Everything You Must Know If Your Dog Gets Knotted: Expert Veterinary Faq
Canine mating diverges sharply from human or feline reproduction. The physical union centers around specialized erectile tissue known as the bulbus glandis, located near the base of the male dog's penis. During initial penetration, the male mounts the female while the penis is only partially erect. Full erection does not occur until the organ enters the female's vestibule.
Once inside, the friction and biological signals trigger rapid engorgement. Venous outflow from the penis temporarily restricts, causing the bulbus glandis to swell into a firm, spherical bulb roughly twice the diameter of the penile shaft. Concurrently, the circular muscles of the female's vestibule (the constrictor vestibuli) contract tightly around this swollen bulb.
This dynamic creates a mechanical lock. The male then dismounts, swinging one hind leg over the female's back so both dogs stand facing opposite directions, joined at the tail. This anatomical lock holds the dogs firmly in place, preventing the backflow of semen and increasing fertilization rates by keeping the sperm pool close to the cervix.
