Some truck or should I say vans that make express delivery have AC, around here we went from regular trucks with no AC to nice vans with AC.

Sadly it's not uncommon, those drivers have to hurry all day so anything that is to be signed for is usually a "knock once and run", which is why I never require signature, all it takes is for the person to go to the bathroom and miss the driver.

When the package does not require signature it is dropped off at the door.

Usually snakes are fine even when delayed (I have my fair share of animals delayed for 24 hours and they have all made it without issue), it mainly depends on how the animal is packed and the temperature in the truck or van (outside temps does not mean that this will be the temp in the vehicle.)