Environmental enrichment techniques for black-eared-opossuns (Didelphis aurita Wied-Neuwied, 1826) in captivity

Abstract This study aimed to analyze the efects of environmental dietary enrichment on the behavior of black-eared opossums that were in captivity at Centro de Triagem de Animais Silvestres (CETAS-ES), in the municipality of Serra-ES, from August to October 2022. Two food models were constructed for the study: the “Surprise Tubes” and the “Food Puzzle”. A total of 24 juvenile black-eared opossums were selected, regardless of sex, and divided into eight groups, with three animals each. Then, four groups were exposed to one model and four to the other. Each group was submitted to two conditions: experimental, with the presence of the models, and control, without the presence of the models. Each condition lasted 24 hours and occurred on two consecutive days. They were flmed with a camera trap, resulting in 3,233 videos of 25 seconds. For the elaboration of the ethogram, 24 videos of each group were selected, recorded from 6:00 PM to 7:30 PM, when the animals were more active. The opossums interacted with both models, accessing, and eating the hidden food, preferring meat over fruit. No signifcant diferences were found in the behavior of opossums in relation to the models and it was observed that the aggressive behavior signifcantly decreased when the models were present. It is concluded that the models can be used as an environmental enrichment for black-eared-opossums, bringing benefts to the reduction of aggressive behavior.