@The Cassowary It's just very backlit; if you look at the forehead/nose and a tiny portion on its lower back you can see how bright the sun reflection is from the other direction. You can also see the color line between black and brown on the front legs and the hindquarters.
I have another photo I haven't posted with different lighting and in that one you can see the reddish-brown hue much more clearly; I liked this one though because it was centered and focused on the animal.