Gracilinanus agilis
agile gracile mouse opossum

This opossum is found from eastern Brazil to eastern Peru and northern Argentina.

This opossum lives in forest habitats.

Head-body length averages 110 mm while tail length averages 137 mm. Males and females are similar in size. Their tails are naked and prehensile. Mouse opossums have an opposable big toe on their hind feet, which allows them to rapidly climb thin vines. Their opposable toes lack claws. They have very mobile, membraneous ears.

Females produce two litters annually. A female's first estrus occurs at 265-75 days. Gestation lasts about 20 days. A female has 13 teats, but not all teats are functional. The maximum litter size is 11; average 7-9. The weight of each newbornis less than 250 mg, and the young are extremely altricial at birth. This species lacks a pouch. After the young are born, they crawl up the mother's belly and attach themselves to a nipple. Weaning occurs at 60-70 days. The young leave the mother a few days after they have been weaned.

These opossums are solitary animals. They hunt and nest alone. They live in dens or in nests that they have taken over from other species.

These opossums are omnivores, feeding mainly on insects and soft fruits. They are nocturnal.

When threatened, this opossum feigns death. Because they are nocturnal, hearing is an important sense.

This particular species is occasionally found as stowaways in banana shipments. When bananas are shipped, they are kept at a relatively cool temperature. Mouse opossums fall into a hibernation-like state at low temperatures. Their respiration rate, metabolism, and need for food are decreased, allowing them to survive the cool temperature of the banana shipments.