Update: 13th November 12:00 GMT Add at the bottom a comparison of a real Polar Bear Skull and the one shown in the promo.
Update: 13th November 10:00 GMT I've just added improved quality screenshots and video.
Thanks to Lyly for obtaining the video for us. Our first real look at the Season 4 promo.
For those wanting to compare the skull shown in the promo with that of a polar bear here you go.