From the tiny teeth found in a snail’s mouth to the long tusked teeth that grow from an elephant’s mouth, teeth in the animal kingdom come in all shapes and sizes. But did you know that, unlike humans, some animals have more than two sets of teeth?
Often, as their teeth become damaged or weaker with use, new teeth grow in their place. Essentially, out with the old, in with the new.
So, what are some animals with multiple sets of teeth?
Animals with multiple sets of teeth are called polyphyodonts. Mammals with multiple sets of teeth include kangaroos, manatees, and elephants. Bearded dragons, geckos, snakes, alligators, crocodiles, monitors, iguanas, and other toothed reptiles may also be polyphyodonts. Finally, sharks and other toothed fishes have multiple sets of teeth.
Below, we’ll take a closer look at these animals capable of tooth regeneration with their multiple sets of teeth. I’ll also talk about how often these teeth erupt and contributing factors to why animals need to be able to replace their teeth.
Manatees are another mammal that is constantly replacing its teeth. They spend the majority of their time in the water grazing and are hungry animals, eating around 4-9% of their body weight every day. That’s a lot considering the manatee weighs between 800 and 1000 pounds!
Manatees don’t have biting teeth because they don’t really need them to eat aquatic plants. Instead, they have grinding teeth that help with the foods they break down.
These grinding molars are constantly being replaced throughout the manatee’s lifetime, likely because of all the sand that is in the plants they eat wearing them down. As teeth get weaker, they move forward at a rate of about .4 inches per month and new teeth erupt in the back of the mouth.
Kangaroos are one of three known mammals with multiple sets of teeth. They are known grazers and like to spend the dusk and dawn hours grazing on grass, leaves, flowers, and other plant matter.
Since kangaroos do not have the stomach of cattle for grazing, they aren’t able to break down food as well. This means to get proper nutrition, they have to chew food really well before swallowing. In fact, kangaroos often regurgitate food and chew it twice before allowing it to digest.
All this chewing can break down teeth, so it’s good for the kangaroo that its teeth are constantly being replaced. New teeth grow in the back of the mouth and older teeth migrate forward until they are eventually pushed out of the mouth.
In addition to their massive tusks that never stop growing, elephants have massive molars used for grinding the plant material that makes up an elephant’s diet. As the molars are worn down from use, they start to migrate forward and are eventually pushed out of the elephant’s mouth.
New teeth are formed in the back of the jaw to replace those that fall out. Elephants have six sets of four teeth, so a total of 24 extra teeth. It’s believed the last set emerges around age 30 and elephants begin to lose their final set of molars around age 65.
Additionally, each set of molars that emerges is a little bit bigger than the last. Scientists can even determine the age of elephants in the wild by measuring their molars.
Even though elephants have a lot of replacement teeth, they do eventually run out. Tooth loss is the leading cause of death for healthy elephants in the wild because as elephants lose the ability to chew food, they no longer get the nutrition they need.
Bearded dragons are unique because they are one of the few vertebrates known to have both polyphyodont and monophyodont teeth. Though bearded dragon teeth are especially small and hard to see at birth, they need them to chew through vegetation and insects.
According to researchers, bearded dragons regrow their teeth using stem cells produced in other areas of their bodies. The teeth in the back of their mouth are pleurodont and capable of regrowing, which makes sense because this is where most of the chewing takes place.
Geckos are another popular reptilian pet, but did you know they are constantly losing and replacing their teeth? They have around 100 teeth in their mouth and replace these teeth every 3-4 months.
Like bearded dragons, the leopard gecko has been observed using epithelial stem cells to help with tooth regeneration. There isn’t a known timeline for this, but scientists have observed that once a tooth is lost, the gecko won’t lose adjacent teeth until it starts to grow back.
Generally, it takes a geck about 2-3 months to fully regrow a tooth. Likely, losing them in this pattern prevents there from ever being a time when the gecko can’t eat.
Most people are aware that some snake species have fangs that protrude from their mouths, but fewer people are aware they also have teeth. Certain snakes have thin, sharp teeth that actually aren’t very strong. In fact, it’s pretty common for snake teeth to break.
Instead of using their teeth for chewing, many species have rear-curved fangs that point slightly toward the back of the snake’s mouth. Some snake species have teeth back here that inject venom, too, but those that don’t just use their teeth to help pull prey toward their throat because they swallow it whole.
Of course, with their teeth being so thin, struggling prey often breaks snake teeth. Snakes are fortunate because, like many other reptiles, those that do have teeth like these are able to regenerate them.
Alligators and Crocodiles
While alligators and crocodiles are two completely different animals, they do have about 93% genetic similarity. With that in mind, humans share 93% genetic similarity with macaques, too.
One of the features they do share, however, is their many teeth that are constantly being replaced. Alligators and crocodiles regrow their teeth in sets. There is constantly a new tooth growth under the old, aging tooth so that it’s ready whenever the old tooth does fall out.
In the case of crocodiles, one theory is that these replacement teeth are necessary because of how thin a crocodile’s tooth enamel is. Crocodiles have really powerful jaws that put a lot of pressure on their teeth. What they don’t have, however, is strong enamel.
