Why do dogs get stuck when mating? Vet reveals everything you need to know

Two dogs mating on the beach
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Why do dogs get stuck when mating? It's a question you may be asking if you've ever noticed two dogs unable to separate after they've done the deed. But rest assured, while it can certainly freak you out if you've never seen it before, it's completely normal. 

If you've ever been at the park with your pup playing with the best dog toys and spotted two dogs stuck together, or you've witnessed it with your own dog, you may be wondering what on earth causes this strange situation! In basic terms, dogs get stuck together after mating when the male's swollen penis becomes gripped by the contracting muscles in the female's vagina. 

The good news is, this is nothing to worry about. If you don't want your female pup to breed, you'll want to read up on how long a dog stays in heat so that you can avoid them being off-leash during this time or consider spaying or neutering your female or male dog. 

But if you plan to let your dog mate, you'll want to stick around as Dr. Rebecca MacMillan goes into more detail about why dogs get stuck together when mating, how long it lasts, and what you should do when it happens. 

Dr Rebecca MacMillan
Dr. Rebecca MacMillan

Rebecca is a vet surgeon who graduated from the Royal Veterinary College in 2009. She has a wealth of experience in first opinion small animal practice, having done a mixture of day-to-day routine work, on-call emergency duties and managerial roles over the years. She enjoys medicine in particular and she is proud to have recently achieved a BSAVA postgraduate certificate in small animal medicine (with commendation). She writes on various feline and canine topics, including behavior, nutrition, and health. Outside of work and writing she enjoys walking her own dog, spending time with her young family and baking!

Why do dogs get stuck when mating?

If you're anything like us, you may not have even been aware that dogs could get stuck together while mating. Or, if you were aware, you may be curious as to why it happens. 

According to Dr. MacMillan, while two dogs being unable to separate after mating may look like a cause for concern, it's actually completely normal and nothing that you need to be worried about.

"Dogs get 'stuck' during mating because the gland at the bottom of the male's penis swells up and becomes gripped by the contracting muscles in the female's vagina," MacMillan explains. "This forms a 'mating tie' or 'copulatory tie' whereby the two dogs are locked in position until the swelling subsides. A tie indicates a good mating has occurred, which carries with it more chance of pregnancy. 

After the initial mating, the male dog may step over the female dog while they are still tied so that they are facing away from each other (in a bottom-to-bottom position). This is all a perfectly normal part of canine mating behavior, even if it looks a bit strange to us!"

If you have a female dog and you don't want them to breed, here are the five signs your dog is in heat so you can keep them safe and comfortable during this time.

What is the purpose of the copulatory tie?

Two beagle dogs outside

(Image credit: Getty Images)

When the gland at the end of the male's penis swells up and is gripped by the contracting muscles in the female's vagina, it forms what's known as the copulatory tie — and its purpose is quite simple, as MacMillan explains:

"It is thought that the purpose of the copulatory tie is to keep as much semen inside the female as possible. The male's penis acts like a plug, meaning there is more chance of sperm staying in the vagina and going on to reach the egg. As female dogs are only fertile twice a year, the stakes are high to achieve a successful pregnancy! A tie helps increase the chances of this occurring."

Does a copulatory tie mean my dog is pregnant?

A tie is often seen as a sign of successful mating, but it doesn't necessarily signal a pregnancy. 

"A copulatory tie does not guarantee that your female dog will become pregnant," says MacMillan. "Many factors affect fertility, including the health status of both the female and male dog and the timing of the mating. 

If you want to confirm a successful mating, then a checkup with your vet and a pregnancy ultrasound scan will help to confirm this. If the mating was accidental and the pregnancy is unwanted, then don't leave things to chance — speak to your vet sooner rather than later for advice on what can be done."

It's also important to note that dogs don't necessarily need to become tied together for a pregnancy to occur. Slip mating, where the male's penis may come out of the female's vagina before they've tied, is possible and can still result in puppies. 

There aren't many things to hate about being a dog owner, but an accidental pregnancy is certainly one of them, so as MacMillan says, be sure to discuss the situation with your vet who will be able to offer guidance and support.

How long do dogs stay stuck together after mating?

There are some things you only know if you're a dog owner, but even we weren't sure how long dogs stay stuck together after mating. Thankfully, Dr. MacMillan was able to enlighten us! 

"The length of time that dogs can stay tied is very variable," she says. "For some, this may only last a few minutes, whereas for others it could be up to an hour. It all depends on how quickly it takes for the swelling to subside."

You might be concerned about your dog being in pain during this time, but according to MacMillan, while it can be uncomfortable (especially for dogs who haven't experienced it before), it shouldn't be painful.

"Being in a copulatory tie should not be painful for either dog, but some may start to become restless or anxious if it goes on for a little while. This is especially true in inexperienced dogs. Calmly holding and reassuring your dog may help with this until they can leave the tie."

What to do when dogs get stuck while mating

Two dogs outside

(Image credit: Getty Images)

If your dog becomes tied to another dog after mating, you may be tempted to separate them. However, according to Dr. MacMillan, it's important you don't attempt to do this. 

"You should never try to separate two dogs that have tied. This could cause them
considerable pain and stress," she says. 

"So even if the mating is accidental, you should just wait until the tie comes to a natural end and the swelling has subsided — never force them apart. If you are concerned about your pet or if this is an unwanted pregnancy, then you should contact your vet for advice after the event."

Looking for more great canine content? Check out why do dogs lick their butts and why do dogs roll in poop for answers to why our fur friends do the weird things they do!

Kathryn Williams
Freelance writer

Kathryn is a freelance writer who has been a member of the PetsRadar family since it launched in 2020. Highly experienced in her field, she's driven by a desire to provide pet parents with accurate, timely, and informative content that enables them to provide their fur friends with everything they need to thrive. Kathryn works closely with vets and trainers to ensure all articles offer the most up-to-date information across a range of pet-related fields, from insights into health and behavior issues to tips on products and training. When she’s not busy crafting the perfect sentence for her features, buying guides and news pieces, she can be found hanging out with her family (which includes one super sassy cat), drinking copious amounts of Jasmine tea and reading all the books.

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