Does My Male Dog Have 4 Balls?

Anatomy of the Male Dog

The primary reproductive organs of the male dog are the testicles and scrotum. The testicles, also called testes, are oval organs that produce sperm and the male sex hormone testosterone. Most male dogs have two testicles located in an external sac called the scrotum. The scrotum is a pouch of skin that keeps the testicles at an optimal temperature for sperm production, which is slightly below normal body temperature.

Each testicle is enclosed in a fibrous capsule called the tunica albuginea. Inside the testicle, sperm are produced in structures called seminiferous tubules. The sperm mature as they pass through the epididymis, a tightly coiled duct attached to the top of each testicle. During ejaculation, sperm travel from the epididymis through the vas deferens to the urethra, and then out of the penis.

The testicles develop inside the abdomen and normally descend into the scrotum before birth. This descent is critical because the lower temperature of the scrotum is necessary for normal sperm development.



Male dogs typically have two testicles descended by 6 months old located in a sac called the scrotum. The testicles produce testosterone and sperm. Most male dogs have two testicles descended into the scrotal sac by the age of 6 months, although giant breeds can take slightly longer. If a dog has undescended testicles after 6 months, this is called cryptorchidism.

According to veterinarians, it is possible but very rare for a dog to have more than two testicles. This condition is called polyorchidism and is present from birth (congenital). Extra testicles are often smaller, underdeveloped, and nonfunctional. While theoretically possible, verified cases of dogs with more than two fully formed, functional testicles are extremely rare in veterinary medicine.


Cryptorchidism is a condition where one or both of a male dog’s testicles do not descend into the scrotal sac. This means the testicle either remains in the abdomen or becomes stuck somewhere along the path of descent. Cryptorchidism is common in dogs, occurring in up to 10% of male dogs (VCA Hospitals).

During normal development, a male dog’s testicles descend into the scrotum by 2 months of age. If this does not occur by 4 months of age, it is unlikely the retained testicle(s) will descend on its own (PetMD). Cryptorchidism can affect one testicle (unilateral) or both testicles (bilateral).

The underlying cause is unknown but may be related to abnormalities in hormones or nerves controlling testicular descent. Certain breeds like Pomeranians, Chihuahuas, and Boxers are predisposed. Complications like testicular cancer or testicular torsion are more likely if cryptorchidism is left untreated.

Development of Testicles

Testicles start developing near the kidneys while puppies are still in the womb. Usually by 2 months of age, the testicles descend into the scrotum through the inguinal canal [1]. The descending typically happens between 6-16 weeks old [2]. However, it can occur later in some breeds.

The testicles descend at different times, with one testicle usually descending 1-2 weeks before the other. By 6 months old, most puppies will have both testicles fully descended into the scrotum.

Four Testicles?

It is extremely rare for a male dog to actually have four testicles. While some owners may think their dog has four testicles, this is usually not the case. What owners are observing is a normal anatomical structure called the bulbus glandis.

The bulbus glandis is an enlargement of erectile tissue located at the base of the penis, in front of the scrotum. When a male dog is aroused, the bulbus glandis swells up and can look similar to testicles. However, this is a normal part of a dog’s anatomy and not an indication that the dog actually has four testicles.

True polyorchidism, or the condition of having extra testicles, is possible but very uncommon in dogs. If a dog did have an extra set of testicles, this would likely indicate an underlying developmental abnormality or medical condition that should be evaluated by a veterinarian.

Some potential causes could include:

  • Failure of the embryonic testicles to fuse properly
  • Duplication of the genital ridge during embryonic development
  • Abnormal stimulation of the gonads by hormones

While curiosity about a dog’s anatomy is understandable, true polyorchidism in dogs is extremely rare. If a dog appears to have four testicles, it is most likely the normal bulbus glandis structure. However, any concerns about abnormalities should be discussed with a veterinarian.

