Scalloped Hammerhead

Overview

The Scalloped Hammerhead is a wide-ranging, coastal-pelagic shark recognized by its distinctively shaped head. It is a highly migratory species known for forming large schools, particularly in tropical and warm temperate waters around the globe.

Appearance

This species is characterized by a broad, hammer-shaped head featuring a prominent central notch and two lateral indentations along the front margin. Its body is slender and typically displays countershading, with a light grey, bronze, or olive-brown dorsal surface fading to a white underside. The tips of the pectoral fins are often dusky or black, and the lower lobe of the caudal fin may feature a dark blotch.

Distribution & habitat

Scalloped hammerheads are circumglobally distributed in tropical and warm temperate seas. They inhabit areas over continental and insular shelves, frequently moving between deep offshore waters and shallower inshore environments, including bays and estuaries. While adults often occupy deeper waters, juveniles are commonly found in coastal nursery areas.

Biology & behavior

These sharks are known for their complex social behavior, often aggregating in large schools. They are seasonally migratory, with some populations undertaking poleward movements during warmer months. They exhibit sexual dimorphism, with females generally growing larger and maturing at a greater size than males.

Feeding

Their diet is diverse, consisting primarily of bony fishes, rays, and other sharks. They also opportunistically consume various invertebrates, including squid, lobsters, shrimp, and crabs.

Reproduction

Scalloped hammerheads are viviparous, with embryos nourished by a yolk-sac placenta. They typically give birth to live young after a gestation period lasting between 8 and 12 months, with litter sizes ranging from 14 to 26 pups.