Q: My 7-year-old son is dying for a dog. That's out, because I'm not really a dog person. I've also ruled out lizards and snakes. My husband is allergic to cats, so that's out, too. We're down to either a rabbit or a guinea pig. Pros and cons?

A: I tend to prefer recommending guinea pigs for younger children, because rabbits can be surprisingly fragile. If a rabbit is held insecurely and kicks out in fear, he can break his back -- a sad ending for both the child and the animal.

Guinea pigs are better designed to be a child's pet. They're smaller than most rabbits, rounder, have shorter legs and are easier to hold than even dwarf rabbits. If your son is gentle enough to learn to handle a pet carefully, though, either pet will do. You might volunteer to provide vacation care for a rabbit or guinea pig owned by one of your son's friends first, just to be sure the animal isn't an allergy trigger for your husband.

Both rabbits and guinea pigs are a lot more interesting than most people realize. Throw them in a tiny cage or hutch with nothing to do, and they'll just shut down. But set them up with a little room to roam inside the house (canine exercise pens made of plastic or metal make great enclosures), with toys for playing and chewing, and they'll come alive.

Many guinea pigs and rabbits will readily adapt to using a potty box filled with an inch or so of pressed paper or wood pellets that's been topped with fresh grass hay. These pets can serve as efficient and enthusiastic recyclers of vegetable scraps from your kitchen, and they will turn them into waste products that will supercharge your compost pile. (You don't scoop the box -- you just replace the contents regularly, as everything in the box is compostable.)

I prefer to not feed my rabbits a pelleted food. Instead, I offer them all the fresh grass hay they want along with twice-daily offerings of fresh greens -- collard, mustard and so on -- plus broccoli and other vegetables and treats of apple slices. Guinea pigs are not able to produce their own vitamin C, however, and so must have a commercial pellet formulated just for them as a base for their diet.

VeterinaryPartner.com has excellent articles on caring for all small pets, written by Dr. Susan Brown, who's known for her work with these animals.

A final bit of advice: Although longhaired rabbits and guinea pigs are gorgeous, the amount of maintenance those coats require make them highly impractical as a child's pet.

Do you have a pet question? Send it to petconnection@gmail.com.