The Brazilian guinea pig lives in small groups, usually consisting of a single male and one or two females. While each group occupies a separate nest concealed amongst brush and vegetation (3) (4), they share a complex network of tunnels and runs—constructed through the dense undergrowth—with the numerous groups that live close by (2).
The Brazilian guinea pig primarily grazes on grass, but will also take leaves, seeds, flowers and bark (4). Being highly vulnerable to predators, this species feeds at dusk and dawn, never more than a few metres from cover, and with the group continuously on the alert for potential threats (2) (5). Predators mainly comprise birds of prey and South American mustelids, such as the greater and lesser grison (5).
Although the Brazilian guinea pig breeds throughout the year, most births usually occur between September and April. Females can produce up to five litters in a single year, generally producing an average of two pups per litter after a gestation period of around 62 days (1). The young are born extremely well-developed, and on the first day are able to run and eat solid food, although they normally suckle for three weeks (2). Brazilian guinea pigs become sexually mature after just 30 days (2), and may live for around 8 years in captivity (3).