Firstly, let me say it is really refreshing to have a sensible debate on a topic whilst staying so polite - thank you! Tolkien was a keen debater, so he would approve, I am sure!
To the point:
Beornings are not technically a new species - they are descendents of the Edain, like other Northmen. Gandalf says of Beorn: "Some say that he is a bear descended from the great and ancient bears of the mountains that lived there before the giants came. Others say that he is a man descended from the first men who lived before Smaug or the other dragons came into this part of the world, and before the goblins came into the hills out of the North. I cannot say,
though I fancy the last is the true tale." Also, Tolkien, in letter 144, wrote: "Though a skin-changer and no doubt a bit of a magician, Beorn was a Man." Any new spider-changing bad guys created by SSG could therefore also be accepted as still being men, but with the gift of skin-changing, like the Beornings.
Radagast is described by Gandalf as "a worthy wizard, a master of shapes and changes of hue", so he may have had the power to bestow this gift.
Were there other skin-changers? Well Gandalf also says: "it is said that for many generations the men of his line had the power of taking bear's shape,
and some were grim men and bad, but most were in heart like Beorn, if less in size and strength." So not all shape-changers were of a good nature. You could therefore have evil Beornings as a concept.
There have also been other examples of shape-changing in Tolkien lore:
- Thuringwethil - a shape-changer who could take the form of a bat
- Sauron - had been known to transform into a wolf
- Beren and Luthien: "By the counsel of Huan and the arts of Luthien he was arrayed now in the hame of Draugluin, and she in the winged fell of Thuringwethil. Beren became in all things like a werewolf to look upon, save that in his eyes there shone a spirit grim indeed but clean; and horror was in his glance as he saw upon his flank a bat-like creature clinging with creased wings. Then howling under the moon he leaped down the hill, and the bat wheeled and flittered above him." There was magic here that changed their forms - Luthien could not have "flittered" had the bat just been a disguise.
So there was an "art" of skin-changing that could be learned, by various different kinds of beings. The grey area that I think we need to clear this up is: when did Beornings acquire the skill to change? Their ancestors, the Edain, didn't have the skill inherently, so where did it come from? The wizards didn't arrive in Middle-Earth until the Third Age, so if we accept SSG's interpretation, they have to have only acquired the skill no more than 2000 years before the events of the books.
So... my challenge to you is - can you prove the Beornings had the skin-changing power before TA 1000, when the wizards showed up? If so, you win the debate, my friend!
