Hammerhead has last laugh

Confirming a longheld suspicion, scientists in America have established that the creatures’ slightly forward-set eyes do have overlapping fields of vision when looking ahead, giving a binocular view.

Due to the wide spacing of the eyes, judgements of speed and distance are particularly good.

Further, because their eyes are set well out from the body, the hammerheads can see more of what is behind them by moving their heads from side to side as they swim.

And just to rub it in, the sharks have a complete, 360-degree field of vision above and below, vastly improving their ability both to spot prey and to avoid attack by larger sharks or whales.

Given all these advantages, some might wonder why there haven’t been more creatures, aquatic or terrestrial, to have evolved similarly. The movie Ice Age’s sloth, Sid, makes a good go of it, though!

The research was carried out by Dr Michelle McComb and Stephen Kajiura, of Florida Atlantic University, Boca Raton; and Prof Timothy Tricas, of the University of Hawaii, Manoa.

A number of shark species with differently shaped heads were tested in a tank. Beams of light were shone at them from various positions, and brain-reaction sensors attached to their heads recorded how they reacted.

The idea that hammerhead sharks might have binocular forward vision was put forward by sharks researcher Leonard Campagno in 1984.