Q: My rat has a swollen stomach. She is 1 1/2 years old and is in a large cage with another female. Her stomach is at least two or three times larger than normal. The swelling is on the inside, not on the outside like a tumor. A few days ago she ate a praying mantis, and both rats have been eating bread crust. The other female appears to be just fine. Their cage is lined with pine shavings and pellets. Can you suggest what might be the issue?
A: The cause of what you describe could be many things. More likely than not, it is not your rat’s stomach that is swollen but her abdomen. There are many things that could cause a rat’s abdomen to swell.
A large stomach could cause a rat’s abdomen to swell, but that is very unlikely. A mass in a rat’s abdomen could easily cause the abdomen to get larger. A mass could be cancer or an abscess; and the cancer could as easily be benign as it could be malignant.
Enlargement of an organ, such as the liver or spleen, could also cause a rat’s abdomen to swell. These organs can enlarge due to an abscess, cancer or some other disease.
Fluid build-up in the abdomen could also cause swelling. Fluid build-up can be from heart, liver or kidney disease.
Finally, something as simple as fat can cause the swollen look you describe. You may just have an obese rat that is gaining weight, and it is manifested by fat build-up in the abdomen.