Pets age much faster than we do. The life span of a dog depends on its size or breed. In general, the larger the breed or size of the dog, the shorter the life span. For example, in a study of lifespans, only 13% of giant breed dogs lived to be over 10 years old. Conversely, 38% of small breed dogs live to be over 10 years of age.
Dogs are considered senior in the last 25% of their lives. Below is a list of the most common breeds with their life expectancies and age at which they are considered "senior".
When your dog is senior, make sure they have a senior check-up with your veterinarian.
| Breed | Lifespan | Senior Years |
| Affenpinscher | 12 - 15 years | 9 - 11 years |
| Afghan Hound | 10 - 12 years | 7.5 - 9 years |
| Airdale Terrier | 10 - 13 years | 7.5 - 10 years |
| Akita | 10 - 12 years | 7.5 - 9 years |
| Alaskan Malamute | 8 - 10 years | 6 - 7.5 years |
| American Eskimo | 13 years | 9.5 - 10 years |
| American Foxhound | 10 - 12 years | 7.5 - 9 years |
| American Staffordshire Terrier | 10 - 12 years | 7.5 - 9 years |
| American Water Spaniel | 12 - 15 years | 9 - 11 years |
| Anatolian Sheepdog | 12 - 13 years | 9 - 10 years |
| Australian Cattle Dog | 12 - 15 years | 9 - 11 years |
| Australian Shepherd | 12 - 13 years | 9 - 10 years |
| Australian Terrier | 15 years | 11 years |
| Basenji | 13 - 14 years | 9 - 10.5 years |
| Basset Hound | 10 - 12 years | 7.5 - 9 years |
| Beagle | 14 - 15 years | 10.5 - 11 years |
| Bearded Collie | 10 - 13 years | 7.5 - 10 years |
| Beauceron | 10 - 12 years | 7.5 - 9 years |
| Bedlington Terrier | 13 - 15 years | 9 - 11 years |
| Belgian Malinois | 12 - 14 years | 9 - 10.5 years |
| Belgian Sheepdog | 12 - 14 years | 9 - 10.5 years |
| Belgian Tervuren | 12 - 14 years | 9 - 10.5 years |
| Bernese Mountain Dog | 8 - 10 years | 6 - 7.5 years |
| Bichon Frise | 12 - 15 years | 9 - 11 years |
| Black and Tan Coonhound | 10 - 12 years | 7.5 - 9 years |
| Black Russian Terrier | 10 - 11 years | 7.5 - 8 years |
| Bloodhound | 9 - 11 years | 6.5 - 8 years |
| Border collie | 11 - 14 years | 8 - 10.5 years |
| Border Terrier | 13 - 15 years | 9 - 11 years |
| Borzoi | 10 - 12 years | 7.5 - 9 years |
| Boston Terrier | 14 - 16 years | 10.5 - 12 years |
| Bouvier Des Flandres | 8 - 10 years | 6.5 - 7.5 years |
| Boxer | 9 - 11 years | 6.5 - 8 years |
| Briard | 10 - 13 years | 7.5 - 10 years |
| Brittany | 12 - 14 years | 9 - 10.5 years |
| Brussels Griffon | 12 - 15 years | 9 - 11 years |
| Bull Dog | 8 - 10 years | 6 - 7.5 years |
| Bull Terrier | 14 - 15 years | 10.5 - 11 years |
| Bullmastiff | 8 - 10 years | 6 - 7.5 years |
| Cairn Terrier | 14 - 16 years | 10.5 - 12 years |
| Canaan Dog | 12 - 15 years | 9 - 11 years |
| Cardigan Welsh Corgi | 14 - 16 years | 10.5 - 12 years |
| Cavalier King Charles Spaniel | 12 years | 9 years |
| Chesapeake Bay Retriever | 12 - 13 years | 9 - 10 years |
| Chihuahua | 15 - 18 years | 11 - 13 years |
| Chinese Crested | 12 - 16 years | 9 - 12 years |
| Chinese Shar Pei | 10 - 12 years | 7.5 - 9 years |
| Chow Chow | 9 - 11 years | 6.5 - 8 years |
| Clumber Spaniel | 12 - 13 years | 9 - 10 years |
| Cocker Spaniel-American | 14 - 16 years | 10.5 - 12 years |
| Cocker Spaniel-English | 14 - 16 years | 10.5 - 12 years |
| Collie | 12 - 15 years | 9 - 11 years |
| Curly Coated Retriever | 8 - 12 years | 6 - 9 years |
