Evolution over hundreds of millions of years has led to a broad diversity of animal eyes with varying degrees of complexity. Comparison of anatomical differences between the eyes of differing species can provide clues to the evolutionary origin and progression of vision. Dr. Ivan Schwab and colleagues are therefore comparing structures of the eye in evolutionary distinct animals using an ultrasound developed by Dr. Robert Zawadzki. This form of imaging allows for the viewing of the internal anatomy of the eye without harm or distress to the animal. Thanks to the California Raptor Center, the great horned owl will be included in the study and will serve as an invaluable point of comparison given the complexity of the avian eye.