Thursday, March 26, 2009

Animal Menstruation

Roughly once a month, Carie and I have the same conversation, usually while in the car. It goes something like this:

Carie: God, I hate having a period. It really sucks.
Me: ...
Carie: Do other animals have periods? I've never seen a dog bleed out of its ass.
Me: I've seen a dog bleed out of its ass, but I'm pretty sure it was male.
Carie: ...
Me: Didn't we have this conversation last month?
Carie: Yeah, and I think we were in a car then, too. We need to look this up.

Well, I overcame my innate fear of typing "animal menstruation" into Google and came away with the following information:

From Wikipedia: Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in reproductive-age females of certain mammal species. Overt menstruation (where there is bleeding from the vagina) is found primarily in humans and chimpanzees.[1] The females of other placental mammal species have estrous cycles, in which the endometrium is reabsorbed by the animal (covert menstruation) at the end of its reproductive cycle. Many zoologists regard this as different from a "true" menstrual cycle.

From K-Band: Overt menstruation is recorded in 48 species of primate, most of which are old world monkeys and apes (the group which includes humans). Other primates that overtly menstruate include a few species of new world monkeys and the Malayan flying lemur (Cynocephalus varregatus). Overt menstruation is also occurs in shrews, being reported in 10 species of insectivore from the genera Elephantulus, Erihaceus, Tana, and Tupaia. Other species for which overt menstruation has been reported include four species of bat (Carollia perspicillata, Desmodus rotundus, Glossophaga soricina, and Molossus ater), a marsupial cat (Dasyurus viverrinus), the coyote (Canis latrans), and the African elephant (Loxodonta africana). The reports for menstruation in the coyote and African elephant are anecdotal.

So it looks like it's mostly just monkeys that have a "true" period. Most everything else manages to avoid the messiness, but is probably still pretty crabby nonetheless.

There you have it, more information about animal menstruation than you ever wanted to know.


  1. Oh I'm so glad that's all cleared up now.

  2. Remmember the forbidden fruit. It is all Eve's falut. by the way, next couple of days, watch out for bears.

  3. So Jason's been reading this book on hypnotism (don't ask me why), and tried to tell me about how things like menstrual cramping was "on on a girl's head." I almost pushed him off the chairlift.