Shetland Sheepdog (Detailed Introduction)

For us, determining a person's age is generally easy just by looking at their appearance, but for dogs, this is truly a challenge because their appearance does not change much. So how to determine a dog's age has become a question. The method is to observe their teeth; a dog's teeth can well indicate its age, though this method only provides a rough estimate and cannot be very precise.

Newborn puppies have no teeth in their mouths. Usually, teeth begin to emerge at about 20 days old. By 4-6 weeks of age, the puppy's deciduous incisors will be fully grown. By 2 months old, all deciduous teeth will have fully grown and are white, fine, and sharp.

As the dog grows gradually, between 2-4 months old, they begin to replace their first deciduous incisors; at 5-6 months old, the second and third deciduous incisors and deciduous canines will be replaced. By about 8 months of age, all deciduous teeth in the pet dog's mouth will have been replaced by permanent teeth.

Generally, a 1-year-old dog's permanent teeth are fully grown, clean, and bright white, with pointed cusps on the incisors. At 1.5 years old, the first lower incisor’s large cusp wears down to be level with the small cusp, a phenomenon called cusp wear. At 2.5 years old, the second lower incisor’s cusp wears away. By 3.5 to 4.5 years old, the upper first and second incisor cusps wear away. At 6-7 years old, the third lower incisor cusp wears away, the canines become blunt and round, and the first lower incisor wears down to the root with an elongated elliptical wear surface; at 10 years old, the wear surfaces of the second lower and first upper incisors are elongated ellipses. By 16 years old, the dog's incisors fall out, and the canines are incomplete.

From this, it can be seen how to determine a dog's age—through their teeth, one can roughly estimate it. Of course, this method is not very accurate, but currently, there is no better way to determine a dog's age.