Octodonts: Octodontidae

All but one species of octodont are nocturnal, meaning they are most active at night. Degus are diurnal, meaning they are most active during daylight hours.

Octodonts are extremely talented and organized diggers. They build burrows consisting of many branched tunnels and multiple entrances. When digging a burrow, the adults form a chain that speeds up the activity. Most octodonts, such as degus, coruros, and rock rats exhibit a complex system of social behavior, living in colonies of five to ten adults and their young. They groom each other, lay bunched together when sleeping, and the females nurse each other's babies. Other species of octodonts are solitary.

The mating system for octodonts is not well understood although in several species it appears to involve courtship rituals. Most species, including the degu and coruro, usually breed twice a year. Females reach puberty, the age of sexual maturity at which they can bear offspring, at six months. The gestation period, the amount of time the young are carried in their mother's womb, is seventy-seven to 105 days. Litters usually consist of four to nine babies.