[Biological patterns of the development of lower monkeys during postnatal ontogenesis]

In 840 male rhesus-monkeys relationships between age, height, weight and growth rate were examined. In terms of growth rate the following five age periods were identified in the predefinitive stage of postnatal ontogenesis: childhood--from birth to 9 months of age, adolescence--from 9 months to 3 years, accelerated growth or pubescence--from 3 to 4.5 years, growth completion--from 4.5 to 7-8 years, and physiological maturity (definitive stage)--over 8 years of age. The above age periods derived from growth curves are consistent with the development of the dental system, reproductive organs and other biological signs of postnatal ontogenesis. The relationships between calendar age, height and weight with respect to each age period are described by linear regression equations. The basic patterns of physical development, periods of postnatal ontogenesis and somatometric characterization described above help to objectively monitor the physical fitness of rhesus-monkeys, to adequately select animals identical in terms of their biological age, and to reliably plan long-term studies on this primate species.