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Pet Rats/Sudden death of rat



I am hoping you can help shed some light on the sudden death of my pet rat. I had two male rats that are around 16 weeks old, today I found one of them dead in the cage. I am really upset by this as this morning he was running around the cage as usual.

About a week ago I noticed some white spots on his ears that have gradually scabbed over and a few white spots on his tail. His nose also looks just a little bit bloody.

What do you think was the cause? My other rat has no symptoms at all. I feel very sad for the one left behind.

Can you give any advice on whether it is possible to get another one.

Thank you


Hi Charlotte,
I'm so sorry for your loss. The sudden death of a young rat is most commonly caused by a sudden severe bacterial infection. Sometimes it comes on so quickly you don't have time to notice symptoms. Other less common causes are a stroke, a blood clot in the lung or sudden heart failure due to an abnormal heart. I also recently lost a 20-month-old male suddenly from a tumor inside his heart. Although tumors are more common in older rats, they can occur at any age. An autopsy can sometimes determine the cause of death, but not always. A stroke in the brain would be difficult to detect.

I'm not sure what the white spots on his ears and tail would have been.

Rats have a red pigment in their tears called porphyrin.  This red discharge is a brownish red color and is frequently mistaken for blood.  When their eyes water, the porphyrin can become caked around the eyes, or as the tears run down into their nose it can come out their nose.  It can also get caked on their hands, and spread onto their fur and ears as they groom themselves.  It can be easily removed from the fur with hydrogen peroxide, but just use plain water around the eyes.  When they sneeze, it can make tiny red spots in their cage. If it's just a little, it usually isn't anything to worry about, although if it's a lot or occurs frequently in both eyes it could be a symptom of a respiratory infection or some other problem.  Stress or eye irritation can also cause their eyes to run.

I recommend all rat owners have the antibiotic amoxicillin on hand to give at the first sign something might be wrong with a rat to treat severe secondary bacterial infections. You can read more about that on my website at in the Respiratory Disease article.

Yes, you can certainly get another cagemate for your remaining rat. See the article about how to do introductions.

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Debbie Ducommun


I can answer any questions about pet rats, but you will probably be able find answers to simple questions more quickly on my website at If you have a life-threatening emergency you can try calling me at 530-899-0605. I am not usually on the computer on the weekend.


I have been "The Rat Lady" since 1985 and am recognized as one of the world's experts on pet rats. I have 3 published books and already answer lots of questions about rats daily.

President of Rat Assistance & Teaching Society

I am a monthly columnist for Pet Business magazine, and my writing has appeared in other magazines. I have 3 published books.

BA in Animal Behavior

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