Actually, I have mostly pythons and they do not react at all to the dogs. My thought is that dog like human is not "normal" type of food for snakes in general. The only behavior I've seen is a lot of tongue flicking & sniffing thats about all. The only aggressive behavior is one of my dogs sniffed the rat snake and the snake turned around and bit me! :shrugs:
Most of the snakes in the yard slither as fast as they can AWAY from the dog if anything dogs are seen as predators not as food, those have been my experiences. :cheers: