Main Content
Hammerheads are aggressive hunters, feeding on smaller fish, octopuses, squid, and crustaceans. They do not actively seek out human prey, but are very defensive and will attack when provoked.
Photograph by Brian J. Skerry
Map
Hammerhead Shark Range
Fast Facts
- Type:
- Fish
- Diet:
- Carnivore
- Average life span in the wild:
- 20 to 30 years
- Size:
- 13 to 20 ft (4 to 6 m)
- Weight:
- 500 to 1,000 lbs (230 to 450 kg)
- Group name:
- School or shoal
- Did you know?
- Hammerheads use their wide heads to attack stingrays, pinning the winged fish against the sea floor.
- Size relative to a 6-ft (2-m) man:
-
Hammerhead sharks are consummate predators that use their oddly shaped heads to improve their ability to find prey. Their wide-set eyes give them a better visual range than most other sharks. And by spreading their highly specialized sensory organs over their wide, mallet-shaped head, they can more thoroughly scan the ocean for food.
One group of sensory organs is the ampullae of Lorenzini, which allows sharks to detect, among other things, the electrical fields created by prey animals. The hammerhead's increased ampullae sensitivity allows it to find its favorite meal, stingrays, which usually bury themselves under the sand.
The great hammerhead is the largest of the nine identified species of this shark. It can grow up to 20 feet (6 meters) in length and weigh up to 1,000 pounds (450 kg), although smaller sizes are more common.
Found in temperate and tropical waters worldwide, far offshore and near shorelines, hammerheads are often seen in mass summer migrations seeking cooler water. They are gray-brown to olive-green on top with off-white undersides, and they have heavily serrated, triangular teeth. Their extra-tall, pointed dorsal fins are easily identifiable.
Most hammerhead species are fairly small and are considered harmless to humans. However, the great hammerhead's enormous size and fierceness make it potentially dangerous, though few attacks have been recorded.
Hammerhead populations are not accurately known, but appear stable worldwide, and they are not considered threatened.
Related Galleries
Shark Features
-
Sharks
Learn all you wanted to know about sharks with videos, quizzes, puzzles, and more.
-
An Uneasy Eden
Discover a pristine reef where sharks reign supreme in this National Geographic magazine feature.
-
See What's Inside
Find out what makes the great white shark the largest predatory fish on Earth with this interactive feature from NGC's Great White Odyssey.
-
Shark Attack
Would you survive a shark attack? Watch the survival guide video to learn more.
-
Courting Sharks
Learn more about what National Geographic/Waitt grantee Nick Whitney is doing to identify mating behavior in adult nurse sharks during their mating season in the Florida Keys.
Advertisement
Special Ad Section
-
Audio Slideshow
Take a photographic journey through Montana and hear Annie Griffiths Belt's narrative.
-
Adventure Videos
Check out adventure videos and go "Behind the Lens."
Shop Animals and Nature
-
Animal & Nature DVDs
Shop our store for a wide collection of animal, wildlife, and nature DVDs.
-
2010 Animal & Nature Calendars
Featuring stunning National Geographic photography, calendars make great gifts.
Blogs
-
NatGeo NewsWatch
Keep current on developments in science, nature, and cultures.
-
Dog Whisperer
Get the inside story as Cesar Millan helps problem dogs and their owners.
-
BlogWild
National Geographic explorers share tales (and photos) of their adventures.