Fun fact, mice like to bite on low power electrical wiring because it sends pleasure impulses to their brains and make them orgasm. 
That's why mice always chew on car wiring. 

I thought the rodents find the new bio-plastics tastier than the old dino oil plastics.

Are the rest of insulation on the ribbon cables still pliable?   I had cracking on old Technic 9V cables but the whole cable would go brittle and crumble.