AGE ESTIMATION OF THE GRAY 4-EYED OPOSSUM, PHILANDER-OPOSSUM (DIDELPHIMORPHIA, DIDELPHIDAE)

Variation of body mass, size of head and body, tail, and developmental traits were observed during the life of Philander opossum reared in laboratory in order to establish a method for age estimation. The morphometric data were fitted empirically to a exponential curve, for the pre-weaning phase, and to a logarithmic curve, for the post-weaning phase. External morphological traits, in the pre-weaning phase, and dentition stages, in the post-weaning phase, were transformed in discrete units and multiple regressions were calculated as empirical estimators of age for each phase. These methods had acceptable experimental errors and can be used to estimate age in field studies.