I know what critters can do; critters called RATS.
Have told before that 6 months ago I was back east for almost 2 weeks.
Came back, opened the hood, and there were seeds from palm trees (the rats ate the outside pulp) all over my valve cover, I mean covered. They must have lived there because there was also rat droppings all around the seeds.
Then they wanted desert. The desert was my speedometer cable, which they gnawed from the block bracket backward about 4 inches. Until I get another cable, I was told by a very resourceful mechanic to tie off the cable near the radiator with a plastic zip tie. It works.
If you can keep critters out, you are a good man.