Assessing the Puppy’s Body and Behavior
To tell your puppy’s age, check to see if it’s starting to play and explore on its own, since that usually happens when puppies are 5-6 weeks old. Additionally, keep tabs on when it begins to eat solid food, which usually occurs at the 6 to 8 week mark. You can also look for signs that your puppy is becoming more active, chewing on things and playing more energetically, which typically takes place around 8 weeks. Watching your puppy’s growth can also give you clues about its age, since they grow the fastest between 8 and 16 weeks. For more information from our Veterinary co-author, including how to tell your puppy’s age by looking at its teeth, read on!
How to estimate a dog’s age
Birth to 2 weeks of age: Newborn puppies are born toothless and with their eyes closed. These features can be used to identify puppies that are less than two weeks of age. Puppies this age spend most of their time rooting, suckling, and sleeping.
2 to 5 weeks old: The eyes open at two to three weeks of age although vision is poor. There will still be no teeth present. Puppies this age become more engaged with their environment and begin to explore their surroundings.
5 to 8 weeks old: This period is marked by the eruption of deciduous (baby) teeth. Yes, that’s right: Dogs, like humans, have two sets of teeth. The first set begins to erupt at five to six weeks of age, and the full set is generally in place by eight weeks. These teeth are very sharp, and people with puppies in this age group will be painfully familiar with them. By the time a puppy is eight weeks old he or she will be in full-on puppy mode with periods of active playing, exploring, chewing mixed with periods of passed-out sleep.
8 to 16 weeks old: The deciduous teeth are in place, but the space between them will increase as the jaw and face grow. They will also begin to appear disproportionately small since they stay the same size while the puppy grows around them. This is a period of intense activity, growth, exploration, and learning for the puppy.
16 weeks to 8 months old: At around 16 weeks the baby teeth begin to fall out and be replaced by permanent teeth. This process starts at the front of the mouth with the small teeth called incisors, and then works its way back, generally in a symmetrical fashion. The puppy’s mouth may bleed slightly (or his or her breath may sometimes smell like blood) as the baby teeth fall out. The deciduous teeth are generally gone by five months, and the permanent teeth generally are fully erupted by eight to 12 months of age.
8 months to 24 months old: Most dogs have reached their full height by eight to 12 months of age (although some giant breeds continue to grow for up to two years). They are adolescents — not quite puppies, but not quite mature dogs. Like adolescents, dogs in this age group go through puberty (if they aren’t neutered or spayed). And like adolescents, they are generally clumsy and awkward and they may have skin problems (puppy mange often strikes around this time, or sometimes a bit earlier).
2 to 3 years old: Most dogs’ physical development is complete by two years of age. Alas, it often is not long after this that time to begin to take its toll. The first sign of aging usually is visible in the mouth: dental calculus and even gingivitis will be present in the majority of dogs by three years of age if their teeth aren’t brushed.
3 to 7 years old: Humans this age would be considered in the prime of their lives. However, some signs of aging will occur during this time. Dogs whose teeth do not receive attention (either through brushing or professional dental work) will generally experience progressive dental disease. Gray hairs may develop on the muzzle. Activity levels will slow.
7 years and beyond: As I mentioned above, different sizes of dogs age at different rates. Seven years is generally the time at which these differences become pronounced. Many larger breeds of dogs will show significant signs of arthritis (manifested by mobility problems), while smaller dogs may not exhibit these issues for another three to five years. At seven years of age most dogs’ eyes will become slightly cloudy. This natural aging phenomenon is a type of cataract, but it does not significantly compromise vision or quality of life. They may develop wart-like growths on their skin (similar to moles in people), or soft growths called lipomas underneath the skin. Their voices may change to a raspier tone. Smaller dogs may begin to show symptoms of collapsing trachea (manifested most frequently by coughing when active). Hearing and vision may fail (although the vision loss is not usually linked to the cloudiness in the eyes). Mobility may progressively deteriorate. Dental disease may become profound and if the mouth is not cared for teeth may fall out.
By the age of 12 weeks, your puppy’s baby teeth will start to come out gradually in a symmetrical fashion. After that, permanent teeth make their way out and begin to erupt.