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Why Do Dogs Get Stuck During Mating? Our Vet Explains

Written by: Dr. Lindsay Bisset BVSc (Veterinarian)

Last Updated on May 9, 2024 by Dogster Team

beagle dogs mating in the garden

Why Do Dogs Get Stuck During Mating? Our Vet Explains


Dr. Lindsay Bisset  Photo


Dr. Lindsay Bisset

BVSc (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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If you have ever watched a male and female dog mate, you may have become worried or even confused at the point when the two dogs appeared to get “stuck” together. This is a result of the copulatory tie. But is getting stuck a bad thing? Is it dangerous? Should you intervene?

Let’s take a closer look at the process of canine mating.

The Copulatory Tie

During mating, a male and female dog get stuck together in what is called the “copulatory tie” or “lock.”1 It occurs when the bulbus glandis, an erectile tissue structure located at the base of a male dog’s penis, becomes engorged with blood. This happens just after the male inserts his penis into the female’s vagina and he begins to thrust.

The bulbus glandis swells quickly and forms a spherical enlargement that’s twice the diameter of the shaft of the penis. The circular muscles located just inside the female’s vagina, called the constrictor vestibuli muscles, contract against the bulbus glandis, completing the lock and preventing the penis from being withdrawn. The two dogs are now tied together.

dog mating
Image Credit: pittaya, Shutterstock

The Breeding Act

Normal mating behavior in dogs begins with the male dog sniffing a female dog that is in heat. If the female is receptive, she will present her hindquarters to him, stand still, and hold or “flag” her tail to the side. The male dog will proceed to mount the female, hold onto either side of her back with his forelimbs, insert his penis into her vagina, and begin to thrust. During this phase, the male dog also ejaculates the pre-sperm fraction of his ejaculate.

It is at this time that the “copulatory tie” happens: The bulbus glandis enlarges, and the female’s vaginal muscles clamp around the bulbus glandis, preventing the penis from being withdrawn. The dog stops thrusting as soon as the “copulatory tie” is achieved and then ejaculates the sperm-rich fraction of his ejaculate.

With their genital organs still locked together, the male dog will dismount and turn 180 degrees, which will result in the male and female facing in opposite directions. The male dog will then ejaculate the post-sperm fraction of his ejaculate over the next 5 to 30 minutes while continuing to stay locked with the female.

dog sniffing ready to mate
Image Credit: High Simple, Shutterstock

What Is the Purpose of the Copulatory Tie?

The purpose of the copulatory tie is to keep the male and female joined together during and after ejaculation. This traps the semen inside of the female and increases the chances that the male’s sperm will successfully fertilize the female’s eggs.

On average, female dogs only go into heat every 6 months, so this strategy helps maximize the chances that conception will occur and the female will produce a litter of puppies.

Does a Copulatory Tie Mean My Dog Is Pregnant?

As with people and other animals, when two dogs mate, it does not always result in pregnancy. Separating dogs that are stuck together during mating will not prevent pregnancy. Contrary to popular belief, it is not necessary for a copulatory tie to occur for a dog to become pregnant, though the tie does increase the chances of conception.

The best way to prevent pregnancy in a female dog is to sterilize her. During this procedure, the female dog’s uterus and ovaries are surgically removed to prevent future pregnancies. This procedure is known as a spay or an ovariohysterectomy.

If your unspayed female dog accidentally mates with another dog, there are mismating injections that can be administered by your veterinarian within 1 to 2 days after mating. Unfortunately, these injections do carry risks and shouldn’t be given too often.

Male,And,Female,Pomeranian_curraheeshutter, Shutterstock
Image Credit: curraheeshutter, Shutterstock

Final Thoughts

Do not interfere with dogs during this process or attempt to separate them, as you can seriously injure both the male and female dogs. Even if one or both of the dogs appear to be in pain or discomfort, it is best to leave them alone until they separate naturally. If it is a dog’s first time mating or they are an inexperienced breeder, they may experience some pain and anxiety during the mating process. You will only make it worse if you try to separate them.

The copulatory tie is totally normal and is an important part of canine breeding behavior. Separation of the male and female will happen naturally once the bulbus glandis is no longer engorged. The copulatory tie lasts anywhere from 5 to 60 minutes.

See also:

Featured Image Credit: curraheeshutter, Shutterstock

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