Whether witnessing a solitary silhouette or a school of hundreds, these peculiar-headed species are the gold standard of sightings in any diver's log book. There are nine species of hammerhead shark, and although they share a similar appearance (their noggin for one), many have a different temperament and navigate different habitats. Sadly, five of these wide-eyed beauties are currently threatened to extinction. Humans are their biggest threat, despite the fact that there have only been 17 attacks in the last 450 years, none of which have been fatal. Falling coconuts, on the other hand, cause about 150 deaths annually.

Hammerheads, Cocos Island

A School To Be Reckoned With

While many sharks prefer solitude, scalloped hammerheads can be found in schools numbering multiple hundreds. They usually stay in schools during the day and separate at night to hunt, and while the exact reason is unknown, scientists speculate that it might relate to their migration patterns or mating habits.

Hammerhead profile


A hammerhead's oddly-shaped head (called a "cephalofoil") isn't just for decoration, they are equipped with sensors to help scan the seabed for food, their meal of choice being stingrays. The fortunate positioning of their eyes on the tips of their heads also gives them 360-degree binocular vision, allowing them to scan an area more quickly than other sharks. Once they find their prey, they pin them down with their heads and then eat them bite by bite.

Hammerhead, Bimini

The Reproduction Repertoire

Hammerheads are viviparous, meaning shark pups will develop while still in the uterus and feed on the placenta until they are ready to be born. A great hammerhead's gestation period generally lasts 11 months, after which she can give birth to a litter that can range anything from 12 to 40 pups. Most species will mate near the bottom of the ocean, gradually moving to the surface - except the bonnethead hammerhead, which is the only shark species capable of asexual reproduction.


Where To Find Them

Despite being the most recognisable shark to scour the sea, hammerheads are also some of the most elusive. Luckily, we know the best places to spot them. Hammerheads are found worldwide in warmer waters along coastlines and continental shelves, the best encounters being in Cocos Island in Costa Rica. You're also likely to encounter these beastly beauties in the Galapagos and Socorro, while sightings have been recorded in Indonesia and Alphonse in the Outer Islands.

"There’s nothing quite like looking up at the silhouettes of hundreds of scalloped hammerheads out in the blue. They are a circumglobal migratory species, coming together in these huge schools in areas such as Malpelo, Socorro, the Galapagos, Cocos and the Red Sea."
Eleanor Seagle, Original Diving Specialist
Hammerhead nose
In Numbers


Their average lifespan



Weight of a fully-grown hammerhead



Length of a fully-grown great hammerhead