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What Can Rats Chew Through?

By: EarthKind

Have you ever seen an “eye-boggling” rat?

The muscles controlling a rat’s jaws are very powerful, and anchored around the eye sockets, running behind the eyeballs. When a rat grinds his teeth, his eyeballs can vibrate in and out; this usually indicates pleasure and contentment.

Rat chewing on nuts and seeds

Why Do They Need Such Powerful Jaw Muscles?

Because their incisors never stop growing! Rats have 16 teeth; four incisors in the front (two on top and two on bottom) and 12 molars (six on each side with three on top and three on bottom). Constantly gnawing on things and bruxing (repetitively grinding incisors together) wears their teeth down and helps to keep their incisors sharp. If their teeth were allowed to grow unchecked, they would grow continuously in a spiral at an 86 degree angle, making it impossible for the rat to close its mouth or eat, resulting in death. 

What Do Rats Chew On to Wear Their Teeth Down?

These pests will chew on anything that is not harder than their teeth. The Mohs Scale, developed by German mineralogist Friedrich Moh in 1812, measures the hardness of gemstones and minerals based on their ability to scratch another gemstone or mineral.  The scale ranks from 1 (softest, such as Talc) to 10 (hardest, such as Diamonds). Rat teeth rank about 5.5 on the Mohs Scale, harder than iron or copper. Human tooth enamel only ranks about 5 on the Mohs Scale. Because their teeth are so hard, rats are able to chew through most of the materials people use to keep them out, such as:

  • Plastic
  • Wood
  • Brick
  • Cement
  • Lead
  • Asbestos
  • Aluminum
  • Cinder blocks


Hard materials such as bricks, cinder blocks, and soft forms of concrete aren’t a problem for these critters. They can even get through softer metals like aluminum sheeting, lead, copper, iron, and gold. That means you shouldn’t try to keep rats out of your home with gold! Since they can chew through softer metals, they can definitely chew through even the hardest of woods. They’ll usually chew through flooring and baseboards in your home, especially where there are already smaller holes such as near pipes. Other materials they can get through include thin glass, plastic (like window & door screens and water pipes), drywall / sheetrock, asbestos, and electrical wires.

Super strong teeth are not the only superpower-like trait these rodents possess. Rats can fall 50 feet without injury; they can swim and tread water for 3 days without drowning; they can squeeze through openings the size of a quarter; they breed at an astonishing rate, rapidly populating any given area; and last but not least, their genes have mutated, making them immune to most rat poisons.

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Materials They Can’t Chew Through

Rats have the most powerful jaws of any rodent and even of many other species. Some estimates say their jaw muscles are able to exert up to 6,000 lbs. of force per square inch, which is extremely high. For comparison, a human’s jaw bite force comes in at around 70 lbs. per square inch, a hippo at 1,800 PSI, and a Nile crocodile at 5,000 PSI (see more here).

That’s a strong bite! But there are still some things rats just can’t chew through. These are materials you should keep in mind when you’re trying to keep them out of your home.

  • Solid Concrete – Rats cannot chew solid concrete. Many homes have a solid concrete foundation, so as long as there aren’t any large cracks in the concrete, these pests won’t be able to get through.
  • Stone – These rodents can’t chew through stone. That makes stone flooring and ceramic tile great materials for flooring options. Keep in mind that all ceramic tiles are not created equal. Some tiles might be weak enough for rats to chew through.
  • Hard Metals – Since rats can’t chew through hard metals like steel, it’s one of the reasons it’s recommended that holes are filled with wire mesh and steel wool and then filled with caulking. Metal tiling is also a great way to prevent them from getting into your home from the floor. Metal tiles come in many designs too, even hardwood.

How to Keep Rats Away

These critters may seem like an invincible opponent, but it is possible for homeowners to keep rats out. The first and most important step in preventing an infestation is good sanitation.  Removing food and water sources will go a long way when getting rid of rats. Store pet food and pantry goods in glass or metal containers and use a covered trash can. Keep things picked up and organized so there are fewer hiding places for rodents. Outside of the home, keep shrubbery and wood or compost piles away from the building.

The second step is to block off entry points and make the exterior of your home rodent-proof.  Even though they can chew their way through many building materials, you don’t need to leave the door open for them. Use metal screens over chimneys and dryer vents. Make sure the building’s foundation and roof soffits are well maintained.  Keep window screens in good repair and install door sweeps if there is a gap under any exterior doors. If you see rat feces, see if you can trace the droppings back to where they might be entering the building.

Lastly, protect property with a plant-based rodent repellent. These pests have poor eyesight, but an exceptional sense of smell. As a matter of fact, rats have been trained to sniff out landmines, drugs, and even to serve as rescue rats sniffing out survivors after disasters. Fresh Cab® Botanical Rodent Repellent uses essential oils that smell pleasant to humans but are offensive to rodents. The odor deters these creatures and prevents them from returning. Placing Fresh Cab pouches around your home and storage spaces will protect the areas against rats and mice.