Why Do Rodents Gnaw, and What It Is Costing You
A rat does not chew through your wiring out of spite. It gnaws because its teeth never stop growing, and understanding that is the difference between setting a few traps and actually solving the problem.
17 September 2026
Most people meet the evidence before they meet the animal. A shopkeeper in Betio opens a sack of rice and finds the corner opened neatly from the inside, a guesthouse manager traces a smell to a chewed junction box above the ceiling, or a household wakes to find the plastic water pipe behind the kitchen weeping through a hole the size of a fingertip. The natural reaction is to treat the damage as vandalism, as though the animal were being destructive on purpose, and yet gnawing is not a behaviour a rat chooses in the way we choose things. It is closer to breathing, and once you understand why, a great deal of what rodents do around a property starts to make sense.
Teeth that never stop growing
A rat’s four front incisors grow continuously for its whole life, at something close to twelve centimetres a year. Nothing about that process switches off when the animal has eaten enough, so if it stopped wearing those teeth down they would curl past the point where the jaw could close, and the rat would starve with food in front of it. Gnawing is therefore maintenance, and the animal has to do it whether or not there is anything worth eating on the other side of the surface it is working on.
The teeth are also built for the job in a way that explains the damage they do. The front face of each incisor carries a band of hard enamel while the back is softer dentine, so the two wear at different rates and the tooth sharpens itself into a chisel every time the rodent uses it. That is why a rat can open galvanised sheeting, cinder block, timber door frames, soft metal pipe and almost any plastic or rubber you care to name. It is not brute strength so much as a permanently sharp edge applied patiently, night after night, at the same spot.
Gnawing is also how a rat reads a building
Teeth are the second reason. The first is that a rodent moving into an unfamiliar building has to work out where it can go, and it does that largely by testing. A gap that is too small gets widened, a seam in a wall gets probed to see whether it leads anywhere, and a cable that runs from one room to another gets followed and chewed because it passes through a hole that might be big enough to follow. Rats are also strong climbers that nest in roof spaces and trees as readily as in burrows, which is why so much of the damage on an atoll property is found overhead rather than at floor level, in ceilings, in roof timbers and in the wiring that runs between them.
Gnawing also appears to be genuinely rewarding to the animal, so a well fed rat with nothing left to widen will still gnaw, which means removing the food supply is necessary but will not on its own stop the chewing.
What it actually costs
The bill is rarely the food that was eaten. It is the sack condemned because droppings were found in it, the refrigeration unit that failed because a wire was stripped behind it, and the reputation damage when a customer sees a rat cross a restaurant floor at nine in the evening. Chewed wiring deserves the most attention, because a rodent strips the insulation without breaking the copper, leaving a live conductor resting against a timber rafter or a run of dry thatch, and in a climate as humid and as salt laden as ours that fault can sit there for months before it finds its moment.
Food premises carry an additional exposure, since evidence of rodents in a kitchen or a store is exactly what an environmental health inspection looks for, and gnaw marks on packaging are proof that does not go away when you sweep the floor.
Why a few traps rarely end it
Traps remove the rats you have caught, which is not the same as removing the population, and on an atoll the pressure from outside is constant, with rats moving along fence lines, coconut palms, cargo and the ground between neighbouring buildings. A treatment only holds if it deals with all three parts of the problem together, meaning the animals that are present, the food and water that are keeping them there, and the openings they are using to get in and out. That last part is the one most often skipped, and it is the reason a property can be cleared in March and reinfested by June.
If you are finding fresh gnaw marks, droppings or damaged stock, get in touch with Terminix Kiribati for a rodent inspection and treatment plan. Call +686 73065348 or email customercare@pestcontrol.com.ki.