The answer to whether rats can eat through plastic is a definitive yes, as these rodents possess a biological mandate to chew that makes most common plastics an inadequate barrier. Rats, mice, and other common household rodents must gnaw constantly to survive, a behavior that frequently results in property damage. The continuous growth and sheer durability of their front teeth allow them to compromise a surprising range of materials, including various polymer compounds. Understanding this gnawing imperative is the first step in properly securing belongings and excluding these persistent pests.
The Biological Imperative to Gnaw
The primary reason rats chew through objects is not always to gain access to food, but to manage the growth of their incisor teeth. Like all rodents, rats possess four specialized front teeth that are “open-rooted,” meaning they grow continuously throughout the animal’s life. These incisors can grow at an astonishing rate, sometimes as much as 2.2 to 2.8 millimeters per week.
This constant growth necessitates continuous gnawing on hard objects to wear the teeth down, preventing them from becoming dangerously long. If a rat cannot grind its incisors, the teeth can curl inward, causing painful ulcers or preventing the animal from being able to eat, leading to starvation. The teeth themselves are incredibly strong, possessing a hardness rating of 5.5 on the Mohs scale, which is harder than copper, iron, and most forms of steel.
Vulnerable Materials and Common Targets
Due to the strength and constant need to gnaw, rats can compromise nearly any material that offers a starting point, including many items made of plastic. Highly vulnerable items include thin plastic films used for food packaging and garbage bags, which offer no resistance. Thin-walled plastic storage containers, even those marketed as “heavy-duty,” can also be breached, as the plastic is soft enough for the rodent’s teeth to penetrate.
The insulation surrounding electrical wiring is a frequent and dangerous target, as the plastic or rubber sheathing is easily gnawed through, creating a significant fire hazard. Plumbing and drainage components made from softer plastics, like thin polyvinyl chloride (PVC) pipes, are also at risk, especially if a rat is seeking a water source. Rats typically exploit a seam, corner, or pre-existing flaw to begin the gnawing process.
Securing Storage and Exclusion Methods
To effectively protect stored items and prevent structural entry, it is necessary to use materials rats cannot penetrate. Plastic, regardless of its thickness, should not be relied upon for long-term food or important item storage. Instead, use containers made of thick glass or metal, such as galvanized steel bins.
For excluding rats from a home, the focus must shift to hard, dense, non-yielding materials. Rats cannot chew through materials like steel, stainless steel, or properly cured, thick concrete.
Small gaps and cracks around pipes or utility lines can be permanently sealed by tightly packing the space with stainless steel wool or copper mesh. Rats find these materials difficult to chew or pull out.
Larger entry points require the installation of durable metal barriers, such as galvanized hardware cloth or sheet metal, with mesh openings no larger than 1/4 inch to exclude rats and mice effectively. Any concrete used to patch foundation cracks should be at least two inches thick and properly mixed to ensure it is too hard for their teeth to scrape away. These durable materials are the only reliable way to create a permanent, rat-proof barrier against infestation.