Common shrews have attracted considerable attention from both ecologists and parasitologists, and have a life history strategy characterized by a high investment in reproduction and a short life span [7] [8] [9] . Their life cycle takes 14 to 16 months to complete, with the first young born in mid-May [10] [11] [12] , and only one breeding season in the spring of the second year of life [9, 12, 13] . Both sexes can mate with multiple partners, and females are extremely promiscuous [14, 15] . Females can produce up to three litters of around seven offspring [10, 11, 16] , with energy intake during lactation increasing to around three times the non-reproductive level [8] . Both males and females die shortly after breeding, such that there is little overlap between generations [12, 13, [17] [18] [19] .