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).
Cope's arboreal alligator lizard diet, but can begin consuming the same material as their adult counterparts. The major threat to biodiversity for the Cope's arboreal alligator lizard is determined by the IUCN Red List to be the destruction of their habitat. Degradation and fragmentation of their suitable habitat has occurred as a side effect from construction, agricultural formation, and coal mining, as these activities require deforestation in these areas. These lizards are also frequently used in the pet trade, taking them from their native habitats and distributing them around the globe, which also depletes their native population sizes. Their native geographic range in Guatemala