Dear Dr. Fox: Sam, our cat, loves to lick new bananas. Lately, he has also taken to licking photographs and seems to find them everywhere – on counters, shelves, etc. Can this new habit harm him? Are there chemicals in photos that can make Sam sick? – The G.’s

Dear G.’s: You should not allow Sam to lick banana skins or other fruit, nor should you allow him to lick photographs, plastics, etc. Fruit is sprayed with oils, waxes, pesticides, and various other chemicals and agents to prevent spoilage. Photos, films, plastics, etc., contain potentially harmful chemicals and organic compounds, some of which come from “animal tallow.”Tallow is the grease that’s skimmed off from the rendering vats where the discarded and condemned remains of farm animals and road kills are converted into marketable, but potentially hazardous, byproducts. Unfortunately, it can leach out and sometimes contaminate foods wrapped in plastic, so it’s not a good idea to allow your cat to lick photos that may contain it.

If Sam likes bananas, why not unpeel one and give him some? One of my cats likes bananas, although corn on the cab is his ultimate delight.

Dear Dr. Fox: Our 8-year-old dog has been diagnosed with having thyroid trouble. She has lost hair on both of her sides, and her skin has turned coal black. (Fortunately, she’s a black dog, or she would really look weird.) Is this normal with thyroid conditions? And will the hair grow back? – M.B.

Dear M.B.: Thyroid replacement therapy may induce hair to return on the bald patches, where it often begins as a light fuzz. We have yet to discover why the thyroid glands of so many dogs today become dysfunctional.

Dear Dr. Fox: Years ago I obtained and raised some “waltzing mice,” but I haven’t read or heard about this strange breed since. Do you have any information on them? – H.K.

Dear H.K.: “Waltzing mice” used to be a popular curiosity. They are a mutant variety and suffer from an inherited brain abnormality that upsets their balance, especially when they’re very active or disturbed. Their attempts to correct their balance gives the impression that they’re waltzing or making dancing steps. In nature, these creatures would quickly would be eliminated by predators.

I’m opposed to the propagation of physically incapacitated creatures like “waltzing mice” as pets and curiosities.

— The Animal Doctor appears every Monday. Write to Michael Fox, United Features Syndicate, 200 Park Ave., New York, N.Y. 10166.