The ability to arrange with conspecifics depends on social experiences around puberty.

The study examined the effect of age on the ability to arrange with unfamiliar conspecifics in differentially reared male guinea pigs. The experiments were conducted with 50-, 90-, 150-, and 210-240-day-old-males, which either had been reared in large colonies (CRM) or each with a single female (FRM). In each age class, seven pairs of unfamiliar CRM and seven pairs of unfamiliar FRM were placed in chronic confrontations for 6-10 days in the presence of an unfamiliar female in 2 m2 enclosures. Body weights were determined directly before and 52 h, 124 h, and 220 h after the onset of the experiments. CRM showed no substantial losses in body weights irrespective of whether the experiments were conducted before, around, or after sexual maturity (which is achieved at 2-3 months of age). In contrast pairs of FRM arranged without problems only at 50 days of age. Around puberty, social stress distinctly increased, and 2 and 4-5 months later the confrontations even had to be ceased after 6 days, because losers extremely decreased in body weights. It is concluded that in male guinea pigs the time around sexual maturity is crucial for the development of social skills necessary to arrange with unfamiliar conspecifics in a nonstressful way.