>>713611346>Do other female mammals bleed out of their vaginas on set times?All mammals have hormonal estrus cycles, where the endometrium thickens but is later reabsorbed.
Only primates, some mice and elephants have menstrual cycles, where the endometrium thickens but is then shed and discarded instead of absorbed.
And from these, only humans and chimpanzees shed enough endometrium to visibly bleed.