... Living in Arizona would be better for such an issue.
I've lived here in Arizona for nearly 27 years. In all that time I've never known anyone with any issues with an animal getting into a vehicle's vent system. That doesn't mean it doesn't happen, but being an animal lover and having studied Zoology (study of animals) and Ethology (study of animal behavior), I'd make a guess that the animals here in the desert are very smart about their survival in this often changing and typically hot dry climate. We can have a 40d F swing in 24 hours - 80d F during mid-day and 40d F at night.
Gnarls.
