Majestic, intelligent, fascinating, and above all, oddly shaped heads!
Many words might come to mind when you think of a hammerhead shark, but how much do you really know about them?
We’re going to start by answering what is a hammerhead shark with some basics. Then, we will let you in on some fascinating hammerhead shark facts that might surprise you.
Some Frequently Asked Hammerhead Shark Questions
Let’s start at the beginning and find out who is the hammerhead shark.
Do Hammerhead Sharks Still Exist?
Absolutely! Yes, hammerhead sharks still exist. You’ll find them in many of the world’s oceans, and as we will see, they come in a range of different sizes. Although hammerheads share many common characteristics, some species exhibit unique qualities.
What Does a Hammerhead Shark Look Like?
Hammerheads sharks look a lot like any other typical shark, except for one noticeable and exceptional feature. Their heads have a tee, or flattened hammer-like shape called a cephalofoil.
Most hammerhead sharks are gray or olive green on top, while they have striped or white bellies to provide camouflage from any predators approaching from below.
Proportional to their body size, hammerheads have smaller mouths than other shark species of similar size.
How Many Hammerhead Species Are There?
There are nine species of hammerhead sharks described by modern marine taxonomists, which makes this one of the smallest shark families.
You can check out our informative article on “How Many Types of Hammerhead Sharks Are There?” to get details on all nine species.
What Is the Scientific Name for a Hammerhead Shark?
Hammerheads sharks make up the family Sphyrnidae in the order Carcharhiniformes.
Inside the Sphyrnidae family, there are two genera. Most hammerheads are in the genus Sphyrna. Just one, the winghead shark, is in the genus Eusphyra.
The complete list of hammerhead shark species scientific names is as follows:
1. Great Hammerhead Shark (Sphyrna mokarran)
2. Scalloped Hammerhead Shark (Sphyrna lewini)
3. Smooth Hammerhead Shark (Sphyrna zygaena)
4. Winghead Shark (Eusphyra blochii)
5. Bonnethead Shark (Sphyrna tiburo)
6. Scalloped Bonnethead Shark (Sphyrna corona)
7. Scoophead Shark (Sphyrna media)
9. Carolina Hammerhead Shark (Sphyrna gilberti)
Where Do Hammerhead Sharks Live?
Hammerhead sharks live in temperate and tropical waters all around the world. They are almost always seen near the coastline, living along the continental shelves.
While most hammerheads live close to the coast, colonies can be found many miles from the mainland living around seamount reefs. Scuba divers see hammerhead sharks in such places as Daedalus Reef, located about 50 miles / 80 kilometers out in the Egyptian Red Sea.
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Hammerheads are not keen on water that’s too warm, so they will migrate to cooler waters either deeper or further from the equator in the summer. In years with El Niño conditions, hammerheads may be found hundreds of miles further than expected, seeking sufficiently comfortable temperatures.
How Many Teeth Does a Hammerhead Shark Have?
If you’re wondering, “would a hammerhead shark eat a human?” you might want to know how many teeth one has. We’ll look at why hammerheads don’t pose a real threat to humans later.
Different hammerhead species vary significantly in size and naturally have different teeth numbers.
The largest hammer, the great hammerhead, has triangular, serrated teeth.
Great hammerheads have about 37 teeth in their upper and lower jaws for each series.
These are presented as 17 tooth rows on each side of the upper jaw, with two or three teeth in the center. The lower jaw has 16 or 17 teeth on each side and between one and three in the middle.
While the larger hammerheads have sharp jagged teeth, smaller species, including the bonnethead, have flatter teeth to crush their food.
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How Do Hammerhead Sharks Reproduce?
Most hammerhead sharks reproduce a maximum of once a year. The male shark will bite the female as part of a courtship ritual until she accepts him as her mate. Fertilization occurs internally as the male transfers sperm to the female using his claspers.
Female hammerheads are viviparous and give birth to live young. Some species only have two, but typically hammerheads have 12 or 15 pups. The largest species, the great hammerhead, can have up to 40.
17 Fascinating Hammerhead Shark Facts
1. The Head Shape Gives the Hammerhead Enhanced Sense Powers
What do hammerhead sharks use their unusual hammer-shaped heads for?
Scientists think the hammer-shaped head spreads the ampullae of Lorenzini, the electrical sensory organs, far wider and over a greater surface area than regular sharks. This gives hammerheads an enhanced ability to find prey beyond visual range.
