes in three experimental settings. In the first the prticular snake can choose between empty branch and small fish at the end of the second branch, in the second two fish of different size were offered, and the third experimental setting investigated the preference between small fish and frog. As a prey I used only the cotton rubbed against the prey item (carp or frog) which I subsequently placed to the plastic box at the end of two branches of Y-maze. The results show that the adult snakes are less choosy in their diet than the young snakes which almost always prefer frog prey against fish.