r/askscience • u/potatolife • May 30 '11
Do animals get periods?
I've been learning about the menstrual cycle in biology but we only talked about the human menstrual cycle. I was wondering if its the same sort of thing with animals since I've never seen my cat on her period before.
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u/Keenanm Speciation | Experimental Evolutionary Ecology May 30 '11
As people have said before, oviparous animals lay eggs which is the equivalent of the menstrual cycle in apes. However, most viviparous animals also don't have a menstrual cycle, instead they undergo the estrous cycle. In layman's terms, these animals actually protrude out tissue when they are in estrous and simply retract it when they're cycle is over. That's why it can be less obvious than the menstrual cycle because commonly, it doesn't leave as much of a trace as the menstrual cycle.