Yellow-sided Opossum

This species displays a rich repertoire of stereotyped behaviors. Postures, locomotion, and grooming are similar to those of other didelphids. They carry nest materials using their short but still prehensile tails.

Both males and females hunt insects and small vertebrates, and show specialized behaviors for dealing with difficult prey. Large insects are attacked rapidly and the head is consumed first. In contrast, hairy caterpillars are not immediately grabbed; instead, the opossum scratches the caterpillar to get rid of the urticating hair. Small mice are rapidly chased and attacked until a firm bite at the neck is attained, similar to the throat clamp used by large carnivores. M. dimidiata has been proposed to be a miniature analog to the marsupial sabertooths Thylacosmilus. Like extinct sabertooth predators, it has one of the largest canines of any marsupial relative to body size and was proposed as a living model to test hypotheses about hunting strategies of the extinct predators. Yellow-sided opossums also show a variety of behaviors used in social contexts, including male-to-male agonistic rituals, and a variety of vocalizations whose social or adaptive significance deserves further investigation. The species is one of the few mammals in the world that shows an annual semelparous life history. …