Isolation has permanent effects upon the behavior of the rat, but not the mouse, gerbil, or guinea pig

In the rat isolation has both short- and long-term influences upon behavior. Rats isolated at any age will show increases in timidity and aggression, but both effects can be reversed by periods of social housing. However, isolation before 50 days of age has permanent effects upon behavior. We have previously found that rats between 25 and 45 days of age may be protected from the deleterious effects of isolation by short daily periods of social...