[Animals as models in experimental gerontology--comparative aspects]

In experimental gerontology animal models are of fundamental importance in further development of knowledge. The comparison between different models and between model and conditions in man depends on the individual position in the hierarchy of phylogenetic evolution and the examined process. In comparison with man short lived mammals are the most useful models. Nevertheless the comparison with more distant classes and species offers an additional insight and a more critical consideration of basic processes and of hypotheses of ageing in the general understanding of biological ageing.