Gross body composition was studied in 465 captive bank voles during postnatal development (from 1-180 days of life). It was shown that voles from small litters (1-3 young) do not differ from individuals from large litters (4-6 young) either as to degree of adiposis or the average rate of accumulation of the fat-free components of the body mass (FFB). The animals reached chemical maturity at the age of 55-60 days. The level of FFB composition at the stage of chemical maturity is not a species-specific feature and only characterizes local populations. During the first 6 months of development the calorific value of a unit by weight of the protein and fat in bank voles is constant, being respectively 4.583 and 9.240 cal/g.
I. INTRODUCTIONThe large number of studies of Clethrionomys glareolus (S c h r e b e r, 1780), one of the dominant rodents in forest ecosystems in Europe, have contributed to what is known of the features of development and growth of this species in captivity (Sviridenko, 1959; Petrov & Airapet'jans, 1961; Mazak, 1962;Drożdż, 1965) and under natural conditions (Pearson, 1962;N e w s o n, 1963;Bergstedt, 1965;Kubik, 1965; Bujalska & Gliwic z, 1968;Claude, 1970;Crawley, 1970;Zejda, 1971; K a i k u s a 1 o, 1972). These data, however, relate to the biology of the species or to morphological parameters. An exception to this is the study by Sawicka-Kapusta (1974) on the quantitative relations between the main body components in bank voles during the process of growth.Growth is an increase in the mass of the organism, consisting of the growth of tissues of which it is made, and should therefore be considered *) Praca została zrealizowana w ramach problemu węzłowego 09.1.7., koordynowanego przez Instytut Ekologii PAN.[381]