Short communicationIs reproductive strategy of Alpine mountain hares adapted to different elevations?

In Lepus, litter size is inversely related to the duration of the reproductive season resulting in a consistent yearly production of around ten leverets per female. In high latitudes, animals have few litters with large litter sizes, whereas in low latitudes, several litters with small litter sizes are common per year. Knowledge on reproductive performance of Alpine mountain hares (Lepus timidus varronis) is scarce. In this study, we analysed 89 hares from Grisons, Switzerland, by examining placental scars and eye lens weight. The general aim of the survey was to examine the reproductive performance of female Alpine mountain hares. In particular, we focused on the question whether this subspecies adjusts the reproductive strategy in relation to elevation such as other Lepus species do in relation to latitude. All adults of our sample reproduced. 39% of the females littered twice and 61% three times a year with a median litter size of 3.00. We identified a significant effect of elevation on litter size, whereas the elevation did not influence the number of litters. We found no significant difference of yearly reproductive output across elevation range. Hence, some reproductive parameters seem to indicate that the Alpine mountain hare changes the reproductive strategy in relation to elevation similar to the mountain hares living further north do in relation to latitude.