RESPIRATION AND HEAT-TRANSFER

There is little influence of respiration on the heat balance of animals with variable temperature (poikilothermic animals). The same is found for warm-blooded (homoiothermic) animals, which respire air, for the quantity needed for the delivery of O2 is low. However, enormous quantities of water are needed if the O2 is extracted from it. Not even the application of counter flow heat exchangers can reduce the heat losses in a tolerable way. Therefore, homoiothermy and O2 from the water are incompatible. Whales, seals and other warm-blooded animals living in the sea resemble fish in their outward appearance; however, O2 delivery from the water would be unacceptable for them.