Tolkien's aim for his series was to create a historical mythology for Britain (on a par with the Edda and the Suomi myth-cycles), and he meant for Middle Earth to be seen as part of the history of our world - some time in the remote past. Watching The Two Towers I realised that this was something that Peter Jackson and the folks at Weta Digital had seized upon, and in a rather amusing way.
Take a look at the film depiction of the wargs. Not particularly wolflike, but if you take a trip to a museum or read a book on prehistoric mammals you'll see certain similarities with the amphicyon (also known as the "bear-dog"). Neither bear, nor dog, the grizzly bear-sized predator was a major predator in both Europe and the Americas.Then there was the oliphaunt, this time not treated as an elephant, but as a four-tusked mastodon - probably a species of trilophodon or similar. All creatures that lived millions of years ago, when history would have been lost in the fossil record, and scoured from the world by glaciers. A nice way of showing Tolkien's world was linked to ours, but lost in time and myth.
Of course, I'm now even more sure that there's another sprawling saga for the folks at Wingnut to film: Julian May's Saga Of The Exiles.