This is why their teeth break down over time. It also explains why they’d need to have the ability to replace these teeth- as carnivores, crocodiles and alligators rely on their teeth to kill and eat prey.
Iguanas, Monitors, and Other Reptiles
There are always new surprises in the animal kingdom, so it’s hard to say that something applies to an entire species. That being said, many toothed reptiles are polyphyodonts with multiple teeth sets. It would take too long to list every species, but iguanas and monitors are on the list.
Reptiles replace their teeth using iguanid or varanid regeneration. Iguanid regeneration essentially means the teeth grow in the same place as the original tooth, whereas varanid regeneration refers to the new tooth growing behind the original tooth.
Sharks and Megalodons
Like the reptiles mentioned so far, sharks never run out of replacement teeth. These teeth aren’t stored in their massive jaws. Instead, they use stem cells to trigger the regrowth of teeth once they are lost.
Not only do sharks regrow teeth, but they regrow a lot of them. The average shark has anywhere from 50-300 teeth and some species like the frilled shark are on the high end of that range. The number and type of teeth vary depending on the species.
The many types of shark teeth include dense, flat teeth that are used for grinding crustaceans and mollusks, needle-like teeth for gripping slippery fish, and pointed lower and upper teeth that resemble triangles, used for tearing prey into bite-sized chunks.
While megalodons are an extinct species of sharks, they’re still worth mentioning as an animal with teeth that are constantly being replaced.
Actually, most of what researchers know about megalodons came from studying their teeth. Scientists believe they’ve been extinct for millions of years and because sharks do not have bones, there were no skeletons of this massive creature.
What they did leave behind were massive teeth. Scientists have also found skeletons of whales with markings from a megalodon’s serrated teeth (and even the tips of the teeth in some cases), which suggests these massive creatures could open their jaws wide enough to swallow a whale.
Plus, in addition to having one of the biggest sets of teeth in the animal kingdom, it’s likely that just like sharks, megalodons would lose their teeth as they were damaged or became weaker with use.
Megalodon teeth have been found off the coast of every continent except Antarctica and there have even been breeding grounds (like this one in Panama) uncovered.
Like sharks, other species of toothed fish are known for losing and regrowing their teeth.
That being said, there are more than 20,000 estimated fish species in the world and probably just as many undiscovered, so it’d probably be pretty hard to list them all. Plus, while all these species have been discovered, they haven’t necessarily been studied in depth.
It’s generally believed that many toothed fishes regrow their teeth as they lose them over time. The frequency with which this happens varies. For example, the Pacific lingcod loses and regrows 20 teeth every day, while the alligator gar loses between 2,000-3,000 teeth in its lifetime.
Plus, not all toothed fish lose and regrow their teeth. Triggerfish, for example, have long teeth that never stop growing- so they don’t actually have multiple sets. Some toothed fish that are polyphyodonts include the goliath tigerfish, payara fish, piranhas, and the Northern pike.
Why Do Animals With Multiple Sets of Teeth Need Multiple Teeth?
When it comes to the animal kingdom, it does little good to ask why because the truth is, we rarely can give a definitive answer. All we can do is infer or hypothesize about these things.
That being said, many animals with multiple sets of teeth seem to be influenced by their diet. In the case of elephants, for example, their teeth are worn down by the rough fibers of the foods that they eat. Having replacement teeth ensures that even as teeth are worn down, the elephant can continue eating and essentially survive.
What Animal Has the Most Sets of Teeth?
It’s hard to say which animal has the most sets of teeth. That being said, the animals like toothed fishes, sharks, and reptiles rely on stem cells to regrow teeth, so they don’t really ever run out. It’s basically a never-ending supply of teeth.
This means that they never have to worry about running out of teeth, so I guess it’s up to how many are lost in their lifetime. Any of them could be contenders.
What Is a Polyphyodont?
When you start talking about animal teeth, animals are classified as polyphyodont, diphyodont, or monophyodont.
Polyphyodonts are animals that have multiple sets of teeth. They are constantly shedding teeth, sometimes losing them one at a time and other times losing them in sets. It varies based on the animal.
Diphyodont basically describes animals that have two sets of teeth. Humans are diphyodonts because we have children’s teeth that are replaced by permanent adult teeth, and then we never get more.
Animals that only have one set of teeth throughout their lives are monophyodonts, and there are fewer animals in this category. That being said, there are also some animals that have no teeth at all!
What Mammals Are Polyphyodonts?
Scientists have discovered around 54,000 different mammal species living on the earth. Of all these animal species, only three are known to be polyphyodonts, including manatees, elephants, and kangaroos.
Understanding how animals with multiple sets of teeth regrow theirs is fascinating in the world of dentistry. Who knows? Maybe one day people will be able to regrow their teeth instead of needing to get dentures in old age.
While there are only three known mammals that are polyphyodonts, or animals that regrow their teeth, there are many reptiles and toothed fishes that have this ability. This is pretty important when you’re an animal. After all, they can’t go to the dentist!