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. The size difference can make the act of mating a bit difficult, so there is less of a chance that it will happen naturally.
Dogs tend to be quite persistent, though. If a male and a female dog are left unsupervised when the female is in heat, there is a good chance that a litter will occur – even if there is a significant size difference between the two animals.
There are serious medical concerns when a small female becomes pregnant by a large male. Because the male is larger, the fetuses likely will be as well. This larger size can cause all sorts of health concerns for the female during pregnancy and birth.
For that reason, it is not recommended that females carry the puppies of larger dogs. If breeders are trying to combine two breeds of different sizes, they often artificially inseminate a larger female with the sperm of a smaller male. This process is much safer for the female and puppies.
If a female accidentally becomes pregnant by a much bigger male, there are many critical medical decisions that you may have to make.
Health Concerns When Breeding a Larger Male with a Smaller Female
Whether it was purposeful or not, several problems often arise when a small female is carrying the puppies of a substantially larger male.
During the Mating Process
First, there are potential health problems with the act of breeding itself. If the size difference is significant, the male could potentially seriously injure the female when attempting to breed with her.
The breed of the female does matter – not necessarily just the size. Some petite females have sensitive spines and are prone to things like intervertebral disk disease (IVDD). While this isn’t an issue in regard to mating with a dog of a similar size (usually), it can be a problem with much bigger males. The male could potentially injure the female’s spinal column, causing pain and paralysis.
In most cases, the female won’t have to hold up the whole weight of the male. However, when the size is substantially different, this doesn’t always matter.
Some males are rougher during the mating process than others. There is often a lot of pawing and gentle biting going on. Usually, this doesn’t cause significant injuries to either dog. However, when the male is larger than the female, this pawing can cause injury.
It is also possible for the male’s penis to be much too large for the female. Attempts at mating could result in the female’s vagina being ripped or otherwise mutilated.
If the male successfully penetrates and forms a lock, the dogs must be kept very still. The weight of the female will not keep the larger male in place. He may very well decide to run around the yard, dragging the distressed female around with him. As you can imagine, this situation can be highly distressing for the female – and potentially even be fatal.
The male may also decide to lay down after the lock, potentially squishing the female if she is too small. It is unlikely he will turn around and navigate away from the female if she is exceedingly tiny.
Pregnancy and Birth
If the mating goes successfully without hurting the female, you still aren’t out of the woods. Pregnancy and birth can be hazardous for the female.
As you’d likely guess, a female’s uterus and birth canal are made to accommodate puppies of her breed. When you breed her with a giant dog, there is a significant chance that the fetuses will be larger than her uterus and birth canal can accommodate.
There is a significant possibility that she will need a C-section to deliver the puppies. Most of the time, they’ll be too big for her to push out of her body. Without intervention, the females and puppies will die.
Luckily, the puppies will not grow too big for the female’s uterus. Their size will be constricted somewhat by the female’s size. They can’t grow bigger than the female is; it isn’t possible.
The more puppies the female is carrying, the better. When there are more puppies, their growth is restricted even more since they have to share the space with other puppies. Sometimes, this growth restriction is enough to make the puppies small enough for standard delivery.
Only an ultrasound at a vet can determine whether the puppies are too large for normal birth. You’ll need to work closely with a vet to ensure that the female survives the pregnancy and the birth.
Can a Chihuahua Get Pregnant by a Large Dog?
Absolutely. Where there is a will, there is a way – especially when hormones are involved. Usually, the mating is clumsy and not consistently successful. The male can’t always line things up right, which can make mating difficult or even impossible.
However, it can happen – and has in the past.
If you have a Chihuahua, mating opens up a whole can of potential health problems. Chihuahuas should only mate with dogs of a similar size – which often limits their possibilities to other Chihuahuas and toy-sized dogs.
If they mate with larger dogs, they are prone to injury during the mating process and afterward. Their puppies will usually need to be delivered via C-section.
We highly recommend spaying or neutering your Chihuahua if you aren’t a breeder. It’s the only sure way to prevent potentially fatal health problems from cropping up after accidental mating.
Tiny dogs can become pregnant by giant dogs if they are left unsupervised while the female is ovulating. However, that doesn’t always mean it is possible! Often, the mating process is a bit more complicated and clumsier.
When paired with much larger dogs, the female can be injured during many parts of the process. The act of mating can cause physical injury to the female’s genitals and spine. Sometimes, severe injury and even death can occur. After the dogs lock, the male can drag the female around and seriously injure her.
The pregnancy is likely to be hard on the female. The fetuses can grow too large to fit through the birthing canal. In these cases, a C-section will be necessary.
In the end, it is never good to be a pregnant female in these situations.
Featured Image Credit: Tamara Bellis, Unsplash