They actually do that? I guess it is no more worse than some of the other crap they do . . . literally.
I was being facetious, but I expect if you can imagine it, someone there does it.
For example, sticking stuff where it doesn’t belong.
From The Straight Dope:
http://www.straightdope.com/columns/read/478/is-it-true-what-they-say-about-gerbils
Brace yourself, toots. What follows isn’t for the weak of stomach. For starters, an awful lot of stuff has been found where that gerbil was found. The medical journals list, among other things, the following astonishing array: A bottle of Mrs. Butterworth’s syrup, an ax handle, a nine-inch zucchini, countless dildoes and vibrators including one 14-inch model complete with two D-cell batteries, a plastic spatula, a 9-1/2-inch water bottle, a deodorant bottle, a Coke bottle, a large bottle cap, numerous other bottles, a 3-1/2-inch Japanese glass float ball, an 11-inch carrot, an antenna rod, a 150-watt light bulb, a 100-watt frosted bulb, a cucumber, a screwdriver, four rubber balls, 72-1/2 jeweler’s saws (all from one patient, but not all at the same time, although 29 were discovered on one occasion), a paperweight, an apple, an onion, a plastic toothbrush package, two bananas, a frozen pig’s tail (it got stuck when it thawed), a ten-inch length of broomstick, an 18-inch umbrella handle and central rod, a plantain encased in a condom, two Vaseline jars, a whiskey bottle with a cord attached, a teacup, an oil can, a six-by-five-inch tool box weighing 22 ounces, a six-inch stone weighing two pounds (in the latter two cases the patients died due to intestinal obstruction), a baby powder can, a test tube, a ball-point pen, a peanut butter jar, candles, baseballs, a sand-filled bicycle inner tube, sewing needles, a flashlight, a half-filled tobacco pouch, a turnip, a pair of eyeglasses, a hard-boiled egg, a carborundum grindstone (with handle), a suitcase key, a syringe, a file, tumblers and glasses, a polyethylene waste trap from the U-bend of a sink, and much, much more. In 1955 one man who was “feeling depressed” reportedly inserted a six-inch paper tube into his rectum, dropped in a lighted firecracker, and blew a hole in his anterior rectal wall. This changed his mood real quick.
Which brings us to gerbils. While the examples above are well-documented in the medical literature, live or recently deceased fauna are something else. Rumors of gerbil (and mouse or hamster) stuffing have been circulating since about 1982. In 1984, a Denver weekly said it had a confirmed report of gerbilectomy in a local emergency room. The Manhattan publication New York Talk reported several years ago that New York doctors first caught on to stuffing when they started encountering patients with infections previously found only in rodents. But no such case has ever found its way into the formal literature of medicine.