When you think of carnivorous animals, the image that probably comes to mind is one of a stealthy hunter with razor-sharp teeth, ready to pounce on unsuspecting prey. And although many carnivorous animals indeed have very sharp teeth—such as the tiger, whose canines are perfectly designed for tearing flesh from its prey—this isn’t the whole story. Almost all animals that have been given the “carnivore” label have sharp teeth for a very good reason. Carnivores eat meat. And while the meat is an excellent source of protein, vitamins, and minerals; it also requires a lot of work to digest. That’s because most meat consists of tough protein fibers and bones made out of calcium phosphate crystals—a substance known as hydroxyapatite.
Why Are My Teeth Sharp?
Teeth are designed to puncture and tear, not crush and grind. Since mammals have two sets of teeth (‘baby teeth, also called deciduous teeth, followed by permanent teeth), they need a way to transition between the two. This is where sharp teeth come in handy. The sharp edges of teeth are useful for more than just biting. They aid in digestion, grooming, and even skin healing. A mammal’s mouth has many uses and sharp teeth help it complete these tasks efficiently.
What Is Hydroxyapatite?
- Hydroxyapatite crystals form the hard structure of bones and teeth.
- In vertebrates (animals with backbones), the hydroxyapatite crystals are part of the tooth enamel, which is a mineralized layer on the tooth surface. This is especially true for carnivores that eat tough prey.
- Carnivores with smaller teeth have to work harder to chew up their food. Over time, they have evolved with extremely sharp teeth capable of shredding away bone and protein fibers to get at their food’s most nutritious parts—and their ability to chew has been optimized over millions of years for this purpose, due to natural selection for eating well!
- In some animals with small teeth, the rear part of their skull has evolved to fit into their mouth, and so those animals have encased their brain in a little bone dome for eating.
- Some fish may have extremely sharp teeth for this reason—to avoid having to eat hard-shelled prey as opposed to soft-shelled prey.
- Some sharks crush their prey in their mouths before swallowing it whole, which is energetically costly but prevents the meat from being digested in the intestines, where it would be quickly picked apart by bacteria and putrefied.
- Chitin, an organic compound that forms part of the exoskeleton (hard outer layer) of insects or crustaceans (the tough body parts that certain animals such as lobsters or crabs have), has been shown to occur naturally in bone tissue of carnivorous insects such as roaches, termites, and ants—and they use this chitin as a defense against attacks by other insects or predators by grinding it up within the bite wounds made on these predators.
Why Are Teeth So Important?
- Teeth are a primary mode of defense against predators. They help the animal to kill and eat prey, and keep their mouth free of regurgitated food.
- Unlike most other animals, carnivores have teeth because they have evolved to be meat-eaters during evolution. They use their teeth as tools for killing and eating prey, whereas herbivores use their teeth for breaking down and extracting food from plants; some omnivores (animals that eat both flesh and plants) use their teeth for both purposes.
- Teeth help carnivores to break apart fleshy prey and deposit it into the stomach so that it can be digested within hours or days, rather than weeks or months. This requires amazingly sharp precision—and thus is why some carnivorous mammals like dogs, cats, bears, foxes, hyenas, and indeed lions as well as wolf-dogs like dingoes all have extraordinarily sharp canines. If a predator missed its mark with its bite but got lucky by accident when attacking its prey’s soft body parts like skin or lungs instead of bones (which are harder to break with the same level of force), it could die from infection due to bits of its prey sinking into open wounds in its mouth from an infected bite wound—a very painful way to go!
- Although it may seem obvious to us, teeth are not just for killing prey and keeping our mouths free of food. Teeth do very important tasks in the digestive process as well. Something like a crocodile’s tooth, for example, plays a critical role in breaking down plants into digestible material (like tannin used by other mammals to extract tanning agents from their prey’s hides). Animals with excellent teeth compensate for the lack of an intestinal tract by having more sophisticated digestive systems that use enzymes and acids unlocked in the stomach walls. These systems require an active bacterial population in the mouth: scientists have shown that bacteria living in the mouth of carnivorous animals is higher than those present in herbivores’ guts.