Many hammerhead sharks enjoy eating food buried in the sand, including stingrays. The widely spread enlarged electrical sensory organs let them discover hidden meals they otherwise might miss.
The hammerhead’s nostrils are also larger and longer than regular sharks giving them the increased capacity to detect odors in the water.
2. The Hammer Also Enhances Eyesight
Another answer to the question, “Why does a hammerhead shark have a hammerhead?” is because it gives them better eyesight.
A hammerhead’s eyes are located right on the ends of its hammer. You might think this restricts their vision, but it gives them superior underwater sight.
Scientists studying hammerheads have discovered that they have superior depth perception that covers almost 360 degrees compared to other sharks. This prowess is valuable when it comes to hunting food or avoiding predators.
The wider spread eyes mean that hammerheads may have a small blind spot at the tip of their snouts, but the sharks’ characteristic sweeping swimming motion can easily compensate.
3. Hammerheads Have Larger Than Average Brains
So, are hammerhead sharks smart? They have larger than average brains for their body size compared to other sharks. This might be due to all the extra information their electrical sense organs and eyes feed them. Luckily there’s plenty of space available in their cephalofoil.
4. The Great Hammerhead Shark Is the Largest Hammer (And Many Other Species Are Much Smaller)
What Is the Biggest Hammerhead Shark Ever Caught?
The biggest hammerhead ever caught was a great hammerhead shark that measured 6.6 meters / 21.6 feet in length.
How Big Is a Hammerhead Shark?
While the great hammerhead shark is the largest, most other hammerheads are smaller.
The smallest hammerhead is the scalloped bonnethead which only grows to about 0.9 meters / 3 feet.
The more common scalloped hammerhead grows to a maximum of 4.3 meters / 14 feet.
How Much Does a Hammerhead Shark Weigh?
The heaviest great hammerhead shark ever caught was a female who weighed 580 kilograms / 1,280 pounds. Her extreme weight was because she was carrying 55 pups.
The smaller hammerheads can weigh between 6 and 400 kilograms / 13 to 880 pounds depending on the species.
5. The Winghead Has the Widest Head (And It Might Be the Original Hammerhead)
Also known as the slender hammerhead, the winghead has a particularly wide head. It can be equivalent to half the shark’s total length.
It’s unknown why the winghead has such a wide hammer. However, scientists believe that the winghead may be the one species of original hammerhead from which others have evolved.
This suggests that the earliest hammerhead sharks probably all had larger hammers. You can assume that the resulting extra-long nostrils and large electro sensors give the winghead even more extraordinary sensing abilities. However, other species may have given this up for increased maneuverability in the water.
6. The Great Hammerhead Shark Uses Its Head To Trap Stingrays
When hunting its favorite stingray meal, the great hammerhead shark will use its shovel-shaped head to trap the creature against the bottom before inflicting immobilizing bites to the ray’s wings.
Unfortunately for the stingrays, the sharks don’t seem concerned by their barbs. Indeed, great hammerhead sharks are often found, seemingly entirely unbothered, with stingray barbs sticking out of their bodies or mouths.
7. Hammerhead Sharks Are Not Especially Dangerous
Hammerhead sharks are not particularly dangerous to people despite their sometimes fearsome appearance.
Do Hammerhead Sharks Attack People?
The International Shark Attack File records only 17 unprovoked attacks on humans caused by hammerhead sharks since their records began in 1580.
Like any wild animal, a hammerhead shark can be dangerous, but they certainly don’t actively hunt people, and a hammerhead has never caused a recorded fatality.
Are Hammerhead Sharks Friendly?
Friendly might be overstating it, but hammerhead sharks can be curious and show intelligence underwater.
Scuba divers often observe a lone hammerhead shark sent as a sentinel from beyond their view to see what they are up to in the water. It is then quite common for the lone shark to be joined by others once they’ve noticed that the divers don’t present a danger.
8. There’s a Hammerhead That Eats Seagrass
What Do Hammerhead Sharks Eat?
Hammerheads eat fish, squid, crustaceans, and even octopuses. The larger sharks will eat smaller sharks and stingrays, and the great hammerhead shark is known to be cannibalistic.
Bonnetheads are the only plant-eating shark. Scientists studying the contents of the bonnethead’s guts have found it to contain up to 62% of seagrass by mass.
However, these hammerheads also scour the sea bed for crustaceans, particularly blue crabs, shrimps, and small fish, to supplement their vegetarian meals.
9. One Hammerhead is Gold
What Color Is a Hammerhead Shark?
The standard color for hammerhead sharks is gray or green on top, with a white or striped belly.
