[RightWhale]

It's old for sure. Originally it was probably an outcropping like a yarddang, some of which are very sphinx-like naturally. The head is clearly [to me anyway] chopped down from an older head. Ihe present head is very small in proportion to the lion body. The neck also looks to be chopped away from an older sloping animal neck to make it appear more humanlike.

[poweqi]

That very well could be, when a new Pharaoh took over it's logical that he would utilize what was already there. Over time it couldn't help being chisheled away to make a new image. Some beleive that the stone was already there and cut into an image, more evidence to prove it's much older is the water marks obviously made during a much wetter time.