There are many theories on what really took place in the Garden of Eden. One of my interests is this, What did the serpent look like the devil appear as. Does the word serpent mean an up right being on two legs or some other creature. How was it that Satan took on this form, and if, he could do that then can he do that now.
Another view, did he posses this serpent and the come to Eve. Did he come to her just that one time, or had he came there before?
Ge 3:14 ¶ And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life
According to the above scripture he must have been some sort of upright creature since God cast him on his belly.
Most of the other questions, any answers I would give would be conjecture.
The devil, who was Lucifer, is a spirit being (a fallen angel), and angels have not been endowed with a body of flesh nor have they been given the power to take on a fleshly form. In the Garden, Adam and Eve were spirit beings clothed upon with a body of dust (clay), but their souls (minds) were not yet corrupted with sin, nor were the animals corrupted. In this state of perfection, Adam and Eve were able to communicate with the animals in the garden: perhaps not speak to them as a person to another person, but certainly understand the animals (What? You don't speak to your pets?).
One of the devil's devices is to hide behind (camouflage) a person, animal, or thing: not necessarily possess them, literally. But people do pray to idols of wood, metal, or stone, and in effect are praying to the demons behind them. The same can be said about animals: see the lunatic from Gadarenes, with a legion of demons. As for humans, we have the scripture, "For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places." Not that most men are actually possessed, but they have allowed themselves to be influenced and manipulated by the evil spirits.
