Originally trained in mathematics and art, Dr. Johnsen has studied camouflage, signaling, and non-human visual modalities for nearly 25 years. He is particularly interested in vision and camouflage in the open ocean, but also works on coastal and terrestrial species, magnetoreception, nocturnal illumination, sexual signaling, eye evolution, and human cataracts. His research combines mathematical analyses with behavioral and morphological studies and in situ measurements and observations. His field work primarily involves open-ocean research cruises that use SCUBA, specialized nets, and deep-sea submersibles.
In addition to exploring the evolution and diversity of the optical and visual tricks that animals perform, Dr. Johnsen is interested in improving communication between theoretical and experimental scientists and between scientists and artists. Outreach is a strong focus, and his research has been presented in numerous magazines, newspapers and television shows. In addition to approximately 100 research articles, he is the sole author of The Optics of Life, a coauthor of Visual Ecology. The first book is a text on optics for biologists, and the second summarizes the field of comparative animal vision. In his spare time, he is an avid nature photographer.