Thread: Does an animal's menstrual cycle emotionally affect her?

Many creatures are modest about their excretory functions. Does the same matter apply to another reason among the few types of animals who menstruate? If you were to encounter a bat or monkey when she had her period, then would she be embarrassed? Do these cycles cause shifts of mood in animals? I'm referring to general emotional states, not mating.

Originally Posted by Theresa

Many creatures are modest about their excretory functions. Does the same matter apply to another reason among the few types of animals who menstruate? If you were to encounter a bat or monkey when she had her period, then would she be embarrassed? Do these cycles cause shifts of mood in animals? I'm referring to general emotional states, not mating.

I am no expert (or even passably knowledgeable) in this area but wonder why you use the word "modest" in your question.

Are you implying that they may be complying with some kind of social expectation if this behaviour was to be observed?

I can imagine possible situations**where a female might wish to keep her menstrual status below the radar but wonder about the practicalities of such a subterfuge.

** Could she perhaps seek to favour one male over another or perhaps protect her young offspring from an interested male that might harm them?

Originally Posted by Theresa

Many creatures are modest about their excretory functions. Does the same matter apply to another reason among the few types of animals who menstruate? If you were to encounter a bat or monkey when she had her period, then would she be embarrassed? Do these cycles cause shifts of mood in animals? I'm referring to general emotional states, not mating.

I think you are anthropomorphising. Animals are not "modest". They often find a quiet place to excrete because they are vulnerable to attack while they are doing it. That is probably the original reason why humans do the same. Obviously this can't apply to menstruation, as that takes place gradually, over a far longer period of time, during which the animal remains fully active.

By the way your question motivated me to find out why only a very few placental mammals menstruate. It seems to be to do with the degree to which the endometrium (lining of the womb) thickens in the expectation of an embryo implanting itself. Most mammals only do this a bit and the extra lining is reabsorbed each cycle, rather than being shed. Exactly why humans, some apes, bats and the elephant shrew, but no other mammals, grow such a thick endometrium that it has to be shed if it is not used, does not seem to be clear.