Number of nipples varied between ten and twelve in a sample of 51 female edible dormice Glis glis from Slovenia. Ten nipples were by far the most common condition (82 % of specimens) and only two females had twelve. Animals with eleven nipples were asymmetric in the anterior inguinal pair. Three females from Monte Gargano (Italy) had 10, 11 and 11 nipples, but the asymmetric pair was the posterior abdominal one. Since the prevailing condition among dormice (family Gliridae) is eight nipples, it is suggested that high nipple count in the edible dormouse is an ecological adaptation to a multi-annual variation in resources. Due to irregularities in mast-production years, females do not reproduce annually, which possess demands for larger litters. Either the anterior inguinal (Slovenia) or posterior abdominal pair (Italy) is involved in a switch from ten to twelve nipple condition, with the difference possibly showing a geographic pattern.