Reproduction
The Eurasian water shrew is a dioecious organism that engages in sexual reproduction (gametic meiosis). Mating usually occurs during the months of April and September. The period of gestation for females is approximately three weeks. The average liter size can range from three to ten offspring, each of which weighs approximately one gram. Each female usually has two litters per year. The offspring don’t reach sexual maturity until they are approximately seven months old. The average life span of the Eurasian water shrew is approximately three years.
Under experimental conditions, females seemed to be aggressive
towards males during the entire pregnancy period. Females even
showed aggression towards males even after the offspring were born
and had left the nesting area. Mother's remain with their offspring
until the lactation period ends, which is approximately a month.
After lactation ends, the mother avoids the offspring and eventually
runs away.
