Sexual Maturity in the Captive Male Bandicoot, Isoodon-Macrourus

Abstract

Various morphological and physiological features were examined weekly in developing male bandicoots, each housed with a mature female, from birth through to the fathering of their first litter. The first peak of plasma testosterone greater than 2 ng ml-' in the male was observed at 179.8 ± 6.8 d old (mean ± SE; n = 17); sperm were first observed in the male reproductive tract at approximately 200 d old and this coincided with the pigmentation of the scrotal skin at 199.5 ± 8.2 d (n= 10). The first litters were sired at 349.7 ± 14.0 d (n=7). Male bandicoots reached sexual maturity approximately 100 d later than females. Pigmentation of the scrotum would appear to be a useful indicator of the stage of sexual development because it occurs at the stage of development when sperm first appear in the reproductive tract in the male bandicoot. Nevertheless, the appearance of sperm and scrotal pigment, both precede sexual maturation by at least 150 d and are not good indicators of reproductive ability in the male bandicoot.