Dear Dr. Fox:

My husband and I have a 3-year-old neutered cairn terrier, Coby. He loves people, is friendly with other dogs and even likes cats! But he snaps at children. When I take him for walks in our subdivision, should a neighborhood child want to pet him, I have to say "No!" because Coby growls and snaps at them.

Why would an otherwise friendly dog suddenly become aggressive around children? Is it because we have no children of our own?

S.M.F., Alexandria

It's not unusual for dogs raised with adults and having no early contact with children to be wary of them later in life and bare their teeth and even bite -- more often out of fear than purely aggressive intent. Sometimes, dogs who have never seen people of a different culture or race, or have never seen a bearded man might react in the same way.

This "socialization deficiency" can be rectified by gradually exposing your leashed dog at a distance to children in a playground, schoolyard or park, so that he becomes accustomed to their noisiness and boisterousness. Such desensitization, which may take several weeks before he becomes more calm, should be followed by gradually taking him closer to the children, but not, of course, close enough for him to either bite or react fearfully.

Once Coby seems to understand that children do not intend to harm him, if possible, find a family that has a dog and sensible older children, so that (on the leash) Coby can see another dog happily interacting with children. From then on, with food rewards and ultimately the children walking your dog on the leash, he should overcome his socialization deficiency. But take no risks -- one bite injury could have tragic consequences.

Dear Dr. Fox:

During the past two weeks, Oreo, our cat, appeared very disoriented and started walking into walls. We took her to the vet, who told us she is blind! He doesn't know what caused the blindness but said that nothing could be done for her. My husband, my children and I are devastated -- Oreo is an integral part of our family.

What could have caused a healthy cat to become blind almost overnight? Is this common in cats? Would it help to take her to another vet? What can I do to help Oreo?

J.M.C., Palm Beach, Fla.

I sympathize with you. The shock of hearing your veterinarian's diagnosis must have been terrible. Yes, you should take Oreo to another doctor -- not because that veterinarian is necessarily going to help her recover from her blindness (the disease may have progressed too far) but because it's important to find out what caused the condition so that you can keep Oreo well.

A full clinical checkup is advisable. Various health problems, such as diabetes and inflammation of the retina caused by a viral infection or autoimmune disease, can result in visual impairment. (Some causes of blindness, if identified and treated early on, can be nipped in the bud and the cat's vision partially or completely restored.)

Take heart. Blind cats and dogs can adapt extremely well, provided they're handled with care and understanding. And yes, there are a number of things you can do to help Oreo. Most important -- don't move any furniture around in your environment; it could disorient your cat. And place out of reach any object that could be knocked over by Oreo and injure her. Make sure, also, that you have catches on your doors, so that she can't get out if you're not looking.

You might also put up a carpeted "tree" in your home, with resting shelves at various heights. With a little coaxing a blind cat will come to enjoy this. Also, try her on a leash and harness; Oreo may enjoy a stroll or a roll outdoors. And give her a pinch of catnip now and then for a "high."

Blindness must surely cause animals some anxiety at first, but it's remarkable how well they can adjust to it. Just as with humans, a nurturing environment makes all the difference. With your help and love, Oreo can still have a good life ahead of her.

Dear Dr. Fox:

My parakeet, Freddy, has a habit of landing on people and nibbling on their skin. Otherwise, he's very friendly to humans and very social. Why does he do this? How can we stop him?

Also, he's been sick lately, and the vet can't find the cause. Could he be picking up germs from people when he nibbles on them?

K.B., New York

It's very unlikely that Freddy is getting germs from people. There may be some flu-like viruses that could cross the species boundary, but you'd know it if Freddy came down with one of them. By nibbling on people's skin, Freddy is showing affection in the best way he knows. If he was with another bird -- and, please, consider getting him a companion -- he would be expressing this behavior as caregiving social preening, carefully nibbling his buddy's plumage.

Dr. Michael Fox, author of many books on animal care, welfare and rights, is a veterinarian with doctoral degrees in medicine and animal behavior. Write to him, in care of United Feature Syndicate, 200 Madison Ave., New York, N.Y. 10016. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

(c)2002, United Feature Syndicate Inc.