Q. What is the difference between a calico and a tortie, or are they the same? Do the terms calico and tortie refer to a breed or a color? C.F., via e-mail
A. Calico and tortoiseshell (or tortie) refer to a pattern of markings, not to a breed. The link between them is orange fur. The two marking patterns are genetically similar, but they differ in the way the orange color is displayed. On calico cats, the orange, black, and white colors are distinct patches; on tortoiseshells, the colors swirl together.
The overwhelming majority of calico and tortoiseshell cats are female. Male calicos are what's known as ''Klinefelter" males, having not only the XY chromosomes but also an extra X. Since you need two X chromosomes to get a calico, you need the XXY combination to get a male calico. It doesn't happen very often -- about 1 in 3,000 calicoes is male. Typically, male orange cats are tabbies (the common striped pattern), while orange in females can be expressed in any of three patterns -- calico, tortoiseshell, or tabby. To make things a little more interesting, there are also ''dilute" colors. Instead of the pure orange and jet black of a classic calico, the orange on a ''dilute" calico is more of a cream color, and the black is gray.
The Cat Fanciers' Association has a basic explanation of feline color genetics on its website at www.fanciers.com.
Q. We have a new golden retriever puppy, and I bought her with plans to make her a running partner. How soon can she accompany me on my daily runs? D.K., via e-mail
A. According to Dr. Robert Richardson, a Sacramento, Calif., veterinarian known for his expertise in orthopedics, you need to wait a while before putting the miles on that pup. Richardson says an 8-month-old dog can safely manage only a one- to two-mile run at a relatively slow pace -- and that's if the animal is perfectly sound.
A puppy who's 8 months old is just past the usual growth spurts, says Richardson, who cautions that before that age, a puppy's cartilage is very soft and easily damaged. If you push your developing pup, or get a dog with joint problems to run at all, you could be risking serious problems down the road. Consult your vet for a precise assessment of your dog's suitability as a running partner.
Q. I have always wanted a pet duck. Do I need to have her wings clipped to keep her home? We have a small pond and a ton of (nonbaited) snails. What do you think? S.W., via e-mail
A. When it comes to bird advice, I always turn to Dr. Brian Speer, my ''Birds for Dummies" co-author. In addition to being past president of the Association of Avian Veterinarians (aav.org) and a popular speaker at veterinary conferences around the world, Speer is one of only a handful of veterinarians certified as avian specialists in both North America and Europe. On his 2-acre ''bird ranch" in the San Francisco Bay Area he has had every kind of bird imaginable, from parrots to emus, quails to turkeys, ostriches to finches.
Speer notes that both clipped and unclipped pet ducks face hazards. By clipping the outer primary flight feathers of most pet ducks, their ability to take off and fly is temporarily removed, he says, noting that feathers do regrow after moulting and would need to be monitored and clipped as needed. The biggest problem: Clipped wings leave ducks grounded and vulnerable to predators.
What would happen if you don't keep wings trimmed? Speer says pet ducks who can fly most likely will fly. And that also has risks: Your ducks may fly into the neighbor's yard where dogs may injure or kill the birds, or your ducks may fly into roadways or onto other equally hazardous landing sites.
''Pet ducks are a source of great enjoyment," says Speer. ''I would recommend a fenced enclosure -- including the top -- that will keep the birds in and predators out. When you're in the yard, the birds could be out, and when you are away, they can remain fenced and protected."
Q. When our cat got sick, our veterinarian recommended giving her human baby food to coax her to eat until she felt better. Is that healthy? O.S., via e-mail
A. Pureed meat in those tiny jars meant for human babies is commonly recommended to help sick cats keep eating. The diet's not meant to be a long-term solution, but rather is an important strategy for keeping a sick cat from getting sicker.
As I'm sure your veterinarian told you, it's important to make sure you're not choosing a variety of baby food with onion powder in it because of the risk the substance poses to your already ill cat. Read the label. Warming up your cat's food will increase its appeal.
It's important when you're nursing a sick pet that you understand your veterinarian's instructions and get all your questions answered. Don't be afraid to call for more information if questions come up after you leave your veterinarian's office.
Gina Spadafori is the author of several pet-care books and a consultant to the Veterinary Information Network. Her Web log and column archives can be found at spadafori.com.