Unlike humans, most animals—especially  those living in the wild—don't eat cooked  

food. This provides their teeth  with protection from tooth decay  

because they aren't eating foods  that are heavy on refined sugar.

2.Microbacterial Flora

Animals' mouths, like humans', are  filled with both good and bad bacteria.

Streptococcus mutans, which thrive in high  sugar environment, is the primary cavity-causing  

bacterium in humans and animals. Animals  never ingest a lot of sticky carbohydrates,  

thus their mouths are never swamped with  this kind of bacterium. As a result,  

there are less tooth decay for non-human animals.

3. Life Span

Most of the animals that have teeth have far  shorter life spans than humans. So they simply  

just didn't get a chance to get tooth decay  before they die. And if you are wild animal,  

you probably will die very soon  after you get tooth decay since  

you won't be able to chew and  digest the nutrition you need.