Big Little Dog Mating

Breeding dogs of different sizes may be challenging, or worrying even. Indeed, a smaller male may struggle to mount a bigger female; and a small female may be in utter pain with a much larger male. Although dogs are one and only one species, their huge disparity in appearance will raise some understandable questions.

First and foremost, when discussing how to breed two dogs of different sizes, it is important to know if the male is the smaller dog or not. If the male is much smaller than the female, you may require artificial insemination. On the contrary, if the female is much smaller, a c-section might be required as the puppies would potentially be too large for her birth canal. Read our article listing the top dog breeds going through c-sections.

Critical timings for a breeding of dogs of different sizes are the mating itself with the coitus and the delivery of the litter of puppies. However, do not underestimate the strain of the pregnancy that a smaller female would have to endure. Basically, puppies are an average of their parents for most traits, including size. The small female has a uterus designed to accommodate puppies from her breed and will, therefore, become uncomfortable with larger fetuses and whelps.

Can very large breeds mate with toy breeds without assistance?

Strong-willed dogs who hear the call of nature will generally always try to find a way to breed and mate, so it’s possible that it can be done without assistance. However, toy breeds are not physiologically designed to mate with larger breeds, so the process can be clumsy, risky and potentially dangerous. As a firm general rule, you should never leave any dogs to breed without assistance – especially dogs with extreme differences in height– as they can run into problems, especially during the tie process.[pullquote-right]No matter how large the father is, the mother’s uterus is only so big and will restrict the size that the puppies are able to grow to.[/pullquote-right]

It is particularly important not to leave large males and small females alone during coitus as it could cause extensive damage or fatality for the female. She could easily be dragged around by a strong male whilst in lock. She also risks being crushed by his weight or splitting her vaginal opening if the penis is too large. A small female dog who has mated with a large male dog should never have an unmonitored pregnancy as the risk of having puppies that are too big for her to deliver is high.

All breeding between big and small dogs should be closely supervised under the advice of an expert. Both the male and female should also undergo a full medical examination before coitus to ensure that they are fit for the act as it can be a lot more taxing than coitus between two dogs of the same size.

What will be the size of the puppies born from parents of very different sizes?

Puppies will generally get most of their size from their mother because their in utero growth is constrained by the size of the mother’s uterus. No matter how large the father is, the mother’s uterus is only so big and will restrict the size that the puppies are able to grow to. The number of puppies a female is carrying will also affect their size. If she is only carrying one puppy, chances are it will be a lot bigger as it has a lot more space to grow. Whereas, if she is carrying four puppies they can each only occupy a quarter of the uterus and will be competing for space which will limit their eventual body size.

If the puppies have a small father and a large mother, they are still likely to be on the larger size as the mother has a larger uterus allowing them more room to grow. However, their father’s genes will still place limitations of their size and the puppies will be unlikely to be as large as their mother when they reach adult size.

How to Breed a Smaller Male Dog With a Larger Female

In general, if a smaller male dog is determined to mate with a larger female dog, his sexual desire will be strong enough that he will find a way. However, this doesn’t mean there aren’t risks involved and your male dog may need a helping hand. It is best to let him begin proceedings alone but be sure to step in if you see things going awry. It is also best practice to take both sexual partners for a full health check before encouraging them to mate, as any existing health conditions may be exacerbated by the process or may not make them a suitable genetic partner.

The first step your male dog may struggle with is mounting the female. He needs enough height to get up on top of her to penetrate her. If he cannot get high enough, you will need to find a suitable sturdy platform to give him the boost that he needs. Ensure you place it on a non-skid surface and that it has non-skid feet so that your dog will feel sure of his footing. It is also worth introducing the mating partners before the onset of the female’s fertile period (9-14 days after she goes into heat), so they can get to know one another’s smell. This should reduce anxiety levels next time around, meaning that all the dogs’ energy can be focused only on the task ahead.

Once the male has reached a height where he can penetrate the female, he may need some help to stay there. It can take a couple of minutes for the bulbous glands in his penis to begin to swell in preparation for the lock. Whilst this is happening, you can place your hand under his tail and push him firmly up so that his chest lifts onto the female’s back and his feet come off the floor. Hold him here until the male and female are both safely locked.

The next step is possibly the most important as it is where the most damage can occur. The mating lock can take place from anywhere between 15 and 40 minutes. A male dog who is of a similar size to the female will usually lift his leg over the female and turn his back to her. The two dogs will then stand back to back for the duration of the copulatory lock process. However, for a small male dog, lifting his leg over a huge female dog and turning around will not be an easy task. You may need to lift his leg over very gently and help turn him around. This process can seriously injure both dogs if not done correctly.

Once your dog has turned around he will still need some help to stay leveled with the female’s vagina until the lock is complete and he is released. You can place your dog back on his sturdy platform but ensure it is high enough to keep him reasonably leveled with the female as an extreme pulling on his penis may cause damage.

Throughout this process, you may also need to hold the female still so that she isn’t dragging the smaller male around by his penis. Depending on the height discrepancy, sometimes it is enough to just hold the female still throughout the whole process while the male gets to work. You may also be able to encourage the female to lie down on a cushion, so the male can get to her more easily. Never try to force the two dogs apart; always let lock finish naturally. In extreme circumstances, the process can take a full hour so be patient and never leave the dogs unsupervised.


How does a small male dog mate with a large female?

Yes, large dogs can get smaller dogs pregnant. Technically, any sized dog can get any other sized dog pregnant. Fertilization does not care about the size of the dogs involved. However, it is a bit more difficult for highly different-sized dogs to mate.

How do I know if my dog mated?

How do small males mount bigger females? A small dog who is determined to mate with a larger female dog will generally use all his strength and might to try and achieve penetration. However, he may struggle, and he may never get there because he’s simply not tall enough.