Some of the most interesting animals have teeth outside their mouths. We usually think of these "teeth" first when we hear their names: elephant, narwhal, walrus, warthog, etc. What do they use them for? Are they necessary for them to survive?
We will explore these questions by discussing some animals with external teeth that may surprise you!
Yes, an elephant's tusks are teeth! They are long incisors, front teeth that grow forward beyond the mouth of this mammal. The tusks have a smooth surface and a gently curved shape, and they continually grow throughout an elephant's life.
You may have heard that elephant tusks are made of ivory, so how can they also be teeth? The answer is simple - ivory is made of dentine (a hard, dense, bony tissue) wrapped in a thin layer of enamel (the hardest tissue in an animal’s body). The tusk also has a pulp cavity (that holds nerves and blood vessels) - but this is only in the part of the tusk inside the head. Do you remember what teeth are made of? A layer of pulp surrounded by dentin (dentine if you use British English), covered by enamel. So, they have the same main components. However, ivory is unique when viewed in cross-sections - it is made of criss-cross lines that form a series of diamond shapes.
Elephants use their tusks as tools to adapt their environments to their benefit and to show dominance over other male elephants. Tusks have nothing to do with biting or chewing but help defend them against attackers. They also use their tusks to dig and create holes. Tusks are unnecessary for the elephant to survive, but they certainly make it easier!
Interestingly, female Asian elephants do not have tusks at all, but female African elephants do. African male elephants usually have longer tusks than females and have a pair of tusks growing on either side of the mouth. The longest and heaviest African elephant tusk ever recorded is 236 pounds and 11.5 feet long!
Let's get to one of the smallest animals with teeth outside their mouths! The Naked Mole Rat, a native of East Africa, has large protruding teeth outside its upper and lower lips. They use these teeth to dig through the dirt and mine for food and shelter. With their teeth outside, they can keep the dirt from getting in their mouths.
Naked Mole Rats are hairless, can live for up to 31 years, and have never had a single instance of cancer ever known or recorded!
The narwhal also has a tusk, which is a tooth outside its mouth - although some people call it a horn since it looks like illustrations of a unicorn horn. The males have a long, straight tooth protruding from the left upper jaw that grows in a counterclockwise spiral. It can get as long as two to three meters and is very flexible, bending a foot in any direction. Female narwhals usually don’t have tusks. Narwhals don’t have teeth in their mouths and swallow their prey (fish) whole!
While we don’t know everything about the purpose of a narwhal’s tusk, we do know that they don’t use their tusk for fighting. Strangely, they are known to rub them together with another narwhal's tusk to clean them. The tusk senses the environment around it, such as if prey is nearby, and certain types of changes, like differences in water temperatures and salt levels.
Much like the narwhal, walruses live in the Arctic and sub-Arctic areas. Walrus males and females have tusks, but male tusks grow much longer and wider than females. Walruses use their tusks to aid in climbing onto ice in the water and dig up clams to eat. They do use them to defend themselves, and the males may use them during the breeding season to fight.
Walrus tusks are canines that can grow as long as 40 inches and weigh as much as 12 pounds! These walrus teeth are ivory (like the elephant’s tusks!), but their protective enamel coating wears away during their youth, making them susceptible to wear and bacterial infections.
The Warthog is a native of the African Savannah. They tend to take over the burrows of other animals for shelter and to raise their young in the grasslands and woodlands.
Warthogs run as fast as 30 miles an hour when trying to flee from predators! They will ward off the attack if cornered using their lower tusks, which can be anywhere from 6 to 24 inches long! While warthogs are peaceful animals and do not fight unless provoked, males may fight and use their tusks to show dominance over other Warthogs during mating season.
You will find babirusas in Indonesian rainforests. The babirusas are otherwise known as deer-pigs. Both male and female babirusas have a pair of lower tusks growing upward. Males also have upper canines that emerge from each side of the upper jaw and curve up and over the face towards the forehead. If the male does not grind off the upper tusks regularly, they can grow long enough to penetrate the skull and even kill the animal!
The babirusas do use their tusks to fight among themselves. The upper tusks are used for defensive maneuvers, and the lower tusks are offensive weapons.
The tufted deer is another interesting animal with teeth outside its mouth. Although its body is small, it has two protruding fangs at each side of its mouth that can be as long as one inch. The males use their tusks to defend against predators trying to enter their territory or fight with other males over mates.
The tufted deer lives in southern China, in the eastern Tibetan mountains and the lower coastal mountains. They prefer being active only at dawn and dusk and like the forest and shrubby habitats.
Most animals with external teeth are not native to North America, so we must visit our zoos here in the United States to see them. One animal we see at the zoo that we may think has an external tooth is the rhinoceros. Fun fact - their horn is not a tooth. It is made of keratin, the same material that our fingernails are made of!
Why don’t humans have teeth outside their mouths? When you look back on why these animals have external teeth, you see that humans don’t need them. The main reasons that the animals have teeth outside their mouths are:
Just as humans need healthy teeth, so do animals. Painful, cracked, or broken tusks or fangs can leave an animal defenseless or unable to provide food for themselves. In the wild, this can be a detriment to an animal's health and well-being, just as it can for humans.
Please don’t forget to make an appointment with us to keep your teeth as healthy as possible. We look forward to seeing you!
