Q. I was wandering around a pet supply store the other day and my eye caught on flea combs, of all things! But I noticed some with narrow-spaced teeth for use on dogs. Will these combs really get rid of the fleas that live on my dog, Zvi?

A. Nope. Combing out adult fleas on Zvi has no effect. There are, literally, thousands of immature stages of the flea's life cycle living on your dog and in his environment. The safest, most effective flea control products are the new generation, sold -- you guessed it -- only by your vet!

Q. Merrie's getting on in years. What are the usual signs of aging that I should be aware of? I'd like to be able to quickly take care of any problems she might develop, and provide her with what she needs to get through her senior years easily.

A. Merrie's lucky to have you. Some of the things to look for are a greater intolerance of heat, cold or change in her life, loss of strength, and, as organ function deteriorates, a greater susceptibility to disease. Go to your vet at the onset of problems to minimize their effects. And have her checked once or twice a year.

Q. What causes deafness in dogs? Hank's not responding to noise the way he should. We're thinking of having his hearing evaluated.

A. Hearing loss is very often traced to congenital deafness (a birth defect in which sound-receptor cells in the ear fail to form), a severe ear infection that destroyed the bone and tissue that conduct sound or the neural receptor cells, or a toxic reaction to ear drugs. So, yes, take Hank to the vet.

Q. Melvin's getting kinda chunky. I know obesity's a major health threat to dogs, as it is with humans. But, at what point should we consider Melvin obese?

A. Tsk-tsk-tsk. Poor Melvin. You really should take better care of him. In any case, the general rule states that a dog weighing 20% more than the ideal weight for his age, sex and breed is considered overweight. Your vet can help you determine what Melvin's ideal weight is, and can suggest a dietary and exercise plan. Calorie counting -- and restriction -- is the key.

Q. Our dog training book suggests growling at your dog, or even biting him in order to stop his aggressive behavior. We'd never heard of such a thing! Is this a good idea? I'd sure hate to have Jazz turn around and bite me back!

A. Truer words! You could very well end up being bitten yourself -- especially if Jazz is an older puppy or an adult. I wouldn't try it, if I were you! (Who on earth would recommend such a thing?) Contact your veterinarian. He or she can help you with behavioral problems or direct you to an obedience trainer or a behavioral specialist.

Q. We're at our wits end. Snooze is a nuisance barker. We correct him during these barking fits, but it doesn't help. What causes this?

A. The biggest culprits are boredom, guarding his territory, and separation anxiety. Some breeds are more hyper and so they bark. Look for what triggers the barking and when and why he barks. Then go to your vet for advice because each cause or type of barking requires a different strategy to correct. Citronella-spray collars are often quite effective, and very humane.

Q. When's the best time to demat Fred -- before or after we bathe him? Also how do dematting products that you apply directly onto the mats, work?

A. Brush and demat Fred before you bathe him. If you don't, once the mats are wet, you may have to cut them out to get rid of them -- not a fun project. Dematting products are applied to and worked into the mats and are supposed to make the hair slippery and, therefore, easy to untangle.

Dr. Whaddowedo is our column for information from the American Veterinary Medical Association.