Factors affecting body mass of young fat dormice (Glis glis) at weaning and by hibernation

This paper describes the factors affecting body mass at weaning and by hibernation of young fat dormice Glis glis We studied a free‐living population in 1991 and 1992 in a mixed forest where 100 nest‐boxes were placed. In the two years, 128 females used the nest‐boxes to give birth and rear their litters and more than 900 dormice have been individually marked. Body mass of young at weaning was positively correlated to body mass of the mother in both years and to birth date in 1991, while litter size was negatively correlated to body mass of the young in 1992 only, when birth took place about two weeks later than in 1991. On the contrary, by the time of hibernation, young born later weighed significantly less than those born earlier in the season, and heavier young at weaning remained heavier by hibernation, while maternal body mass and litter size did not significantly affect body mass of young at this stage. Body mass of the mother was negatively related to the date of parturition and...