Chordata · chordates
Great hammerhead
Sphyrna mokarran
Sphyrnidae · hammerhead sharksIUCN: Critically Endangered

The largest hammerhead, with a tall, sickle-shaped dorsal fin.
Fun factIt pins stingrays to the seafloor with its head.
- Waters
- Worldwide
- Depth zone
- Coastal shallows & estuaries, Coral reefs
- Diet
- Stingrays & other sharks
- Size
- Up to 6 m
Classification
Chordata › Chondrichthyes › Carcharhiniformes › Sphyrnidae
- Kingdom Animalia animals
- Many-celled organisms that eat other living things for energy (heterotrophs)
- Cells have no cell walls
- Most can move at some stage of life
- Clade Bilateria bilateral animals
- Body has a left and right side that mirror each other (bilateral symmetry)
- Head end with concentrated nerves; three tissue layers
- Includes about 99% of all living animal species
- Clade Deuterostomia deuterostomes
- In the embryo, the first opening becomes the anus and the mouth forms second
- Includes echinoderms and chordates
- Phylum Chordata chordates
- At some stage of life: a stiffening rod along the back (notochord)
- A hollow nerve cord along the back (dorsal)
- Slits in the throat (pharyngeal slits) and a tail past the anus
- Subphylum Vertebrata vertebrates
- A skull (cranium) protecting a brain
- Backbone or similar support around the nerve cord
- Includes fishes, amphibians, reptiles, birds, and mammals
- Infraphylum Gnathostomata jawed vertebrates
- Jawed vertebrates: jaws formed from gill arches
- Paired fins or limbs
- Includes all fishes except hagfish and lampreys, plus all tetrapods
- Class Chondrichthyes cartilaginous fishes
- Skeleton made of cartilage, not bone
- Skin covered in tooth-like scales (denticles)
- Teeth constantly replaced; males have claspers for mating
- Subclass Elasmobranchii sharks & rays
- Sharks and rays: five to seven separate gill slits on each side
- Many rows of replaceable teeth
- Clade Selachii sharks
- Sharks: gill slits on the sides of the head
- Pectoral fins not joined to the head
- Superorder Galeomorphii galeomorph sharks
- Sharks with an anal fin and five gill slits
- Includes most familiar sharks
- Order Carcharhiniformes ground sharks
- Ground sharks: lower eyelid (nictitating membrane) that closes over the eye
- Anal fin and two dorsal fins
- The largest shark order
- Family Sphyrnidae hammerhead sharks
- Hammerheads: head flattened into a wide 'hammer' (cephalofoil)
- Genus Sphyrna
- Species in the same genus are very close relatives and often look alike.
- Species Sphyrna mokarran Great hammerhead
Closest relatives in the guide
- Scalloped hammerhead Sphyrna lewini same genus
- Smooth hammerhead Sphyrna zygaena same genus
- Atlantic sharpnose shark Rhizoprionodon terraenovae same order
- Blue shark Prionace glauca same order
- Bull shark Carcharhinus leucas same order
- Dusky shark Carcharhinus obscurus same order
- Oceanic whitetip shark Carcharhinus longimanus same order
- Sandbar shark Carcharhinus plumbeus same order