Hi there. Great question! Bats are similar to humans in that they give birth to live young and produce milk for their pups while the pup is young. Bats only mate in the autumn and winter though, and the females store the male’s sperm in a special gland over winter. In spring, when it gets warmer, the female self-fertilises herself with the stored sperm. This sounds quite a strange thing to do, but by doing this, females can control precisely when to start their pregnancy so that the pups are born right at the start of summer, coinciding with peak insect (food) abundance. Pretty amazing, right?!