Causes of Extra Testicles

In rare cases, a male dog may appear to have an extra testicle. However, this is often not an actual testicle, but rather another growth near the scrotum. The most common causes of growths that could be mistaken for an extra testicle include:

Tumors: Testicular tumors are uncommon in dogs, but can occur. Tumors may arise from the testicle itself, the epididymis, or the spermatic cord. Testicular tumors will cause swelling and abnormal enlargement of the testicle. While rare, testicular tumors are most common in older dogs. [1]

Cysts: Cysts can develop in the testicles, epididymis or spermatic cord. These fluid-filled sacs may enlarge the scrotum and appear like an extra testicle. Cysts often develop due to inflammation, infection or trauma in the testicles. [2]

Testicular hypoplasia: This congenital condition results in an underdeveloped, small and nonfunctional testicle. The abnormal small testicle may be mistaken for a third or fourth testicle if only one testicle has descended properly into the scrotum. However, the hypoplastic testicle will be smaller and abnormally shaped compared to normal testicles. [3]


The diagnosis of extra testicles in male dogs begins with a physical exam by a veterinarian. The veterinarian will palpate the scrotum to feel for any abnormal masses or testicles. According to VCA Hospitals, the veterinarian will look for asymmetry of the scrotum and palpate the inguinal canals and abdominal area for undescended testicles.

If an undescended or extra testicle is suspected, imaging tests may be recommended. Radiographs (x-rays) or an abdominal ultrasound can help locate retained testicles. However, these imaging tests are not always necessary before surgical exploration and removal. The physical exam is usually sufficient for diagnosis in straightforward cases.


If a male dog is found to have extra testicles, the recommended treatment is surgical removal. The surgery to remove the extra testicles is called a cryptorchidectomy and is commonly done at the time of neutering. This allows the veterinarian to fully examine and remove all testicular tissue while the dog is under anesthesia.

According to veterinary experts, removal of the extra testicles provides the following benefits:

  • Eliminates the risk of testicular cancer, which is increased when cryptorchidism is present.
  • Prevents discomfort or testicular torsion caused by the presence of extra testicles.
  • Allows for full examination to confirm no testicular abnormalities or masses are present.

In rare cases, hormone therapy may be recommended prior to surgery to lower testosterone levels and encourage the extra testicles to descend. However, surgical removal remains the standard and most effective treatment.

Overall, prompt surgical removal of any undescended or extra testicles provides health benefits and avoids complications in affected male dogs. It is considered safer and more definitive than watchful waiting or hormone therapy alone.


The prognosis for dogs with an extra set of testicles is generally good with early treatment. Surgical removal of the extra testicles is usually curative. However, some complications can arise that require monitoring.

According to the Animals Surgical Center, the prognosis for testicular tumors that have spread is more guarded, but varies greatly depending on the location, type of tumor, and treatment options. With early surgical removal of the tumor, most dogs can be cured. However, if the cancer has already spread at the time of diagnosis, radiation therapy or chemotherapy may be necessary.[1]

After surgery to remove the extra testicles, dogs should be monitored for potential complications like infection, swelling, or fluid buildup. Owners should watch for signs like excessive licking, redness, heat, discharge or swelling in the surgery area and alert the veterinarian if these occur. With prompt treatment of any complications, most dogs recover fully after removal of extra testicles.

Overall, by having the condition addressed early, remaining vigilant about potential complications post-surgery, and following the veterinarian’s recommendations, dogs with an extra set or testicles can go on to live a normal, healthy life after treatment.

When to See a Vet

If you notice any abnormal development or symptoms in your puppy or dog’s testicles, it’s important to schedule a veterinary exam right away. Some signs that warrant an urgent vet visit include:

  • One or both testicles are undescended at 2 months of age
  • The scrotum appears empty or only contains one testicle
  • You feel small, hard masses in the scrotum or inguinal area
  • Your dog is exhibiting signs of abdominal pain or discomfort
  • There are any masses, swelling, or asymmetry of the scrotum or testicles
  • Your pet is having difficulty urinating or defecating

According to veterinarians, early diagnosis and treatment is critical for preventing complications like testicular cancer or infertility in cryptorchid dogs. Therefore, schedule an exam promptly if you have any concerns about your dog’s testicles or scrotum. Your vet will perform a physical exam and may recommend abdominal radiographs or other diagnostic tests to check for retained testicles. They can then advise you on the best treatment options based on your dog’s specific case.

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