These are the mustangs that live on Pryor Mountain, in the Wild Horse Refuge. Cloud, Boulder, Red Raven and others were made famous by Ginger Kathren and her documentary on his life featured on 'Nature'.
I got to the McCullough Peaks area before sunrise, and as the eastern sky started to color up, a band of mustangs began walking along this ridge. Even in silhouette, you can see that her mane is tangled and twisted into dreadlocks.