Developmental stages in the howler monkey, subspecies Alouatta palliata mexicana: a new classification using age-sex categories

Abstract

We present a new classification of age-sex categories for the mantled howler monkey Alouatta palliata. This classification includes only those physical and behavioral characteristics that can be distinguished under field conditions, with the goal of being able to infer the approximate age of monkeys in the wild. Our classification is based on data collected ad libitum during monthly censuses of 8 groups of A. p. mexicana in a fragmented landscape on the “Los Tuxtlas” Biosphere Reserve at the northern limit of this species’ distribution. Our new classification system contains 10 categories that can be compared directly to existing classification schemes to facilitate cross-site studies. We compare the results of our study to the currently used classification system which was based on more southern populations of A. palliata in Panamá and Costa Rica.