Physical and behavioral aspects of sexual maturation in male golden hamsters

Male golden hamsters (Mesocricetus auratus) were examined from 3 to 9 wk of age for morphological, physiological, and behavioral indices of sexual maturation. Although each of the eight variables selected for measurement displayed a unique developmental profile, a principal-components analysis of these variables resulted in the extraction of two principal components, one tentatively labeled physical and gross behavioral maturation (accounting for 66% of the total variance) and the other designated perfection of mounting orientation (accounting for an additional 12% of the variance). This result indicates that puberty in the male hamster is best viewed as two independent processes, rather than as a unitary process, or as an arbitrary term applied to a variety of unrelated developmental phenomena. Advantages of using multi-variate composite scores and selected univariate measurements are discussed; as are methods of comparing developmental changes in different variables. A second experiment confirmed an unexpectedly early onset of androgen secretion and an unusual pattern of body weight gain.