DEAR JOAN: I have an opossum problem, cute bugger that he is. He moves along the fence at night and parks in the foliage. My dog, Penny, goes nuts. Most of the time I can't see him unless my flashlight catches his eyes, but Penny's nose knows. I use the garden hose and he moves along, but the stress on her and me is mounting up.

Suggestions? Fish and Game department? Poison is not an option.

I know that he lives elsewhere because there is no place in my condominium complex for him.

Mary Anne Fifield

San Jose

DEAR MARY ANNE: Ah, the wily opossum. Like raccoons, skunks, squirrels and rats, they often venture into our backyards and upset our balance.

The good news, other than it is giving Penny fits, the opossum is about the least worrisome of wildlife intruders. They can cause some damage -- they are omnivores so there is little they won't eat, including fruits, plants, insects, snails, snakes and frogs. However, they are pretty mellow and aggressive only when confronted which, depending on Penny's size, could be a problem.

Opossums have very strong hands and tiny sharp teeth. Penny would be best served by staying clear. We've had a very large opossum visiting our yard of late, and between the opossum and the cat that sunbathes right outside our kitchen window, my Chihuahua is about to bark himself into a coma.

The reasons the opossum is coming into your yard could be threefold. It may be looking for food and water, your yard may provide a convenient thruway between its den and a neighbor's backyard buffet, or it could be looking for love. The mating season for opossums is January through July.

Look around your yard and the surrounding area to see if you can find its den. In urban areas, they may build a home beneath patios, under steps and in brushy areas. If you find it beneath a deck or porch, wait until it leaves -- and make sure there are no babies -- then block all the entrances.

By removing denning areas, you may convince the opossum to go elsewhere. Removing the food source will help, too. If you leave food and water out for Penny, bring it inside in the evening. Make sure your garbage is tightly closed, and ask your neighbors to do the same.

If there is a way to block the access to your fence, you can try that, but opossums are pretty good climbers. A last resort sort of thing might be to get an electric shock wire. It won't hurt the animal, but it will give it a strong shock.

State law allows you to trap, but that also would mean killing it, which I'm glad to hear isn't an option for you anyway.

DEAR JOAN: I was wondering if you have ever seen black squirrels.

We were at Stanford Hospital and they were all over the place. I have lived in California all of my life and have never seen or heard of black squirrels.

David Hallstone

Brentwood

DEAR DAVID: Stanford and Palo Alto seem to have more than their fair share of black squirrels, which has led to all sorts of urban myths about crazy squirrel experiments.

The black squirrel is just the result of a genetic quirk -- a melanistic mutation -- in gray squirrels. Squirrels with two mutant genes will be black.

Contact Joan Morris at jmorris@bayareanewsgroup.com. Read the Animal Life blog at blogs.mercurynews.com/pets.