Early postnatal physical and behavioural development of degus (Octodon degus)

6 litters of Octodon degus were studied from birth to 10 days of age. Newly-born degus (mean weight 14.6 g) had open eyes, upper and lower pigment, fur, and teeth. Within 3-4 hours of birth they were able to walk supporting their full weight, right themselves rapidly, sit upright on their haunches, or rear upright with support, and vocalize. By the 1st or 2nd day, the young animals displayed functional grooming (face washing, hind-paw scratching, rapid head-shake). Solid food was ingested from day 6, although newborns chewed wood chips and 3-day olds gnawed dried faeces. Young degus were tested daily in an open field apparatus and showed increased activity and exploration, with repeated testing while decreasing distress vocalization after the 4th or 5th day. Degus are proposed for the study of developmental topics since their degree of development at birth allows for immediate testing. The degus studied here seem to be more fully developed at birth than those studied in Britain.