Question

why animals teeth are white? even they dont brush like us daily

Answer 1

Sharks


Teeth appear to have first evolved in their ancestors. Since they use their teeth for everything from defense to attack, from chewing mollusks to fish, replacing their teeth helps them more than taking care of them. They get a new set of teeth every two weeks. Some sharks (ground sharks) shed approximately 35,000 teeth in their lifetime.


Elephants


They have two special incisors (tusks) that they take care of by brushing them while chiseling the bark off trees and digging holes. These incisors keep growing. Moreover they prefer and mostly use one tusk more than the other so that when one wears down, they still have another one left. The molars of the elephant keep getting replaced till 40 years of age. The last set can last for 20 years.



Canines.


This includes dogs, wolves, and members of the feline family. The saliva of canines has a very high pH. This prevents the enamel from demineralizing and they are less likely to get cavities. Along with that they have the "bone" tooth brushes as Will Falconer puts it. 


Rodents


If you had hamsters as pets, you'd see that the thing they like to do most is chewing. And not just chewing, they chew really fast. That's their way of taking care of their incisors that grow continuously (the process is called aradicular). This sharpens their teeth too. In some rodents like guinea pigs, the molars keep on growing too.


Crocodiles


Crocodiles and other reptiles replace their teeth too. A juvenile crocodile replaces around 1tooth/socket every week. As they grow old the rate slows down



Herbivores


In herbivores like horses, once they get their permanent set of teeth, they grow at around 1/8 inches every year and as the horse ages, the upper grinding surface keeps on wearing down. When old, the horses may almost be toothless because of the wear.