Question

Why do dogs and cats have estrous cycle but human beings have menstrual cycle,though all are mammals?

Answer 1

Menstrual cycle is not the characteristics of mammals.Dogs and cats are non primates thats why they have oestrus cycle and humans are primates so they have menstrual cycle.

Answer 2

Answer:

The dogs and cats are non-primates.

Explanation:

Dogs and cats are non-primates and menstrual cycle occurs in primates only. Menstruation is the exfoliating of the endometrium if fertilization does not befall -- maximum creatures reabsorb the endometrium preferably than discarding it. And as cats and dogs are not primates this is why they have an estrous cycle instead of a menstrual cycle.