Sharks are the subject of multiple horror movies based on the idea that they’re violent, man-eating creatures. But is this an accurate depiction?
Sharks are in fact apex predators, and one reason they’re so well-made for predation is their never-ending supply of teeth.
Shark teeth do grow back, even if they don’t fall out due to accidents or injuries. Sharks’ teeth are continuously growing and replacing themselves. This ensures sharks always able to dominate their environments as predators. A shark can regrow their teeth thousands of times throughout their lifetimes.
Teeth Are An Important Part Of Shark Anatomy
We associate true teeth with being a part of a mouth, but a shark’s whole body utilizes teeth-like structures. A shark’s skin has scales known as “dermal denticles.” The literal translation of this phrase is “tiny skin teeth.”
These scales are thin but durable plates that look similar to teeth. They layer on a shark’s skin to offer chainmail-like protection and drag reduction.
However, it is a shark’s true teeth that put them at the top of their food chain. Sharks have few natural predators and are an important part of the ecosystem. They keep other oceanic populations in check.
The teeth on the lower jaw hold their prey in place while the upper teeth slice them open.
Shark Teeth Always Grow Back
A shark’s true teeth are in almost constant use, and sometimes they can become damaged or lost, exactly like our own.
If they could not replace these teeth, sharks would not be able to attack their prey or defend themselves. So, their bodies are always growing new teeth.
Sharks have multiple rows of teeth on their upper and lower jaws at all times. When the first row of teeth become damaged or lost, there’s a new tooth already growing behind it.
Their teeth aren’t always lost from outside events, either. All sharks are born with teeth already grown. They will replace these teeth at regular intervals throughout their lives. A shark may lose a tooth every week in some cases.
One shark could go through thousands of teeth in its lifetime. Some sharks may develop a new set of teeth as often as every two weeks.
How Sharks Lose Teeth
Since shark teeth are in constant use, nature has given sharks a way to replenish them with conveyor-belt-like construction. New teeth grow in rows and then rotate forward until they replace old or missing teeth.
A tooth doesn’t even have to become damaged or lost to need a replacement. Shark teeth automatically swap out throughout their life.
Shark teeth are more likely to fall out than human teeth because of the anatomy of their jaws. Their teeth do not root straight into their jaw or even the gum tissue.
Sharks have a membrane called the tooth bed, instead. Not only does this tooth bed contribute to the conveyor-belt movement of the teeth, but it also makes the teeth easier to dislodge.
Without the sturdy rooting into the jaw or gums, the teeth are more likely to fall out after attacking another animal.
Do Other Animals Have Many Sets Of Teeth?
Humans only have two sets of teeth throughout their entire life, through a process called “diphyodonty.” We’re unable to produce more once those are gone, but this is not uncommon for mammals.
Elephants, kangaroos, and manatees are some of the only mammals who have more than two sets of teeth throughout their life. However, even these animals have a set number of teeth. It’s only reptiles and fish (like sharks) that can continuously grow new teeth.
Not all fish and reptiles can grow teeth multiple times, but over 50,000 species can. For instance, geckos replace all of their teeth every few months. They’ll grow between 1,00 and 4,000 new teeth in their lifetime.
Then you have rodents who only have one set of teeth their entire life, but that set grows non-stop. This is why rodents exhibit gnawing behavior. It keeps the teeth trimmed and sharp, so they don’t cause themselves injury.
Sharks use their teeth as their main form of attack. Without them, they would not be the apex predators they are. Therefore, it’s important that they keep their teeth throughout their lives, and that they keep them sharp.
To do so, sharks can regrow their teeth over and over again throughout their whole lives. Even if the teeth don’t suffer damage, old teeth will be replaced to ensure a shark’s teeth are always in peak condition.