
Scalloped hammerhead
Sphyrna lewini
The scalloped hammerhead is a coastal and pelagic shark known in the Galápagos for forming large daytime schools at Darwin and Wolf. Its numbers have fallen sharply worldwide from overfishing, and the IUCN lists it as critically endangered. The cool, nutrient-rich season draws the biggest aggregations.
Best time to see it
Largest schools gather in the cool season, roughly June to November, when the Humboldt Current brings cooler nutrient-rich water. The big aggregations are at the far-northern dive-only islands of Darwin and Wolf, reached by liveaboard rather than land-based day tours.