Due to the very important role in Brazilian ecosystems, studying the anatomy of opossums is extremely relevant for their natural preservation and possible clinical and surgical interventions with captive animals. These marsupials occupy diversified niches being well distributed throughout the Brazilian territory. They collaborate in the control of urban and agricultural pests such as rodents and insects. They are also excellent dispersers of seeds through their feces. The conclusion is that opossums can be a great model for the study of the anatomy of wild animals.