People search on Google for an answer to the question: “do cats have periods?”. This is my attempt to answer it.

The menstrual cycle includes the release of a nutrient-rich lining (endometrium) within the female’s uterus if pregnancy does not occur. This is menstruation. The word “period” is a euphemism for menstruation. The endometrium is designed to cushion and nourish the developing foetus if one develops.

Menstruation occurs periodically. It occurs in the females of certain mammals; one of them, of course, being humans. In humans the “period” can be seen (it is “overt”). This form of menstruation is thought to almost exclusively occur in primates of which the human is one species. It also occurs in bats and the elephant shrew.

Females of other species of mammal advertise their fertility when they go into heat or oestrus. At this time they’re receptive to copulation. If fertilisation does not take place the endometrium is absorbed by the uterus. Some people refer to this as “covert menstruation” (hidden period).

A cat is a species who has heat (estrus) cycles whereas humans have menstrual cycles. Animals (including humans) that have menstrual cycles shed the endometrium whereas animals that have estrus cycles reabsorb it.

Therefore, the answer to the question, in the title to his article, would appear to be that cats do have periods of a sort but they are hidden. The difficulty in using the word “period” in reference to the domestic cat is that the word was created by humans for humans. Therefore strictly speaking it is inapplicable to cats.

Note: vaginal discharge in cats and dogs is not a period.

Source: Wikipedia for the fundamentals! If I have this wrong please tell me in a comment. I wish a woman had written this for me 😉 .