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Why does my dog have two sets of testicles?

You are petting your pooch’s belly when you notice something strange. They seem to have more than one set of testes. Instead of one testes on each side, you see two. This gives them a total of four testicles. You scratch your head, confused and concerned. Can dogs have extra testicles? 

Why does my dog have two sets of testicles?

It’s highly unlikely that your dog has two sets of testicles. It can happen, more on that soon, but it’s extremely rare. What is common, however, is the appearance of four testicles. 

This can be caused by health issues, or their natural body processes. 

Bulbus Glandis

You may be aware that when dogs breed, they get “tied” or stuck together. This occurs because of the male’s bulbus glandis. The bulbus glandis is an organ at the base of the penis. When he mates  with a female, or gets very sexually excited, it swells with blood. This causes the penis to get stuck inside the female if he’s mating. 

The gland is found on both sides of the penis base. So, when it swells, it can look like an extra set of testicles. This is nothing to worry about, it’s just how your male’s anatomy works.  

If this is the cause, the “extra set” should disappear when he isn’t sexually excited. It can take about an hour after excitement or mating for them to go back to normal. 

It’s also possible for them to develop an infection in bublus glandis. In this case, the bulb will swell. Pain, redness, and heat are signs that they may have an infection. They may experience pain when urinating or getting an erection. These symptoms need to be evaluated by your vet. 

Lymph Nodes

Lymph nodes can also be mistaken for extra testicles. Dogs have lymph nodes, just like humans. You have probably had a doctor feel the lymph nodes in your neck when you weren’t feeling well.

Just like us, there are a set of lymph nodes near the groin area. 

Lymph nodes are usually small and hard to notice. However, fi your pooch has an infection or other illness, the testicles will swell. The lymph nodes help cleanse the blood and remove infection. When your dog is sick, the strain on the lymph nodes cause them to swell. They can then feel like extra testicles.


You may be surprised to find this one on the list. Male dogs, just like human males, have nipples. This occurs because nipples are developed before gender specific development begins. Both males and females develop the same initially, then they branch off based on their gender. 

Nipples can appear in the groin area, where they can be mistaken for testicles.  

Tricky Testicles 

We often envision the testicles as small round balls. They are irregularly shaped. This can cause one testicle to feel like two separate testicles, leading to the conclusion they have four instead of two.  

Testicle Diseases

So your dog’s regular anatomy and bodily function can make them appear to have extra testicles. However, there are also diseases and conditions that can cause the phenomena. 

One of these is testicle disease. The testicles can become infected just as other organs can. This causes them to swell and become painful. The swelling can cause it to look like there are two sets. Fever and lethargy are also common with infection. 

Another potential cause is testicle torsion. It’s a rare occurrence, but can be a serious condition. The testicles cord gets twisted. This blocks the flow of blood. This causes lots of pain and swelling.  


You may think of ticks as tiny creatures, but some can be much larger than the common small ticks. These are known as dog ticks. If one latches onto your dog’s groin, it will feed and swell with your dog’s blood. This can cause it to seem like an extra testicle.  


Cysts can also give your pooch the appearance of extra testicles. Cysts are fluid filled sacs. They are typically soft. This causes them to appear like testicles. 

They are typically formed underneath the skin due to oil glands getting clogged. As the gland fills, it creates a cyst. These can occur anywhere on the body, including the groin area. 

Abcesses are very similar to cysts. However, an abscess is caused by an infection. They are typically caused when the skin is broken due to a  bite, scratch, cut, or other injury. 

If your pooch gets a wound in their groin area, it could develop into an abscess. 

Abcesses are typically lanced and allowed to drain. Antibiotics and antinflamatory medications may be needed as follow up treatment. 


The last and most concerning cause of your dog appearing to have four testicles is cancer. These can occur in the testicles, penis, or groin. Cancer in any of these areas can look like extra testicles. 

Veneral tumors are another potential culprit. These tumors are transmitted through sexual contact. So, if your dog is old enough to breed, this is a possibility. 

Lymphoma is another possibility. As mentioned  previously, swollen lymph nodes can also be mistaken for testicles. Any type of cancer can cause swollen lymph nodes, but lymphoma begins in them.

This can cause large lumps under the skin, which can appear to be testicles. Other signs of lymphoma include fever, unexplained weight loss, and lethargy.  

Lymphoma must be treated aggressively if your pooch has a chance of survival. Surgery, radiation, and chemotherapy may be needed. 

Can male dogs have 2 sets of testicles?

If your dog seems to have two sets of testicles, you can safely assume that they aren’t actually sporting another set. Instead, it’s likely one of the causes above. 

However, there are rare cases where a dog has more than two testicles. This usually presents as three testicles, with the extra testical appearing on the left side.  However, it is possible to have two full sets of testicles as well. 

The technical term for it is polyorchidism. It’s thought it occurs due to an embryological developmental abnormality, but the full cause still isn’t clear.  

What does 2 sets of testicles mean in dogs?

What it means will depend on whether or not your dog has two sets of testicles, or if it simply appears that they do. 

Mistaken Identity

In most cases, two sets of testicles is just the bulbus glandus. It simply means that your dog got sexually excited, and the swelling should subside within an hour or so. 

If you consistently see what appears to be two sets of testicles, this can be a sign of a problem. If they are there all the time, and not only when your dog is excited, you need to take them to the vet. 

Cancer, cysts, swollen lymph nodes, and other medical causes are much more likely than them having four testicles. This makes it very important for them to get a checkup. 

More Than Two Testicles (polyorchidism)

If your dog actually has more than two testicles, it means they are certainly special. It’s a very rare condition. The testes are usually not problematic. 

However, dogs with the condition are at a higher risk of testicular torsion and malignancy. Your vet may recommend removing the testes, or monitoring them for problems with regular checkups.