Why can female rabbits become pregnant soon after giving birth?

Female rabbits are able to become pregnant soon after giving birth because they exhibit postpartum estrus, which allows them to conceive immediately following the birth of a litter.1

This reproductive efficiency is further supported by the fact that rabbits are induced ovulators. Unlike many other mammals that follow a regular cycle, a female rabbit's ovaries release eggs in direct response to copulation rather than according to a fixed hormonal schedule. This mechanism, combined with their ability to breed at a young age and produce multiple litters per year, contributes to the high reproductive rates commonly associated with the species.12