[Image: Shark Week]
Michelle McComb from Florida Atlantic University and her research team:
“[H]ammerhead eyes, though far apart, have the greatest overlap in their fields of view. The winghead shark has a 48-degree arc in front of it that’s covered by both eyes, which must give it exceptional depth perception. By comparison, the scalloped hammerhead has a binocular overlap of 34 degrees, the bonnethead has a much smaller one of 13 degrees, and the lemon and blacknose sharks have the smallest of all with 10 and 11 degrees respectively. And that’s if the sharks swim straight ahead with their heads completely still. A hammerhead can improve its stereoscopic vision even further by rotating its eyes and sweeping its head from side to side. McComb measured these movements too by filming the sharks swimming around their tanks. Taking these movements into account, she found that the binocular overlaps of the scalloped hammerhead and bonnethead increase to a substantial 69 and 52 degrees respectively, still outclassing the 44 and 48 degree arcs of the pointy-headed species. The hammerhead species even have visual fields that overlap behind them, giving them a full 360-degree view of the world.
Read more here.