The present paper deals with direct and indirect calorimetric experime
nts on smaller terrestrial and aquatic animals in the range of mg and
g wet weight. Especially, the energy metabolism during development and
growth, under decrease of oxy gen concentration (hypoxia/anoxia) and
with adverse or toxic environmental conditions was studied. The result
s demonstrate the broad versability of direct calorimetry as a sensiti
ve, nonspecific and non-invasive method for investigations of living o
rganisms.