A popular misconseption is that dogs age 7 years for each calender year. In fact, canine aging is much morerapid during the first two years of the dog's life. After the first two years the ratio settles down to 5 to 1 for small and medium breeds. For large breeds the rate is 6 to 1, and for giant breeds the rate is 7 to 1. Thus at 10 years of age a Great Dane would be 80 years old, while a pug would only be 64.

Examining teeth is one of the best ways to determine the approximate age of a dog. Looking at the degree of wear is critical for adults. From a year-old canine to a graying, noble seventeen year old shepherd, how can you figure out the age of your dog who falls between these extremes? Start by looking at the teeth.

1. Look to the four front teeth of your dog, both in the upper and lower jaws, but particularly the teeth in the upper jaw. A dog has a very visible mark in his teeth which does not disappear completely until he is near six years old.

2. Observe the four front teeth in both jaws. Notice any jagged or uneven teeth, even in the form of a fleur de lis (but not quite as pointed as the jagged edge of a fleur de lis). The teeth will be white and clean. At 12 months old, a dog will be showing these characteristics. As her age advances, these marks will wear away and gradually grow smoother.

3. Examine all the front four teeth and look for half worn down marks. Not completely jagged, but not completely smooth either. Look also for increased tartar build-up around all teeth. At this stage in a dogs life, he will be three and four years old.

4. Look to the four front teeth of your dog, both in the upper and lower jaws. If you observe all teeth quite worn smooth and not at the least jagged, you may conclude the dog is nearly, if not six years old. When these marks are worn reasonably flat and even, as well as the teeth being quite level, your dog will be nearing ten years.

5. Observe for heavy tartar build-up and missing teeth. Your dog's age will be around ten to fifteen years.

• Teeth are only a rough indicator of a dogs age.
• Be aware that variations can throw off your estimate. For example, a dog that has received dental care will have better looking teeth than one which has not had such treatment. In some cases this will lead to an inaccurate and difficult determination.