Other species don’t bother menstruating because they retain their womb lining. We are in a minority among species, and among mammals, to bleed every month. The only other animals known to menstruate are apes, Old World monkeys, the elephant shrew, and four varieties of bat including Desmodus rotundus9 (which I cite because it is a vampire bat, and its name means “two-thirds of the way around”).
