A necropsy is a veterinary dissection of a deceased animal. If you would like to have this done, call your veterinarian. After the necropsy, the veterinarian should have more information for you about what was going on inside your gerbil before he died, and a definitive conclusion or a hypothesis about the cause of death. Knowing the cause of death may help comfort you. If the gerbil was having diarrhea before he died, it's important to know the cause of the diarrhea for the protection of the health of any other gerbils you own.
Types of Necropsy
There are two general types of necropsy: a gross necropsy and a necropsy with a full histopathology.
In a gross necropsy, a gerbil gets an external exam and an internal exam. The internal exam looks at various internal structures: the digestive system, organs such as the heart, lungs, liver and kidneys, and notes anything else that presents itself. A gross necropsy is often enough to make a conclusion about the cause of death. If you would like the gerbil's body returned to you, let your veterinarian know. They will wrap the body up before giving him back to you, and it may be best to bury him without looking inside.
In a full necropsy, the internal organs will also be dissected, and specimens may be analyzed for histopathology, microbiology, or serology. Your veterinarian should be able to tell you how thorough this necropsy will be. A full necropsy costs more than a gross necropsy, and it can take a week or two to get results back. They will probably not return the gerbil's body.
Time is of the Essence
After death, the gerbil's body will start degrading. Every hour is important. Ideally, get in the car right away and take him in. Call your veterinarian's office to let them know you are coming.
Preserving the Body
Inevitably, it seems, gerbils will pass away on the weekend when the vet's office is closed. The clock is still ticking, though.
If you have instructions from your veterinarian that are different from the advice below, please follow your vet's instructions.
The gerbil's body must reach the vet within 48 hours. For the most accurate necropsy results, sooner is better. The body has started degrading, and will continue to degrade.
Place the body in a ziploc bag. Do not wrap it in paper or anything else before putting it in the bag. If you wish to conceal it from view, you may put the ziploc bag inside another bag or a box, but there should be nothing between the gerbil and the ziploc bag. Then put the ziploc bag containing the body into the refrigerator. Do not put it in the freezer; freezing will destroy tissue.