What are the age groups of dogs? Let’s Explore

Thank you to Rachel Casey and Melissa Upjohn for their helpful comments on the early drafts of this manuscript.

13. Szabó D, Gee NR, Miklósi Á. Natural or pathologic? Discrepancies in the study of behavioral and cognitive signs in aging family dogs. J Vet Behav Clin Appl Res. (2016) 11:86–98. doi: 10.1016/j.jveb.2015.08.003

Seven years of age is commonly used as a threshold for the beginning of “old age” in dogs [e.g., (13, 40, 41)]. However, a number of more recent studies have used 8 years as a threshold for “senior” (e.g., 7, 8, 37)]. Although 8 years could be a good age to set this threshold, it is based upon classification of periods for one breed, the Border Collie, and the source material explaining the classification choice (42) is not in primary literature or accessible to this author. However, empirical support for setting 7 years as the beginning of old age comes from a recent study correlating age groups in dogs against signs of DNA aging (39), which led the authors to suggest that dogs between 2 and 6 years of age can be considered mature adults, and dogs aged 7+ years can be safely considered senior. The study did not account for extremely aged dogs by providing a geriatric group, however, and again, was based on just one breed.

15. Rollo CD. Growth negatively impacts the life span of mammals. Evol Dev. (2002) 4:55–61. doi: 10.1046/j.1525-142x.2002.01053.x

18. Kraus C, Pavard S, Promislow DEL. The size-life span trade-off decomposed: why large dogs die young. Am Nat. (2013) 181:492–505. doi: 10.1086/669665

It is commonly held that dogs age 7 years for every year that a human does. However, this serves as only a rough guide when converting and calculating your dog’s age. Dogs grow up very rapidly in their early years and then slow down.

Puppies and How to Take Care of Them

Life Stage No. 1: Puppy. Your dog is a puppy from the time its a newborn until its able to reproduce.

This happens at different ages, depending on the breed of your dog. Small breeds tend to reach sexual maturity earlier than larger breeds.

Weaning. Puppies slowly switch from their mothers milk to eating other foods when theyre 3 or 4 weeks old. They should be fully switched over from milk to food by the time theyre 7 or 8 weeks old.

Feeding. The number of feedings per day changes as your puppy gets older:

  • 2 to 3 months old: 4 times a day
  • 3 to 6 months old: 3 times a day
  • 6 months old to 1 year old (up to 24 months in larger breeds): 2 times a day
  • After age 1, feed your dog once or twice a day. Tiny dogs may need more frequent meals.

    Dental Care. Dogs may show signs of gum disease by age 4 — or even as early as age 1 in some small-breed dogs — if you dont take proper care of their teeth. So the right time to begin proper dental care is when your dog is still a puppy. To clean your puppys teeth, use a special toothbrush made for dogs or else use a clean piece of gauze wrapped around your finger. You can make your own toothpaste out of baking soda and water or buy one that is specially formulated for dogs. Never use toothpaste thats meant for people.

    House training. You can introduce the idea of house training as soon as your puppy is weaned. They are still developing, though, so dont expect them to learn quickly. By the time they are 4 to 6 months old, they can usually go without having accidents.

    Spaying and neutering. You may want to have your puppy spayed (removing females ovaries and uterus) or neutered (removing males testicles). These operations keep dogs from reproducing and having more puppies. They are usually done when your puppy is around 6 months old.

    Spaying and neutering while they are puppies rather than as adults can help prevent problems like breast cancer and testicular disease when they get older.

    Vaccines. Dogs need several rounds of vaccinations or shots during their first year. Talk to your veterinarian about which ones your dog needs and when to get them.

    In these three stages your dog is in the prime of their life. The ages for these stages may differ with each breed, but here are some guidelines:

    Life Stage No. 2: Junior. Now your dog is kind of like a teenager. Although they can reproduce, they are still growing, so are not quite an adult yet. Their age in this stage ranges from 6 to 12 months.

    Life Stage No. 3: Adult. Your dog is officially an “adult” once they have finished growing. They look and behave like a grown dog. Their age ranges from 1 to 7 years.

    Life Stage No. 4: Mature. Your dog has hit middle age! Their age is older than 7 years. Breeds that are smaller — as measured by weight, not height — tend to live longer than bigger dogs.

    While theyre usually easier to care for than puppies, grown dogs still need your help with a few things so they can live their best:

    Exercise. No matter their life stage, be sure your dog gets plenty of exercise. It will help keep them happy and at a healthy weight. Just don’t overdo it, especially in large and giant breeds, because their skeletons are not mature until about 2 years of age.

    Vaccines and visits to the vet. Take your dog to the vet every year for a checkup and vaccines to protect them against disease.

    Different Age Groups in Dogs