The type of teeth an animal has depends on its normal diet. For example, a herbivore animal will require a different type of tooth to eat grass than the type of tooth a carnivore animal will need to eat meat. The domestic animals have a baby or deciduous set of teeth which fall out and make way for the permanent set of teeth to replace, like humans do. Dogs have twenty eight baby teeth and forty two permanent teeth. The baby teeth emerge between three to five weeks old. The permanent teeth begin to erupt at four to five months old. All of the permanent teeth have emerged by seven months of age.
It is possible to determine age relatively accurately by examining the teeth. In a young dog, the age is based on the time of tooth eruption. In older dogs, a veterinarian can estimate the age by examining the wear patterns on the permanent teeth. However, this is more difficult in miniature, toy and small dogs.