Dogs in heat, rutting stags and cats in season: animals make it very clear when they’re most fertile. Sometimes this involves a bit of blood. With humans it’s exactly the opposite.
All mammals have a menstrual cycle. But most of them have a covert menstruation. This means the endometrial lining is so thin; it gets completely absorbed by the body if the egg isn’t fertilised. Humans, primates and some other mammals (bats, African elephant shrews and certain tree shrews) have such a thick endometrial lining that part of it is being shed through the vagina.
The bloody discharge you see in female dogs, and sometimes also in cows and species of the horse family, has to do with the ovulation: blood vessels in the vagina wall burst because of the blood pressure. This bleeding is no menstruation. Besides, animals can be quite moody when they’re fertile. Just ask any horse owner with a mare in the stable.
More?
Monkey on her period
Periods at an early age, why?
Menstrual synchrony: fact or fiction?
October 24, 2018 at 6:18 pm
cool!
February 8, 2019 at 7:07 am
I really appreciate with this website. Thanks for educating people
May 31, 2019 at 12:10 am
So they do or don’t lol. Pretty sure Guinea pigs n hammies have periods too.
June 25, 2019 at 5:07 am
Research well done. Thumbs up guys!
April 12, 2020 at 10:53 am
Thanks a lot! Keep up the good work.