One of the many things that make rats so unsettling is their large, yellow teeth. Yellow and orange teeth are a sign of poor oral hygiene in humans, but the opposite is true for rodents.
Rats have yellow teeth because their enamel contains iron, which is what makes their teeth yellow or orange. More importantly, iron makes the teeth stronger and more robust.
Rodent enamel differs from human enamel because they use their incisors for much more than just eating food, so they need extra protection from tough and abrasive materials.
Why Are Rats’ Teeth So Yellow?
As stated, rats have yellow teeth because they’re coated with iron-rich enamel. Enamel is a protective layer that coats the surface of a tooth.
It’s intended to defend against damage and infections by preventing bacteria from penetrating the rest of the tooth and weakening its structure.
Human enamel is composed of calcium phosphate, which is why our enamel is clear, making our teeth look off-white. Rats’ enamel is rich in iron, which gives the enamel its yellow-orange pigmentation.
The reason rats have so much iron in their enamel is because they need extra protection. Iron fortifies the enamel, making it thicker and harder than the enamel on our teeth.
We use our teeth to bite and chew our food, but rats use their incisors for much more. They gnaw on tough substances to create openings to crawl through, such as wood and synthetic materials.
Without the extra protection, they couldn’t navigate their way through rural and urban environments.
How Strong Are Rats’ Teeth?
Rats’ teeth are strong enough to chew through materials most houses are made of. It’s easy for them to get inside human living spaces by making holes through materials such as:
- Rusted metal
- Rusted Steel
- Cinder blocks
Rats’ teeth are so strong that few options are available if you want to stop them from making a path into your house.
You could build certain parts of your house from materials that are harder than rats’ teeth, but this method isn’t always viable.
Most materials that are tougher than rats’ teeth, such as quartz or high-speed steel, can’t be used in every part of the house, and they tend to be expensive.
Instead, it’s recommended that glass is used to cover paths made by rats. Although most glass has the same hardness rank on the Mohs scale, it irritates the inside of rats’ mouths.
Their teeth may be fortified with iron-rich enamel, but their gums and tongue aren’t.
Mohs Scale of Hardness
Mohs scale of hardness is an ordinal scale used to measure the hardness of certain materials. Rat teeth score 5.5 on the hardness scale, meaning that they are tougher than common:
Despite having teeth that are tougher than most metals, rats will rarely gnaw through them unless they are rusted. This is because it would take too much time to make a hole through metals unless they are weakened. So, rats will more often than not gnaw on wood, which scores 1 on the hardness scale.
How Many Teeth Do Rats Have?
Rats have 16 teeth: 4 incisors and 12 are molars. The incisors are the long front teeth at the top and bottom of the rat’s mouth.
They never stop growing, so rats need to gnaw on hard substances to shave them down. If they’re unable to shorten them, it becomes difficult for the rat to close its mouth and eat.
The molars are located in the back of the mouth. Due to their similarity to human molars, rats’ molars are often used in dental studies.
What Is the Structure of a Rat’s Teeth?
The structure of a rat’s teeth comprises three parts: pulp, dentin, and enamel.
The pulp is the center of the tooth, and it contains blood vessels and nerves. In other animals, the pulp is surrounded by the root of the tooth, which is hidden inside the gums.
However, common rats don’t have incisor roots. Their incisors grow continuously, so they can slowly regrow, even if a tooth breaks off entirely.
The incisors are the only teeth that rats can regrow. According to Laboratory Animals, rats have molar teeth similar to human teeth. Once an adult rat loses its molars, they’re gone forever.
The part that surrounds the pulp is the dentin, which is a living tissue containing small tubes. It’s very sensitive, so it needs to be protected by the enamel layer.
Can Rats Get Cavities?
Rats get cavities by consuming foods that eat away at their enamel and damage their dentin. Cavities aren’t a big issue for a rat’s incisors.
If a rat develops an incisor cavity, the tooth will eventually break off and regrow. Molars are different. Because rats can’t regrow their molars, they’ll permanently lose the tooth if they get a molar cavity.
Despite being capable of developing cavities, wild rats rarely get them. Their enamel is so strong that it can successfully keep out bacteria.
Facts About Rats’ Teeth
Here are some interesting facts about rat teeth:
- The top incisors tend to be a darker shade of yellow-orange than the bottom ones. That’s because rats primarily use their top incisors to gnaw on things, so they need extra enamel protection.
- Rats don’t have canines. Canines are primarily used by animals to rip and tear their food apart, so they use their incisors. If they need to grind the food, they use their molars.
- Rats’ incisors become visible 8-10 days after the rat is born. The first molars don’t appear from the gums until the rat is 19 days old. The last set of molars comes in when the rat is 35 days old.
- Rats’ enamel only coats the front of the teeth. The softer dental in the back is white and gets worn down faster than the front. This helps the incisors stay sharp.
What Does It Mean If a Rat’s Teeth Are White?
Rats have white teeth for the first few weeks of their life.
They have yet to develop their enamel properly, so their teeth aren’t coated with the iron-rich substance yet. It usually takes 21-25 days for a rat to fully develop its enamel.
If you see a small rat with white teeth in your home, a new litter has been born.
An adult rat with white teeth isn’t normal, signifying malnutrition. Adult rats are usually 16 inches in length, including their tail.