Dear Reggie Rat: My college-aged nephew just bought a pet rat, and I am appalled. I think of rats as vermin that require a trap, not pets that sit on laps. Is it safe and sane for my nephew to keep a pet rat?

Reggie Responds: We domestic rats are wonderful pets. We're smart, sturdy, social animals that get along well with each other and with humans.

You needn't worry about your nephew. Well-socialized pet rats are far less likely to bite than other pocket pets or wild rats that are hand-raised.

Most pet rats enjoy everyone but prefer one particular person in their lives. Research shows that rats will even work to be petted by someone special.

We rats like to doze in pockets or on shoulders. We're easy to train, and we'll do tricks if trained with food treats.

Pet rats are ideal for college students because we don't cost much to keep. A rat needs only a cage with nesting box, toys, tunnel, exercise wheel and water bottle. We eat rat pellets or blocks plus fresh vegetables and fruit.

I predict that you'll be enchanted once you've met your nephew's pet rat.

°°°

Dear Christopher Cat and Daisy Dog: Can cats and dogs mate with each other?

Christopher and Daisy Respond: No. Our anatomy and breeding behaviors are just too different.

However, interspecies breeding does occur in other animals.

For example, there are more than 40 examples of crosses involving different species of wild cats (such as lions and tigers) or domestic and wild cats. The three most common cat breeds produced by crossing a pet cat with a wild cat are the Bengal (crossed with Asian leopard cat), Savannah (with African serval) and Chausie (with jungle cat).

Domestic dogs, wolves and coyotes also breed with each other.

Horses and donkeys interbreed. A mule is a cross between a male donkey and a female horse. A hinny results when a male horse is bred to a female donkey.

Bird breeders cross finches with other species, such as canaries, and the hybrid offspring are called mules.

Amazons, conures and macaws all interbreed. Different species of domestic ducks interbreed, and domestic ducks breed with wild species.

Falconers cross different species of falcons to produce birds with the hybrid vigor that makes them better hunters.

Backyard birds sometimes interbreed. For example, black-cap chickadees breed with Carolina chickadees where their ranges overlap.

Other species that interbreed are whales and dolphins, cattle and buffalo, different species of snakes (such as a boa and a python) and different species of crocodiles.

African killer bees are the product of crossing African bees with honeybees, in an attempt to breed bees that produce abundant honey and can tolerate heat.

Some offspring of interspecies breeding, particularly the males, are infertile. But others can continue to breed and establish a new species.

Ask the Vet's Pets appears Fridays in the print edition of the Reading Eagle. The animal authors of the column live with Lee Pickett, V.M.D., who practices companion animal medicine. Contact them at www.askthevetspets.com.