So here's a thought proposed by my old religious history professor, Prof. Walters, regarding the snake in the garden of eden.
Snakes have, in the past, been considered wise creatures. Yes, this pops up in the Biblical garden story where the snake is the (in this case malevolent) bringer of wisdom, but also in other places as well. In Hinduism Naga serpent spirits were (among other things) intelligent, wise, and divine fertility/nature spirits that are/were sometimes depicted as temple guardians. In Greek thought, the snake's relation to venom associated it with poisons, cures, herbology and medical knowledge, tying it to wisdom (as well as Asclepius' staff). Buddhism has the king of serpents, another naga-like being named Mucalinda, coming up to protect Gautama Buddha when he was meditating under the Bodhi Tree and a storm kicked up, threatening to break his meditation. Even in the Bible, Moses --who is classically depicted as being amazingly wise has a brief serpent ally when God brings his staff to life. His staff-snake eats the snakes of the priests'-- sending the message that "my God is bigger than yours," but also "I know more than you do."
It's also mentioned in the Eden story that the snake originally didn't crawl around on its belly. That was a curse God put on it after the apple incident. Before that, the snake apparently had other means of transportation; at the very least, it had the ability to climb trees, meaning it had legs. Alternatively, it might've had some other way of getting tree-to-tree. . . such as flying.
So what's another talking, serpent-like, legged-being known for being wise and (possibly) having the ability to fly? One that would've most likely been borne out of Eastern thought that traveled over to the Middle East where the Eden story takes place-- or at the very least where the Semite people who came up with it were located.
Aww yeah. The snake in the garden was totally a dragon.