However, the smalleye hammerhead has a unique gold color that has led them also to be known as curry sharks or golden hammerheads.
It is believed that the smalleye use this coloration to hide in the muddy waters they like to inhabit. The color comes from a pigment in the shrimps and sea catfish that smalleye hammerheads enjoy eating.
10. Hammerheads Are Often Eaten by Other Sharks
What Eats a Hammerhead Shark?
Larger sharks, including great white sharks and tiger sharks, often feed on hammerhead species. The great hammerhead shark will also eat other sharks and has been observed eating smaller sharks of its species and even their own young.
Killer whales are also known to enjoy a hammerhead meal given the opportunity.
However, by far, the biggest killer of hammerhead species is humans. Hammerheads killed for shark fins, liver oil, meat, or skins have significantly impacted wild populations and are pushing many species to extinction.
11. Hammerheads Can Be Seen in Some Large Public Aquariums
If you’re wondering, “can hammerhead sharks live and survive in captivity?” Yes, in some cases, they can.
The smaller species of hammerhead can be seen in public aquariums. The small bonnethead, for example, has lived and even bred in several aquariums.
However, the larger hammerhead sharks are considerably more challenging to keep alive in captivity. Not only do these sharks grow bigger, but their behavior makes them entirely unsuitable for even the most extensive public aquarium.
Some public aquariums have displayed scalloped, smooth, and even great hammerhead sharks. However, they typically do not thrive and sadly have very limited lives.
12. Hammerheads Evolved Quite Recently
So, how did the hammerhead shark evolve? Scientists at the University of Colorado discovered that hammerhead sharks as we know them today began to diversify about 20 million years ago.
This makes hammerhead sharks relatively recent additions to the ocean’s wildlife compared to more regular sharks who have existed for about 420 million years.
13. Hammerheads Like To Swim on Their Sides
Scientists believe that hammerhead sharks often swim on their sides as it allows them to swim more efficiently by reducing drag.
A study fixed cameras to several great hammerheads and found that they spent up to 90 percent of the time swimming at an angle.
It may also be that the angular swimming enables the hammerhead to take maximum advantage of its wide field of vision and literally keep a watch both above and below.
14. Hammerheads Often Travel in Packs
Scalloped and smooth hammerheads prefer to school in large numbers, and most famously, divers can observe groups of many hundreds in the waters of the Galapagos Islands.
Typically fish, including juvenile sharks, will school together for protection. However, the fully-grown hammerheads have very few natural predators, and it is not known why they stay in groups as adults.
One theory is that the sharks may act in smaller groups to identify potential food sources. However, the groups seem to scatter at night when most hunting occurs. Larger groups may be part of mating routines or migration patterns.
15. Young Scalloped Hammerheads Can Suntan
Young scalloped hammerheads spend their time in shallow waters of lagoons, estuaries, and mangrove swamps. This exposes them to intense sunlight, and they have evolved an incredible way to avoid sunburn and prevent skin cancer.
Scientists studying baby sharks in very shallow water found that their skins produced significant amounts of melanin which turned them a dark brown color.
16. Hawaiians Believe the Hammerhead Watches and Protects Them
Native Hawaiian culture believes that some sharks are sea gods called an aumakua who protect humans.
The hammerhead, known as mano kihikihi, is not considered a man-eater. Instead, it is the birth animal called aumakua given as a sign for those meant to be warriors who travel the seas.
Non-niuhi sharks (those who aren’t man-eaters) are believed to be reincarnated family members.
Although sightings are rare, they signify good luck, and that gods are protecting families when a hammerhead is seen in Hawaii.
17. Hammerhead Sharks are Endangered
Sadly all species of hammerhead sharks are endangered to some degree. Four species are listed as critically endangered on the IUCN Red List which records animal species conservation status and population changes. The remainder are regarded as endangered or, at best, vulnerable.
It is vital that governments urgently bring in proactive legislation to enforce the protection of these and many other ocean animals before it is too late.
So there you have it, our list of fascinating hammerhead shark facts.
Which did you find the most surprising? Let us know in the comments below. Are there any incredible tit-bits that we forgot? If you know anything we’ve missed, make that a comment too!
British-born Dan has been a scuba instructor and guide in Egypt's Red Sea since 2010.
Dan loves inspiring safe, fun, and environmentally responsible diving and particularly enjoys the opportunity to dive with sharks or investigate local shipwrecks.
When not spending time underwater, Dan can usually be found biking and hiking in Sharm's desert surroundings.