Does menstrual cycle also occur in the females of other species of class mammalia?
Not in the same way as in humans, no. Since some people here are obviously confused about what oestrus and menstruation actually are, I will explain. Oestrus, commonly called being ‘in season’ or ‘in heat’, is the only time an animal can become pregnant – it is when the womb lining is thickened in preparation for pregnancy, and the ovaries have either released eggs or are about to release them with the stimulus of mating. In the majority of species, oestrus is the only time the animal feels sexual desire, since it is the only time pregnancy can occur and it would be pointless to mate at any other time. We humans are rare in that we are unaware ourselves of being in oestrus, though it happens once a month – we must work out where we are in our cycle or use ovulation strips to tell us when the best time to try for a baby is. In humans, if a woman does not become pregnant during oestrus, the womb lining and unfertilised egg are discarded – this is menstruation, or ‘having a period’. This
