I like how you mention they have an old way of intelligence, I believe that hit the nail on the head. I read a book about people passing memories onto the next generations, I think this applies strongly with snakes in an intellectual/instinctual sense. Their survival techniques have been perfected to suit them, and they pass those traits on to their young and the cycle continues. It would be like us being born with the ability to run, jump, speak, feed ourselves and socialize. Now that's an advancement!