While most female mammals have an estrous cycle, only a few species experience menstruation). Menstruation is generally considered to be limited to primates, and overt menstruation (where there is bleeding from the uterus through the vagina) is found primarily in humans and close relatives such as chimpanzees). However, some non-human animal species do menstruate, including:
- Apes: Apes experience menstruation cycles.
- Old-world monkeys: Old-world monkeys, such as macaques and baboons, also experience menstruation cycles.
- Elephant shrews: Elephant shrews are a small group of mammals native to Africa that have a menstrual cycle.
- Bats: Menstruation has been observed in a few species of bats.
It is worth noting that many other species have menstrual cycles, but they reabsorb the old womb-lining rather than bleed it out. The reasons behind the two strategies are unclear.
