May 27, 2025, 12:23 pm | Read time: 5 minutes
A narrow gap, warm air—and just like that, a marten has found a new hiding spot. What seems like a harmless pit stop often ends with damaged cables and costly repairs. But why do these small predators love to wreak havoc in cars? PETBOOK editor and biologist Saskia Schneider has investigated this question.
Even people who don’t own a car generally know that martens can cause serious damage in the engine compartment. Every year, more than 200,000 cases of marten damage to motor vehicles are reported in Germany.1 With over 66 million registered cars in the country, this is relatively low. However, according to insurers, the financial damage amounts to more than 100 million euros annually!2 But why do martens love to chew through car cables, and how can this be prevented?
Why Martens Like to Climb into the Engine Compartment
Many think that marten damage might decrease as the animals’ natural habitat continues to shrink. But that’s not the case. Similar to foxes, martens have almost completely lost their fear of human dwellings and vehicles. As cultural followers, we increasingly find them in attics, garages, and even cars.3
But why engine compartments specifically? Martens actually love tight spaces and cavities where they can squeeze in for protection. The environment in the engine compartment perfectly matches the animals’ preferences. Additionally, it’s warm in winter if the car has just been parked.
The Reason Martens Chew Car Cables
It was once thought that the smell of warm rubber parts in the car attracted martens and that they chewed on the cables for fun. We know this behavior from other animals. Anyone who has kept rats or rabbits knows that no cable is safe from their sharp teeth.
In fact, when martens chew cables in cars, it’s not about fun or exploratory behavior. The nibbling is related to the animals’ social behavior. Looking at the times when marten damage is reported, it becomes clear that this mainly occurs from June to August. These months coincide with the animals’ mating season.
The Second Marten Becomes the Problem
Martens are solitary and defend their territories fiercely—especially during mating season. When two rivals meet, it often leads to intense fights. Therefore, martens mark their territory with a foul-smelling secretion produced in their anal glands. Primarily, this serves to ward off other martens.
Everything the marten considers “valuable” in its territory is marked, including the cozy cave in the engine compartment. So, it’s not the first marten that chews the cables. The problem arises when a second animal encounters the markings in the engine compartment.
Since we frequently move our cars and they don’t always stay in one place, there’s a chance that multiple martens will visit the engine compartment. If a marten smells a foreign fellow or, more precisely, its scent marks—it becomes so enraged that it bites around and then marks the area with its own scent. In the engine compartment, the cables and hoses are particularly affected by the animals’ “rage.” 4
Do All Martens Cause Damage to Car Cables?
In biology, “marten” actually refers to a family of dog-like predators (Canoidea). However, when we talk about martens, we generally mean the true martens (Martes). This includes the stone marten and the pine marten.
Only the stone marten causes damage to cars. While the pine marten primarily lives in forests, the stone marten is quite adaptable and flexible when it comes to choosing its habitat. It can also thrive in cities.5
Scent Marks Must Be Removed
Since marten damage occurs only after a marten has already left scent marks, it’s crucial to remove them as thoroughly as possible. This ensures that unwanted visitors don’t return, as the animals smell the foreign scent marks in the territory and want to destroy them.
Several home remedies are touted against martens, claiming to repel or deter them. These include tips like dog hair, garlic, or even toilet blocks. However, the animals quickly get used to these smells.
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How to Protect Your Car from Marten Damage
Experts therefore recommend professional marten protection for cars. These can be retrofitted in various forms available in specialty stores. They usually consist of special grids that reliably keep martens away. Additionally, corrugated tubes made of hard plastic are recommended to protect cables and hoses in the car from the martens’ sharp teeth.6
But simple behavioral rules can also help keep the car marten-free. Here are the most important ones at a glance:
- Regularly repark: This prevents a marten from perceiving your car as part of its territory.
- Leave the hood open in a closed garage: Prevents retreat into the warm space.
- Illuminate the parking space: Martens are crepuscular and nocturnal—a brightly lit parking space (e.g., with a motion detector) can deter them.
- Regularly clean the engine compartment: Scent traces from previous martens often remain. A thorough engine wash—especially after a suspected visit—removes these markings.
About the Author
Dr. Saskia Schneider holds a Ph.D. in biology. During her studies at the Free University of Berlin, she focused primarily on zoology and animal behavior. In addition to training as an editor, she completed a course in Switzerland at the Academy for Applied Animal Psychology and Animal Behavior Training, specializing in cat behavior consulting.