Scalloped Hammerhead: The Pacific's Famous Hammer

The scalloped hammerhead is one of Costa Rica's most famous ocean animals — the wide, hammer-headed shark that gathers in great schools around remote islands like Cocos. It lives far offshore, not along our beaches, but it's a signature of the Rich Coast's Pacific. Here's what to know, plus five fun facts.

Scalloped Hammerhead · Sphyrna lewini

How to spot the scalloped hammerhead near Jacó

You won't see a hammerhead on a shallow shore snorkel near Jacó — they live around deep offshore waters and islands like Isla del Coco, a famous bucket-list dive. We include it here because it's such an iconic part of Costa Rica's Pacific. Up close, the wide, scalloped head and tall first dorsal fin are unmistakable.

5 fun facts about the scalloped hammerhead

• A head like a hammer. Its wide, flattened head spreads its eyes and sensory organs far apart, giving it a sweeping, almost 360-degree view and super-sensitive prey detection.
• Electric sixth sense. Sensors across that hammer pick up the faint electrical fields of prey hidden in the sand.
• They gather in schools. By day, scalloped hammerheads famously form large schools around seamounts and islands — a spectacular sight for offshore divers.
• A Cocos Island icon. Costa Rica's remote Isla del Coco is world-renowned for its hammerhead gatherings.
• Threatened and protected. Scalloped hammerheads are endangered from overfishing, which makes Costa Rica's protected waters vital for their survival.

The scalloped hammerhead is just one of many characters down there. See the whole cast in our Snorkel Jaco fish directory, or read real guest photos and reviews on the Snorkel Jaco reviews.