An extreme closeup of a mule deer buck. Kind of fun image that, if you look close, showcases the horizontal pupil that deer have. That is quite different than the round ones that humans have and it gives the deer a key advantage.
With their horizontal pupils and their eyes being on the side of their head give them a 300-degree panoramic view. This is far wider than our own field of view which is less than 180 degrees and allows the deer to more easily spot threats.