- The sharpness of carnivorous teeth comes from complex processes inside each tooth called dentin—the hardest substance between enamel (the outer layer) and bone or nerves (harder still). During a baby shark’s early developmental process when its jaw grows into shape and hardens, it secretes a mixture of proteins called dentinogen from numerous cells all over its jaw around each tooth, but this doesn’t make for very good dentin yet—since there are no lines present to form a long-lasting structure that can maintain its shape as it grows out into adulthood! Instead, one type of protein called amelogenin forms long strands around these teeth while another protein called collagen is only loosely bound to the rest of the dentin. The amelogenin acts like glue to hold everything together and from there, the collagen starts to get woven into the tooth over time. Already at this early stage of development in sharks, dentin can be found in the cuticle around each tooth, which allows it to be hardened by forming a sort of sandwich between two thin layers of dentin (the inside and outside) in which calcium phosphate crystals serve as an additional layer. The calcium phosphate acts as a form of hardening agent while simultaneously holding everything together so that dentin is strengthened instead of simply being ridges that may not last long enough to use for chewing!
- In humans, because teeth are no longer needed for eating meat, they have all been replaced with implants that look like implant teeth on the outside! Instead of using teeth for chewing food, we live with implants that do all the work for us instead (which are sometimes called “false teeth”). These replace lost teeth or other parts such as wisdom teeth. An implant-supported natural replacement has shown to be nearly identical functionally and histologically (when examined under a microscope) to permanent bridges or other types of dental prosthetics from a dentist’s perspective—which would make this one major success story for what first appears to be an unlikely outcome!
Adaptations For Eating Meat
- Sharks come in all shapes and sizes, but the biggest sharks are often the ones that get eaten by larger predators. These large sharks have evolved traits to make themselves look dangerous and as a result, have characteristic sculls that are closer to a cephalopod with an extension on its back. This was so it could extend its body out of the water and signal danger to other predators (including humans) (p. 23)! In fact, “The Great White Shark Carcharodon carcharias is well known for its long and massive tail, which some researchers show to be used in hunting by propelling the shark forward like an oar” (p. 23)!
- Sharks began their life in water where they were born with gills behind each eye, but they move onto land where they develop lungs because this will help them hunt better! Scientists speculate these adaptations may help these sharks find prey more easily on land; because although the line between land and water is quite thin in certain environments such as the oceanic waters around Japan, the line is exceedingly sharp when it comes to deserts or tundra!
- The metabolism of fish differs from that of mammals—they have very high oxygen needs compared to our needs compared to ours; therefore shark species can keep swimming around for longer periods than we can due to their smaller bodies. Some sharks can even go for several months without eating at all! On average there are about 41 species of shark and these sharks have dominated the oceans until recently when our industrial fisheries killed them off. Sharks make up about 16% of marine species (p. 25)!
- Sharks have a variety of different teeth that they use for different tasks. Some sharks’ teeth are sharp and serrated while others are flat and smooth unlike most mammals with their tusks! The majority of sharks can only eat very small prey such as squid or fish, but some of them can be huge! Whales—which fit in between sharks and the largest land animals—can weigh up to 100 tons so find out how much bigger large whales are!
Conclusion
Sharp teeth may be more convenient for eating meat, but they also come with a higher risk of tooth decay and other dental issues. And while it’s true that carnivores have evolved to have sharp teeth, that doesn’t mean that humans should follow suit. Humans eat a far more varied diet than carnivores do, so our teeth don’t need to be as sharp. While many of us will experience tooth decay if we don’t take care of our teeth properly, that doesn’t mean we have to have sharp teeth—or even cavities. If you want to keep your teeth healthy, you should make sure to brush your teeth regularly and see your dentist at least once a year.
