Sharks
Scalloped hammerhead shark
Sphyrna lewini
Its hammer-shaped head, the cephalofoil, is an extraordinary biological radar, studded with electrical sensors able to detect prey buried in the sand.
🗺️ Geographic range
Temperate and tropical waters worldwide, with large gatherings off Costa Rica, Mexico and the Red Sea.
📊 Population
Global population down more than 80% over three generations according to the IUCN, mainly due to overfishing for the shark-fin trade.
⚠️ Threats
Overfishing for the fin trade
Its tendency to form large, predictable gatherings makes it an easy target for fishing destined for the fin trade.
Source: IUCN — Red List of Threatened Species
Habitat
- Pacific Ocean · Coral reef · Epipelagic zone · Feeding
- Pacific Ocean · High seas / open water · Epipelagic zone · Migration
- Red Sea · Coral reef · Epipelagic zone · Feeding
Behaviour
- Diet
- Fish, squid and rays, often flushed out from under the sand through electroreception.
- Hunting
- Sweeps the seafloor with its cephalofoil to locate prey invisible to the naked eye.
- Reproduction
- Viviparous: litters of 15 to 30 pups, fully formed at birth.
Physiology
- Anatomy
- A flattened, widened head (cephalofoil) carrying the eyes and nostrils at its tips.
- Adaptations
- Hundreds of ampullae of Lorenzini on the cephalofoil detect the faint electrical fields of hidden prey.
🔗 Web of marine life
Prey
Competitors
⚡ Its extraordinary abilities
- Ultra-sensitive electroreception via ampullae of Lorenzini spread across its cephalofoil
- Near-360° panoramic vision
🏆 Records
One of the largest schools known in a shark
Gatherings of several hundred individuals observed near certain Pacific seamounts.
Source: IUCN — Red List of Threatened Species
If you cross paths with this animal…
Risk: Low: not an aggressive species toward humans despite its impressive size.
Behaviour: Can form very large, peaceful schools near certain dive sites.
Advice: Observe from a distance, never touch or feed.
💡 Did you know?
- Can form schools of several hundred individuals near certain seamounts.
- Listed as critically endangered by the IUCN, mainly due to the fin trade.