The visual system of sharks: Adaptations and capability

Abstract

The visual system of elasmobranchs is reviewed with primary emphasis on recent investigations. Starting with the ocular adnexa and the whole eye and working through the cornea, uvea, ciliary zone, lens, and retina, the structure of the eye peculiar to sharks is described. Visual function as revealed by electrophysiology, photochemistry, and behavioral studies is also reviewed. The discussion ends with a description of structure and function of the elasmobranch median eye. The overall impression is that far from having poor vision, these extremely successful marine predators apparently have been provided with a high degree of visual development. While advances in our understanding of the shark eye have been impressive, much work remains, and, for example, entire areas such as resolution and spatial vision are unstudied. Probably the greatest mystery is the relation between the apparently exquisitely adapted visual system and the natural behavior of sharks. Thus what is needed is a linking hypothesis between laboratory studies of vision and the natural behavior of sharks as observed in the field. © 1977 American Society of Zoologists.