Seniors and Geriatrics
Veterinarians label aging canines as either “senior” or “geriatric.” A dog is considered to be a senior when she has lived two-thirds the average lifespan for her breed. The expected lifespan of a healthy Chihuahua is roughly fourteen to sixteen, so a Chi would become a senior at the age of ten.
The point at which a Chihuahua is old enough to be labeled a geriatric is when she is halfway through the final third of her expected lifespan. In other words, a Chi would be considered a geriatric when she's thirteen years old.
As your Chihuahua ages, she will undergo changes. These changes are generally subtle and often occur over a long period of time; however, they will affect your Chihuahua both physically as well as mentally. Anticipating these changes and knowing how to best address them will go far to extend the quality of your Chihuahua's final years with you.
The average life expectancy of a purebred dog decreases as the height and weight increases. It should be no surprise then that toys have a lifespan that is nearly twice that of many large-and giant-breed dogs.