The bull shark has more teeth than any other vertebrate. It not only has about 350 teeth at any one time but replaces its teeth constantly throughout life and may go through as many as 35,000 teeth. The toothiest mammal is the long-snouted spinner dolphin with up to 252 teeth.
While some invertebrates like snails have structures referred to as teeth, true teeth are found only in vertebrates and consist of multiple layers and roots that are covered by gums. Living animals use teeth to help break down food and as weapons against predators or prey. Teeth are the hardest parts of the body and may be fossilized even when bones are not, giving archaeologists and palaeontologists valuable clues about an animal's diet and habitat.