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Science & Nature • Marine biology

Hammerhead Shark

Hammerhead sharks are a group of sharks in the family Sphyrnidae, known for their distinctive flattened, hammer-shaped heads called a cephalofoil.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Hammerhead sharks are a group of sharks in the family Sphyrnidae, known for their distinctive flattened, hammer-shaped heads called a cephalofoil. They are carnivorous predators that live in warm temperate and tropical waters worldwide and include several species, such as the great hammerhead and scalloped hammerhead.

Classification and species

Hammerhead sharks belong to the family Sphyrnidae. Britannica states the family includes 10 species across the genera *Sphyrna* and *Eusphyrna*.

Physical characteristics

Their most distinctive trait is the hammer-shaped cephalofoil, with eyes positioned at the outer edges of the head. This shape is associated with a wide field of vision.

Habitat and distribution

Hammerhead sharks occur in warm coastal and offshore waters in tropical and temperate regions worldwide. Some species move between shoreline habitats and deeper waters.

Diet and behavior

Hammerheads are carnivorous predators that feed on fish, squid, crustaceans, octopuses, and especially stingrays. Sources describe them as active hunters, often using their head shape to help pin prey to the seafloor.

Reproduction and conservation

Hammerhead sharks are live-bearing, with females giving birth to pups. Some species, including the scalloped hammerhead and great hammerhead, are described as critically endangered in conservation-oriented sources.

Key facts

  • Hammerhead sharks are identified by their laterally expanded head structure called a cephalofoil.
  • The family Sphyrnidae includes 10 recognized species in the genera *Sphyrna* and *Eusphyrna*.
  • They are active predators that feed on fish, squid, crustaceans, and stingrays.
  • Hammerheads are found in tropical and temperate waters around the world.
  • They give birth to live young rather than laying eggs.
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Canadian context

Hammerhead sharks are not native to Canadian waters in the same way they are to warmer tropical and temperate seas, but they are relevant to Canadian readers through marine biology, ocean conservation, aquarium education, and shark conservation coverage.

Frequently asked questions

What is a hammerhead shark?
A hammerhead shark is any shark in the family Sphyrnidae, characterized by a flattened, hammer-shaped head.
Why do hammerhead sharks have hammer-shaped heads?
Their head shape, called a cephalofoil, gives them a broad visual range and helps them locate and manipulate prey.
What do hammerhead sharks eat?
They eat fish, squid, crustaceans, octopuses, and stingrays; larger species often specialize in stingrays.
How many species of hammerhead shark are there?
Britannica identifies 10 species in the family Sphyrnidae.
Are hammerhead sharks dangerous to humans?
Attacks on humans are rare, and sources describe them as generally shy, though they should still be avoided.
Do hammerhead sharks lay eggs?
No. Hammerhead sharks give birth to live young.

References

  1. National Geographic Kids — https://kids.nationalgeographic.com/animals/fish/facts/hammerhead-shark
    Supports: Diet, lifespan, size, live-bearing reproduction, rare attacks on humans
  2. Britannica — https://www.britannica.com/animal/hammerhead-shark
    Supports: Family classification and number of species
  3. Smithsonian Ocean — https://ocean.si.edu/ocean-life/sharks-rays/great-hammerhead
    Supports: Head shape, prey, and rarity of attacks on humans
  4. Ocean Conservancy — https://www.oceanconservancy.org/wildlife-library/hammerhead-shark/
    Supports: Habitat, range, diet, lifespan, number of species
  5. Florida Museum of Natural History — https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/great-hammerhead/
    Supports: Large species, diet, and family context
  6. Britannica Kids — https://kids.britannica.com/kids/article/hammerhead-shark/639024
    Supports: Size range, habitat, diet, live young, and general behavior
  7. PADI — https://blog.padi.com/hammerhead-shark-facts/
    Supports: Conservation status of scalloped hammerhead and great hammerhead