While on a two-hour moose scouting hike in early June, a marmot crawled up into the engine compartment of my Tacoma and hitched a ride back to the Denver metro area. Had no idea it was up there. Two days later, while taking my lab for a walk, she started going nuts near the truck. When we returned from the walk, I raised the hood and found droppings and two chewed wiring harnesses. The truck wouldn't start. I spliced some of the wires back together and got it started, and took it to the Toyota dealer. $5,500 later, it was put back together again. Luckily, my insurance covered all but the deductible. I've lived and hunted in Colorado for 27 years and had never heard of such a thing. The only difference I can think of is that I was in the mountains in June as opposed to August and later. I think if you check under the hood before you drive away from the trailhead, you should be okay.