Dogs are built a little differently to humans – with four legs and a tail, it should already be obvious! However, looking down below, you will see some things are even stranger. If you’ve ever noticed that your puppy sometimes appears to have multiple testicles, today’s article is for you. Can dogs ever have more than two testicles? If not, what are you seeing?
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Normal Anatomy
A dog’s anatomy is similar to that of a human in many ways, but there are some key differences, which can easily mislead the unsuspecting owner!
The Bulbus Glandis
One of the most significant is the presence of the bulbus glandis (also known as the bulb or knot) found at the base of the penis in male dogs. During mating, the male bulbus glandis swells inside the vagina of the female. Her vaginal muscles will contract around the bulbus glandis, ‘locking’ the penis inside. The male dog will then dismount the female, turn 180° so they are facing away from each other – the bulbus glandis ensures the male remains inside the female until coitus is complete. This is why dogs will remain ‘stuck together’ after mating. You should never forcibly remove them as you can damage either animal – remember the tie can last up to an hour.
We believe the bulbus glandis is what most people see when they notice ‘extra testicles’. When a dog is aroused, the bulb swells. Because it is located either side of the penis, it often looks like two little round lumps under the skin. In some cases, the penis sheath will retract and the bulbus glandis will become even more visible. Enlargement of the bulbus glandis can occur in young dogs and even neutered males. Erections can last an hour or more, but the bulbus glandis tends to reduce in size after the event. It shouldn’t be a painful process.
There can uncommonly be problems with the bulbus glandis, mainly inflammation or infection in the region. This may cause the bulb to swell, become hot and painful, and possibly lead to painful urination, painful erections or even blood in the semen or urine. If any of these signs are present, speak to your vet
Normal Testicle Anatomy
The other potential source of the ‘four testicles’ misconception may be related to the testicles themselves. The testicles are not perfectly round spheres but rather irregular. This irregularity can sometimes feel like multiple smaller lumps inside the scrotum, which can be confused with extra testicles. The anatomy of the testicles starts with the large oval testes, where sperm is produced. Above and below this is the epididymis, responsible for storing sperm and producing components of semen. The head and body of the epididymis are rather prominent at either end of the testis, and thus can sometimes be felt as distinct lumps – these can be confused for extra testicles.
Other Structures
There are some other structures in the groin region that might be confused for extra testicles. In the groin, dogs have lymph nodes – these are responsible for draining away fluid from the legs and fighting infection. Normally, they are difficult to feel, but when enlarged they can become prominent. Lymph nodes can become enlarged due to nearby inflammation or infection, as well as generalised unwellness. Cancers are rare in puppies, but they do occur and can cause lymph node swelling too.
It is also important to remember that, just like male humans, male dogs have nipples too. These can sometimes be quite prominent and can be found anywhere in the groin, even along the penis itself. It is not unheard of for these to be confused with cysts, ticks, skin tags or cancer, as well as extra testicles!
Abnormalities
Not all things confused with testicles are normal – some diseases can sometimes be mistaken for suddenly-appearing testicles.
Testicular Disease:
All the structures of the testicles can become inflamed or infected. These conditions can be quite painful and may lead to blood in the sperm, a high temperature, pain when urinating or aroused, and other symptoms. Depending on the cause, we may treat it with anti-inflammatories or antibiotics
Testicular torsion is a condition where the testicular cord that holds the testicles in the scrotum twists and gets blocked. This results in a blocked blood supply to the testicles, causing swelling and intense pain. We normally have to treat this with castration. It is rare to occur in normal testicles, but is more common in retained cryptorchid testicles.
Cancers of the testicles are also possible. They are very uncommon in puppies, but should be a consideration for older intact males. The most common are Leydig cell tumours, Sertoli cell tumours, and seminomas – these are all cancers of specific cells of the testicles. Thankfully, most are benign and can be treated with castration. Once again, they are rare in puppies, but are more common in retained testicles.
Skin Disease:
Skin disease in the groin region can just as easily be confused with an extra testicle or two. Any sort of disease can result in inflammation, though some may be more obvious than others.
Cysts are pockets of fluid. They are often raised and rounded, and feel quite soft. The fluid inside can be watery, or thick and pus-like. Cysts most commonly form when sebaceous glands in the skin get blocked and start to fill up. Cysts can appear suddenly and it is easy to see how they could be confused with testicles. Treatment may involve antibiotics, anti-inflammatories or drainage, but often surgical removal is most effective.
Abscesses are similar to cysts, but contain pockets of infection. They can occur due to bites (especially from a cat!), a foreign body, an infected wound and more. Accident-prone puppies could easily get abscesses forming in their groin that can become quite large and painful. To treat, we first want to lance and flush the abscess clean, to remove any infection. Aftercare may then involve anti-inflammatories or antibiotics again.
Ticks are nasty little parasites that burrow into the skin to drink the blood of animals. They are commonly found in thick grassy areas in certain parts of the country, so young puppies that love the great outdoors are at the biggest risk. As they drink, their bodies swell with blood and look like little round lumps. If your puppy is unlucky enough to get one in their groin, it may be confused for a testicle! Looking closely, however, you may spot wriggling legs! Removal is important, as there are a number of dangerous diseases transmitted by ticks. You can do this yourself with a tick-removal device, or see a vet. Luckily, preventing ticks is easy with monthly medication.
Cancer:
As with testicular cancers, cancers in the groin or on the penis can look rather alarming, and possibly be confused for something else.
Transmissible venereal tumours are a kind of tumour that can be spread by sexual reproduction between dogs. It tends to be malignant, sometimes spreading to other parts of the body and causing damage. Treatment involves removing the cancer and infected organ, and potentially chemotherapy or radiotherapy. As they are most commonly spread via copulation, they are unlikely to occur in puppies, and more common in breeding dogs.
Lymphoma is another form of cancer that can occur almost anywhere in the body, particularly the skin where it can form masses that could be confused for testicles. Unfortunately, unlike most cancers, lymphoma can occur more frequently in puppies, so it is possible for these to be seen in young puppies. Treatment can be difficult and depends on the type of lymphoma. It may involve surgery, chemotherapy, radiotherapy or steroids. Lymphoma unfortunately tends to spread to other parts of the body and cause other issues.
Remember, however, that cancers in puppies are still very rare, so are unlikely to be confused with testicles in a young dog.
Four Testicles
Okay, we fibbed a little. It is theoretically possible for a dog to have more than two testicles. This is termed polyorchidism and is a congenital disease an animal can be born with. However, it is exceedingly rare, with only around 200 cases reported in humans, and only two seen in dogs. One dog in particular had a third retained testicle, so still had two normal testicle in the scrotum – it was only identified after he was castrated normally. So while not technically impossible, it is far more likely your dog’s extra testicles are something else. So we still feel that in almost all cases it is the normal bulbus glandis that has been identified. Therefore, try not to panic next time you spot some extra balls on your young puppy! And as always, if you are ever unsure, please speak to your vet.
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