[Behavior of pet animals].

Severe mistakes in pet keeping are often the result of ignorance. Many animals suffer from the care of their owners. Industry provides food in the proper composition, but the importance of the cage's interior, its size and the number of animals of the same species kept in it is often neglected. The key to a better understanding of pets is the knowledge of the ecological environment of their species. Fish, amphibia and reptiles are capable of simple acts of learning, but their potential of adaptation to their environment is determined mainly genetically, which can be observed best during the phase of their youth. Most members of these animal groups are born with a perfect behaviour program. Thus aquaria and terraria should as far as possible correspond to the needs and requirements of the species in question to its ecological niche. An aquarium should be a model of the animals' biotope. The effect of the conditions under which a pet is kept on its wellbeing is discussed in detail for the budgerigar and the guinea pig. Experiments with budgerigars showing that too small cages and the missing company of animals of the same species lead to abnormal behaviour are described. Guinea pigs live in packs. The fact how important the group and its social organization is for the individual guinea pig is documented by experimentally verified data. Furthermore the effect of the guinea pig's ontogeny under experimental conditions on the structure of a pack is discussed. Already small changes in the size of the cage or in its interior encourage the guinea pig's exploration behaviour and its mobility.