Growth Trends and Growth Velocity in Postnatal Ontogeny of Rhesus Macaques (Macaca mulatta) From Konárovice

Abstract

The research project on "Postnatal ontogeny of higher primates" represents a complex study of growth and its regulation and the development of biochemical and hormonal factors, behaviour and social structure and genetic factors in monkeys and apes. It includes also a longitudinal study of 101 regularly examined individuals of Macaca mulatta from 4 to 80 months of age from the Konárovice Primate Center, Czech Republic. The new analysis of individual growth trends and growth velocity shows many important facts. The head segment develops relatively independently in neurocranium features but in correlation with the body height in splanchnocranium ones with steady and marked differences between sexes in all head parameters. An accelerated head growth is relatively longer in macaques in comparison with humans. The trunk and limb segments have similar growth pattern different from head, i.e. neurocranium, growth pattern. Each body segment, i.e. head and trunk segments and limb segments, has a specific pattern of growth different in males and females. Growth acceleration in females starts in prepuberty between 18 and 24 month of age and ceases after 48 month when adolescent period ends. Puberty spurt in males begins after three years of age and it continues till the 5 year. Adolescent spurt starts between 5-6 years of age. An analysis of growth velocities of overall body parameters and the individual segments as well has clearly confirmed this ontogenetic pattern including the growth differences between males and females. There is a marked bimaturation in males and females. Puberty and adolescent spurts express the bimaturation process. The analysis of individual growth curves for 39 rhesus macaques revealed variability of growth patterns in both sexes. We have found an adolescent spurt in most of examined individuals in both sexes. It concerns both the additional growth in size, i.e. body mass and growth of skeleton, i.e. body height, limb segments length and trunk length, in most individuals. Most of the examined individuals show deceleration of growth after the puberty spurt both in body mass and in body height. However, some individuals stop their growth immediately after puberty and some even accelerate growth after puberty. Detailed genetic and physiological analyses are necessary to explain the growth patterns. Like in man the body height is a more precise indicator of ontogenetic changes than body mass. The interpretation of results from Konárovice must be careful because molecular genetic analyses indicate a relatively high degree of imbreeding. Consequently a comparative study of ontogeny of the Konárovice macaques with that of other rhesus macaques is important.