Brazilian gracile opossum habitats than more purely arboreal animals. It has also been found in artificial plantations. There are no recognised subspecies. Brazilian gracile opossums are arboreal and nocturnal, spending the day nesting in tree hollows. They are solitary animals, with each individual inhabiting a home range of anything from , depending on habitat. Males tend to have larger home ranges than females, presumably because, being larger, they require more food. The species is insectivorous, and is an opportunistic forager, not specialising in any particular kind of insect. Individuals have also been reported to eat some spiders, snails, and even fruit (including passionfruit).
Divergent evolution in animals insects are believed to be a result of needing the ultrasonic hearing that tympanal ears provide in order to hear predators in the dark. Non-nocturnal insects - that do not need to fear nocturnal predators - are often found to lack these tympanal ears. Animals undergo divergent evolution for a number of reasons. Predators or their absence, changes in the environment, and the time at which certain animals are most active are chief among them. A lack of predators – predatory birds and mammals - for cliff-side nest residing kittiwake caused that particular group of kittiwake to lose their ancestral