Looking for a way to keep your dog busy on those days when the cold limits outside activity? It's easy: Exercise his mind.

Veterinarians have long been sounding the alarm on what the lack of exercise is doing to the health of our pets, triggering an obesity crisis that's echoing our own. Regular exercise means pets with fewer health and behavior problems.

But many of our dogs are also getting the short end of the stick when it comes to exercising their minds. And winter is a great time to teach your old dog a few new tricks.

What many people don't realize is that training is a way of communicating with your dog, of sharing a common language. The more words you both know the meaning of, the more you are sharing your lives.

How many words can your dog know? You'd be surprised. Consider that dogs who serve people with disabilities are routinely trained to perform dozens of different tasks. If you say your dog is not as smart as a service dog, we'll argue back that even if he's only half as smart, he can learn a couple of dozen more things than he knows now.

Besides, tricks are great fun for all dogs. While canine whiz kids such as poodles and border collies will pick up things quickly, any dog will catch on eventually, if you're patient, consistent and encouraging. You can teach tricks one at a time or a couple at once, as long as you have time to practice each one several times a day.

Some dogs are better at some tricks than others. A small, agile terrier may find jumping through hoops easier than a bulldog would. And a retriever is probably more willing to hold things in his mouth than is a Pekinese. A basset hound can probably roll over but may find begging a little hard, being a little top-heavy. So think about your dog's form and aptitudes before you start. You may notice something special your dog does that would be entertaining if you can get him to do it on command. You can. Give it a name, use that word when he's most likely to do his thing, and praise him for "obeying." He'll make the connection soon enough.

You can dress up tricks a little, too, to make them seem more than they are. We've both judged at events with prizes for pet tricks -- always a fun way to spend an afternoon. At one such event, the winner was a friendly Rottweiler who liked to jump in the air after soap bubbles. The trick itself wasn't that big a deal, really, except for the fact that the owner turned it into a crowd-pleaser with a few props.

She put a ballerina skirt around the dog's middle, with matching pink leg warmers on her back legs and a tiara on her head. She then put on "Swan Lake" in her portable stereo and starting blowing bubbles. The dog's leaps and turns were a million times funnier when choreographed, and the pair won easily.

Check trick-training books and websites for ideas. If your dog shows a true aptitude and is the friendly, easygoing sort, you might find that joining a pet therapy group can be something you'll both enjoy, an activity that gives your dog a job while brightening the lives of other people. - by Dr. Marty Becker and Gina Spadafori