Do hammerheads with bigger heads find it harder to swim?

Science writer Liz Kalaugher analyses the unmistakable hammerhead shark.

Bogenstirn-Hammerhai, Sphyrna lewini, Arch, Darwin Island, Galapagos, Ecuador | Scalloped Hammerhead Shark, Sphyrna lewini, Arch, Darwin Island, Galapagos, Ecuador
The hammerhead's unusually shaped head may help it detect its prey from the electrical signals it gives off © Ullstein Bild / Getty

Hammerhead sharks have wide heads (known as cephalofoils) with their eyes on the ends, giving them a great range of vision. And it doesn’t seem to hamper their ability to swim.


The scalloped hammerhead, which is more than 3.5m long, has a head 120cm across, equivalent to approximately 30 per cent of its body length. Yet it swims at the same speed for its size as the more slender-skulled bonnethead hammerhead – up to 90cm long with a head that’s just 18 per cent of its body length.

Video footage of the two species has revealed that they swim in different styles to achieve the same relative speed, though.

Scalloped hammerheads, that have narrower bodies, undulate more quickly, while bonnetheads bend further from side to side. Both species waggle their heads faster than their bodies as they swim, perhaps to help them sense their prey.


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