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

Abstract

This study aimed to analyze the effects of dietary environmental enrichment on the behavior of black-eared opossums that were in captivity at the Brazilian Wild Animal Screening Center (CETAS-ES), in the municipality of Serra-ES, Brazil, 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 subjected to two conditions: experimental, with the presence of the models, and control, without the presence of the models. Each condition lasted 24h and occurred on two consecutive days. They were filmed with a camera trap, resulting in 3,233 videos of 25s. To construct the ethogram, 24 videos of each group were selected, which were recorded from 18h to 19h:30, when the animals were more active. The opossums interacted with both models, accessing, and eating the hidden food, preferring meat over fruit. No significant differences were found in the behavior of opossums regarding the models, and the aggressive behavior significantly decreased when the models were present. It is concluded that the models can be used as an environmental enrichment for black-eared opossums, reducing aggressive behavior.
Palavras-chave: Didelphis aurita; cativeiro; marsupial