Hammerhead Shark

Hammerhead sharks are instantly recognisable by their curious T-shaped heads. There are nine known species and each has a head of a slightly different size and shape. The hammer-shaped heads are responsible for two quite different functions.

Hammerheads have taller dorsal fins and smaller pectoral fins than most other sharks, an adaptation to bottom feeding. The shape of the head, however, offsets the loss in fin surface area. The wings of the head act as hydrofoils, similar in shape and function to the bowplanes of modern submarines. In cross-section, they have a flat underside and curved topside like a wing. They increase lift as the shark moves through the water. There is also evidence that the trailing edge of each wing behaves like the flaps on an aircraft's wing, and that these flaps can be controlled by special tube-like muscles that form part of the shark's jaw mechanism, boosting manoeuvrability. With this configuration, the hammerhead can make extremely tight turns.

The wings also spread the senses of sight, smell and electric field detection across the width of the hammer, creating a greater scanning area and improving prey detection. The eyes are widely separated at the very ends of the hammer, and the nostrils are wide apart, enabling 'stereoscopic sniffing'.