Animal responses to extreme conditions: a lesson to biomedical research

Various animals must cope with some specific extreme environmental conditions and, as a consequence, they developed extremely efficacious adaptive defence responses. The mechanisms of the specific defences are more clearly visible in some species than in humans. Therefore, animal models of the human defence mechanisms should be selected accordingly. The appropriate, well responding models may be regarded as "biological amplifiers". This review is focussed on examples of effective defence against: (i) parturitional asphyxia, which extends fertility of mammals; (ii) diving asphyxia, which extends access of food in aquatic birds and mammals; (iii) endotoxemia, which provides survival of the fittest in mammals showing top fertility; (iv) deep hypothermia, which enables hibernating mammals to arouse. Each of the defences needs close co-operation of the cardiovascular, respiratory and temperature regulatory systems. Underlined problems regarding a choice of appropriate experimental animal models should stimulate renaissance of comparative physiology.