Monito Del Monte: Microbiotheria

Colocolos are solitary, nocturnal foragers, both in trees and on the ground. They build and shelter in globe-shaped nests of sticks and water-repelling Chusquea bamboo leaves, lined with moss and grass, in protected areas, and often concealed by a final overlay of gray moss. The nests are about 8 inches (20 centimeters) in diameter. Nest locations may be rock clefts, hollows of trees, or in dense ground shrubbery. The nests are snug and comfortable, but in the coldest months, monitos del monte hibernate, living off fat reserves in the base and first third of the tail.

Since monitos del monte are marsupials, birth and nurturing of the young follow the standard marsupial model: the young are born at an incomplete stage of embryonic development, crawl from the birth canal over the mother's belly fur to the pouch, and there latch onto nipples and remain so, nourished by milk, until they complete their development.

Colocolos mate in the Southern Hemisphere spring and early summer—October through December. A female has a single litter of one to four young annually. Litters of five young have been seen, but since the mother has only four nipples, the fifth cannot survive. On leaving the pouch, the young first reside in the nest, then ride on the mother's back, clinging to her fur as she forages, before beginning to forage on their own. The offspring live solitary lives but continue to associate, off and on, with the mother. The young of both sexes reach sexual maturity in two years. Males remain with females only during the breeding season. The maximum lifespan of this species is probably three to four years.

Colocolos hibernate, intermittently, in their nests, during the cool and cold months, depending on temperature and food availability. Torpor, the low state of body activity in hibernation, is triggered by absence of food over time or by outside temperature. A torpor bout, or period of lowered body functions, may last a few hours to several days (five days is the longest known bout period). Hibernating colocolos rouse themselves spontaneously, probably cued by a temperature increase in their surroundings or a signal from some internal clock. These periods of hibernation, along with the stored tail fat, enable the colocolo to conserve body energy while waiting out periods of low food availability and cold.