Do dogs menstruate?

Female dogs will secrete red liquid after they become sexually mature (6 to 8 months old). Many owners think that their dogs are menstruating. In fact, this statement is not accurate. Menstruation is only seen in primates such as humans and chimpanzees, while female dogs should be called estrus bleeding.
1. Different from human menstruation, the secretion of female dogs during estrus is not the shedding and bleeding of the endometrium due to the influence of hormones, but the bloody mucus infiltrated by thickened uterine epithelial cells.
2. The cycle of estrus bleeding in female dogs is: approximately twice a year, with an interval of about 6 months, each lasting 21 days (elderly dogs may have longer intervals).
3. Bleeding during estrus in female dogs indicates estrus and pregnancy, while "menstruation" does not ovulate and prevent pregnancy.

What are the symptoms of bleeding in estrus in dogs?
1. Pre-estrus (7-10 days): The vulva is swollen and flushed, the vagina is congested, and red secretions are shed; the person does not want to eat or drink, drinks more water, and is willing to contact male dogs, but does not accept mating. .
2. Mid-estrus (6-14 days): The dog is excited and sensitive, and the mucus flowing out gradually changes from red to light until it is clear and transparent; during this period, the female dog changes from the previous "shy" and takes the initiative to approach the male. The dog, standing still, turns its tail sideways to accept the male dog's climb.
3. Post-estrus (2 months): At this stage, the dog will stop bleeding, the swelling of the vulva will subside, the temperament will become quiet, and the dog will start to be less interested in seeing male dogs.