The ocean is full of bizarre-looking creatures, from the rather unfortunate blob sculpin, to the adorable dumbo octopus, to the…intriguing…pacific geoduck. Perhaps the most instantly recognisable ocean oddball is the hammerhead shark. With their, frankly, ridiculous, T-shaped heads and eyes too far apart to make any sense, it’s a wonder they evolved in the first place (or didn’t die out due to morphic embarrassment). Yet they are extremely efficient, voracious predators. They are certainly deadly to their prey, but are they dangerous to us?

What Are Hammerhead Sharks?

There are actually 9 identified species of hammerhead shark (Sphyrnidae), ranging from the smallest, the 1m (3.3ft)-long bonnethead (Sphyrna tiburo), to the up to the largest greater hammerheads (Sphyrna mokarran), which can grow up to 6.1m (20ft). Hammerheads are easily recognised by their distinctively flattened, mallet-shaped heads (hence the name). This unique head shape allows them close to 360 degrees range of vision. They also have excellent binocular vision, despite their eyes being so wideset, and can see extremely well in even in low light.
In addition to their spectacular vision, hammerheads have a highly acute sense of smell, with specially formed nasal cavities which funnel water towards the sensory organs.
Like all sharks, hammerheads possess sensory organs known as ampullae of Lorenzini, which detect the electrical pulses given off by the fish they eat. These organs are located all along the hammerhead’s head, making them more sensitive than other shark species, and allowing them to detect prey even when it is buried under the sand on the sea floor.
In short, the hammerhead shark is a sensory machine. If you’re in the water, it’ll find you.
Fortunately though, hammerheads have relatively small mouths for their size, partly due to their diet. Their teeth, on the other hand, are extremely sharp and serrated, enabling them to slice through the flesh of their prey with ease.

Where Do Hammerhead Sharks Live?

Hammerhead sharks can be found in warm, tropical waters across the globe. They tend to stay close to coastlines or continental shelves, though can sometimes be found in the deep ocean, swimming close to the surface. Their preference for warm, shallow waters means they get a lot of sun exposure, and are one of the few known species which can tan!

What Do Hammerhead Sharks Eat?

Hammerheads eat a range of prey, including fish, crustaceans, stingrays, squid and other cephalopods. Larger hammerheads will also prey on other sharks. The greater hammerhead is even known to eat other members of its species, including its own offspring. In addition to its usual prey, the bonnethead shark consumes substantial amounts of seagrass, making it the only potentially omnivorous species of shark in the world.
Hammerheads detect food by swinging their heads from side in order to pick up the electrical pulses given off by their prey. They are also believed to have a very keen sense of smell.

Are Hammerhead Sharks Aggressive?

Hammerhead sharks are generally considered to be comparatively mellow sharks. Scuba divers report them as being mostly shy, sometimes curious diving companions. Hammerheads are also highly intelligent, with complex social structures and communication.
The greater hammerhead has a reputation for being the most fierce and aggressive of the hammerhead species, though many experts believe this to be an unfair assessment. Like all predators, hammerheads need to be aggressive when feeding (it’s a little difficult to hunt, kill and tear something to pieces without being at least a bit aggressive). As such, they have been known to be territorial around other sharks and spearfishers, and will sometimes snatch their fish. But on the whole, hammerheads are among the less aggressive shark species.

Hammerhead Shark Attacks On Humans

There have only been 17 (documented) unprovoked attacks by hammerhead sharks on humans since the Middle Ages (compared to the couple million hammerheads that are killed in the shark fin trade every year, this is hardly something to complain about). There has never been a single confirmed human fatality from a hammerhead shark attack. The majority of the 17 confirmed attacks resulted in fairly minor injuries to hands or feet, and were likely the result of the shark testing if that-thing-that-will-fit-in-my-mouth is edible.
At a maximum length of 6.1m (20ft) and weight of 580kg (1,280lb), greater hammerheads are certainly physically capable of seriously injuring or killing a human. The fact that there has only been one confirmed, non-fatal attack by a greater hammerhead is testament to the fact that they have no interest in doing so. That said, I’m not suggesting you go out and start trying to make friends with one. As wild predatory animals, they must be respected and admired, at a distance. Provoking any wild animal is (obviously) a terrible idea, particularly if said animal is massive and has very sharp teeth. There is (perhaps) a first time for everything…

So, How Dangerous Are Hammerhead Sharks?

Hammerhead sharks are mostly considered harmless to humans. However, like any large predator, larger hammerhead sharks are physically capable of being extremely dangerous to humans. Unlike some large predators, though, it would appear that they simply don’t want to be. This may be, in part, due to the fact that their diet consists largely of smaller, non-mammalian prey. Their anatomy and hunting style aren’t well adapted to taking down large, bulky prey, like humans, so they likely don’t see us as prey. But the same could be said for some other species of shark, which have nonetheless attacked humans far more readily. So why are there so very few attacks by hammerheads? Who knows? The reason is certainly not because they never come into contact with us. They like warm, coastal waters, just like we do. It is also not because they don’t notice us. Their incredible sensory abilities coupled with our flailing lack of grace in the water make it impossible for them to ignore us. Whatever the reason, these bizarre-looking, highly intelligent, mysterious denizens of the deep deserve our admiration far more than our fear.