A study in the Journal of Experimental Biology made big news late last year by beginning to answer a fundamental, fable-like question: why are hammerhead sharks shaped the way they are? The answer, as it turns out? The better to see their prey with, my dear.
The researchers found some surprising results about hammerhead vision. One of those researchers, Michelle "Mikki" McComb of Florida Atlantic University, happens to also be an enthusiastic Oceana supporter. Mikki was kind enough to answer some questions about the research:
Can you summarize the conclusions you and your colleagues reached about hammerhead vision?
The popular literature is filled with claims that hammerheads have better vision, but this was never tested. Our goal was to quantify the extent of the visual fields of hammerhead sharks in contrast to more typical head shaped sharks, in order to determine if they possessed binocular vision.
The visual field is the entire expanse of space visible around the head and can be described by one eyes field of view (monocular field), two eyes field (cyclopean) and the overlap of the two monocular fields (binocular overlap). We determined the horizontal and vertical visual fields of three hammerhead shark species as well two closely related “typical” shaped sharks.
What we found was a surprise! Hammerhead sharks do have binocular vision, and even more surprising, the extent of binocular overlaps was greater than found in the “typical” shaped sharks. The largest binocular overlap was found in the winghead shark, the hammerhead with the widest head, and is a result of the positioning of the eyes on the end of the head.