Table 1. The reproductive potential per breeding season of female European brown hares with and without superfetation.

	Without superfetation	With superfetation
Interval between successive deliveries	42 days	38 days
Maximum number of gestation periods	1+[(252*−42)†/42]=6.0	1+[(252*−42)†/38]=6.5
Mean litter size (observed)	2.5	3.2
Mean number of offspring per season from second litter onwards	5.0×2.5=12.5	5.5×3.2=17.6
Mean number of offspring per season (all litters)	12.5+1.9‡=14.4	17.6+1.9‡=19.5
*The mean duration of the breeding season in the captive colony from the first date of conception until the last date of parturition across all study years.
†Excludes the first pregnancy of the season that cannot be conceived by superfetation.
‡Mean litter size of first pregnancy per season in January and February was 1.9 ± 0.1 offspring (n=61 litters from 41 females).