Knowing your chihuahua's age can help you make important decisions on its care, such as when to start feeding adult or senior dog food, when to provide more time to rest and when to increase vet checkup frequency. It is also comforting to have an idea of how much longer your dog might live since these little canines are like part of the family. All chihuahuas are different, so the age you determine won't be 100 percent accurate, but you can make an educated estimate based on physical characteristics and growth measurements.
Ask your veterinarian, dog groomer or a local dog enthusiast. These professionals handle chihuahuas of different ages and can provide insight on your dog's age based on its appearance and energy level.2
Examine the color and shape of your chihuahua's teeth and compare them to the age estimate chart in the Resources section. Age can be estimated based on how yellow or worn down the front and back teeth are.3
Weigh your dog and measure its height and then repeat 2 weeks later. The average chihuahua is full grown by 8 months, so if your dog's measurements are still increasing, it is likely under that age.4
Have the vet check your dog for cataracts, which is cloudiness in the pupil commonly found after the age of 7 years old in chihuahuas. If your dog has cataracts, it is probably at least 7 or older.5
Examine the color of the hair around your chihuahua's eyes and mouth. This hair begins to turn gray or white around 10-11 years old.