Teeth are tools that have evolved to specifically and effectively deal with an animal’s food. By examining the teeth of an animal, scientists can draw important conclusions about their lifestyle, diet and ecology. Typically, animals with broad, flat teeth are either predators that consume well-armored prey, or herbivores that need to digest tough plant material.
Caiman lizards (Dracaena guianensis) are aquatic creatures that have broad, flat, molar-like teeth. These 4-foot lizards live in the swamps, rivers and ponds of South America, where they hunt for their preferred food: apple snails (Ampullariidae). These heavily armored snails are immune to most predators, but the strong teeth and jaws of caiman lizards allow them to crush the mollusks and exploit them as a food source.
Adult Monitor Lizards
Some adult monitor lizards (Varanus sp.) predate on snails, clams and crustaceans. In order to crush their well-protected prey, some species develop broad, flat teeth. Nile monitors (Varanus niloticus) are one of the best-studied species that exhibit this tendency. Nile monitors also predate heavily on the eggs of Nile crocodiles (Crocodylus niloticus); the flat teeth may help them to grasp and crush these eggs as well.
Most grazing mammals have broad and flat molars in the back of their mouth. These molars help animals as diverse as deer, cows, giraffes and squirrels to cut, grind and digest plant material. Plant material is very difficult to digest, and some of these animals engage in rumination. In this process, the animal collects food with its mouth and chews it for a brief time. It then passes the food into a forestomach for partial digestion. Shortly later, the food is passed back up to the mouth for further chewing and is then finally swallowed. Many herbivores, including ungulates, lack top front teeth entirely; instead, they have a dental pad that helps to grip vegetation.
Omnivores consume plant and animal material. Often, omnivores have different groups of teeth for dealing with different food sources -- a condition known as heterodonty. Animals such as primates have canine and incisor teeth at the front of their mouth, which tear and cut animal-based foods, but they also have flat molars in the rear of their mouth for grinding plant-based food.
Stingrays and sharks share close branches of the evolutionary tree, but stingrays lack the sharp, curved teeth of their cousins. Rather than cutting and tearing, the stingrays’ teeth must be able to crush the tough shells of mollusks and crustaceans. During the breeding season, the males’ teeth grow long points so that they can effectively bite and grip the females during mating.
Alternatives to Broad, Flat Teeth
Birds lack teeth entirely, yet some eat vegetation. To help digest the tough plant material without teeth, some birds swallow small rocks. Once in a bird’s stomach, the rocks are termed gastric stones.The stones make the stomach function like a rock tumbler, breaking up the plant matter so that it is more easily digested.
- Animal Teeth: Kinds and Uses in Different Types of Foods
- Dr. Witson's Biology Lab Review: Animal Adaptation Review
- ThinkQuest: Teeth
- Nile Monitors: Everything About History, Care, Nutrition, Handling and Behavior; Robert J. Faust
- Journal of Herpetology: On the Jaw Mechanism of the Snail-Crushing Lizards, Dracaena Daudin 1802 (Reptilia, Lacertilia, Teiidae)
- Florida Museum of Natural History: Atlantic Stingray
- A-Z Animals: Giraffe
- Eastern Kentucky University: Bird Digestion
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