Scalloped Hammerhead (Sphyrna lewini) in the wild — Catch'Um species field guide

Scalloped Hammerhead (Sphyrna lewini) wildlife photograph

Overview

Scalloped hammerheads are instantly recognisable sharks with a broad, notched cephalofoil that spreads the eyes and nostrils wide for panoramic sensing. They often form spectacular daytime schools around seamounts and islands before hunting alone at night.

Distinct from the great white already in the catalogue, they add a second iconic shark — and urgent conservation story — for Australian, Indonesian, and US waters.

Scientific nameSphyrna lewini
Length2.5–4 m typical adults
WeightUp to ~150 kg or more
LifespanAround 20–30 years
DietFish
ConservationCritically Endangered
RegionCoastal Ocean

Habitat

Coastal ocean
Continental shelf
Seamounts

Scalloped hammerheads use warm coastal seas, continental shelves, and offshore seamounts in tropical and subtropical oceans worldwide, including waters off Australia, Indonesia, and the Americas.

Countries found

Field notes

Field scale for the Scalloped Hammerhead: length around 2.5-4 m typical adults; weight Up to ~150 kg or more. Typical lifespan: Around 20-30 years.

When you are scanning habitat, prioritise coastal ocean, continental shelf, and seamounts. Those settings are where a clean look and a usable photo are most likely.

Quick ID anchor: Shark with a broad flattened head scalloped along the front edge. Confirm with behaviour and habitat before you log the discovery.

Diet

Fish, squid, crustaceans, and rays located with widely spaced sensors on the hammer head.

Often hunt alone at night after schooling by day.

Behaviour

Form large daytime schools around seamounts and islands — a famous diver spectacle.

Migrate along coasts; use shallow nurseries for pups.

How to identify

Shark with a broad flattened head scalloped along the front edge.

Tall first dorsal fin; grey-brown above, pale below; eyes at the tips of the hammer.

Interesting facts

01
The hammer-shaped head may improve vision, prey detection, and manoeuvrability.
02
Scalloped hammerheads often school by day in large numbers.
03
They are among the most threatened large sharks due to finning.
04
Pups are born live in coastal nursery areas.
05
The 'scalloped' front edge of the head has distinctive notches.
06
They hunt fish, squid, and rays, often at night.

Conservation status

CR: Critically Endangered

Scalloped hammerheads are Critically Endangered. Targeted fishing for fins and bycatch have driven severe declines. Sanctuaries, finning bans, and protection of nursery bays are urgently needed.

Sources: IUCN Red List