An inbreeding population of golden hamsters (lab hamsters), witch was founded in 1930, were compared with an outbreeding population, derived from 16 wild animals from 1998 (wild hamsters), upon to an age of 70 days. 77 lab and 115 wild litters were examined. After weaning at day of life (DL) 28 314 animals of each population for the comparison of further characteristics were used. For the traits after DL28 heritabilities were estimated. For both the trait comparison and the estimation of heritabilities mixed linear models were used. It turned out that the wild hamsters had larger litters at DL01 and the youth grew at the beginning of life faster than the lab hamsters. From DL25 the lab hamsters increased faster in mass. The population differences in the body composition, determined at DL70, could be explained with differences in body mass (BM). At DL70 testes and spleen of the lab hamsters were heavier independently of its higher BM. The mass of epididymis, kidneys and adrenal glands (here with exception of the values of the lab males) were not significantly different. The adrenal glands of the lab males were heavier than those of the other groups, which could not be explained by its high BM. At DL57 the corticosterone concentration of feces, at DL70 concentration of the blood was examined. In the comparison of the females the wild hamsters, in the comparison of the males the lab hamsters had the higher concentrations. Using running wheel, open field and elevated plus maze the behavior of wild and lab hamsters was compared. The wild hamsters showed higher activity and anxiety than the lab animals. In nearly all traits the tendency to smaller heritabilities in the lab population could be observed. This speaks for smaller genetic variability. The population differences in the examined traits let assume that the lab hamsters were bred in their past regarding large litters.