My son lives in Pittsburg...(suburban setting..)..his next door neighbor had a new Cherokee that fell prey to critters...(very expensive dealer re wiring)...my son figured he'd take a look under the hood of his "23" Ram1500...(both are DD and parked outside in the driveway)...sure enough,,,same thing...apparently there is some type of soy based material used in the wire covering that vermin enjoy