Six colony (CM) and six individually reared males (IM), aged 7 to 8 months, were singly introduced into unfamiliar colonies of conspecifics for a period of 30 days. CM easily adjusted to the new social situation: on the 1st day they explored the new environment but did not court any female thereby avoiding attacks from the male residents. In the course of the following days they gradually integrated into the social network of the established colonies and could even gain higher ranking social positions than those which they had had in their natal colonies. On the CM 1st, 3rd, 6th, 10th and 20th day in the new colonies, changes could not be determined in either their body weights or in their plasma concentrations of glucocorticoids, androgens and norepinephrine. In contrast, IM responded to the new situation with substantial decreases in body weight as well as with extreme increases in plasma glucocorticoid concentrations. We conclude that CM, in comparison to IM, can integrate well into strange colonies because they acquire appropriate behaviour through rearing in their natal colonies.