Hammerhead sharks have to be one of the strangest creatures found in the ocean. While their bodies look pretty normal, their hammer-shaped heads look like they could come from science fiction or a child’s imagination.
There are nine types of hammerhead sharks described by modern marine taxonomists, which makes this one of the smallest shark families.
Every member has different characteristics and behaviors. While the common names may vary (some people even call them a mallethead shark), the scientific names and descriptions allow us to identify the different types of hammerhead sharks.
The Nine Currently Accepted Species of Hammerhead Shark
So, what are the nine species of hammerhead shark? Let’s take a look at the accepted hammerhead species. This list includes one that has only been described relatively recently as a separate shark species (the Carolina hammerhead).
We’ll also mention one additional shark that scientists now regard as not being a unique hammerhead (the whitefin hammerhead).
1. Great Hammerhead Shark (Sphyrna mokarran)
Maximum Size – 6.6 meters / 21.6 feet
Environment – Tropical and temperate waters worldwide. Coastal areas and the continental shelf.
IUCN Red List Status – The great hammerhead is listed as critically endangered with a decreasing population trend.
We start off with the largest of all hammerhead species, the great hammerhead shark. This colossal fish tends to be a solitary animal and great hammerhead can be found in coastal areas, including coral reefs and lagoons.
Great hammerhead sharks seem to prefer temperate and tropical waters, but marine biologists know very little about their reproductive, pelagic, and migratory behaviours, which may involve trips into the open ocean.
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The great hammerhead’s large cephalofoil, better known as the hammerhead, has a distinctive dent in its middle. Great hammerheads also have an especially noticeable huge dorsal fin compared to other species of hammerhead shark.
The great hammerhead shark prey on stingrays, bony fish, smaller sharks, and invertebrates, including octopus, squid, and lobsters.
Bahama Banks hammerhead sharks are particularly well known to scuba divers, with this location offering special great hammerhead trips with superb opportunities to see this magnificent creature up close.
How many great hammerhead sharks are there? There isn’t accurate global data available on the population size of the great hammerheads, but some articles suggest that there may be as few as 200 remaining.
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2. Scalloped Hammerhead Shark (Sphyrna lewini)
Maximum Size – 4.3 meters / 14 feet
Environment – Coastal pelagic species. Temperate and tropical coastal waters worldwide.
IUCN Red List Status – The critically endangered scalloped hammerhead is recorded on the Red List with a decreasing population trend.
The scalloped hammerhead shark is another of the larger hammerhead species. Scalloped hammerhead sharks are pretty easy to recognize thanks to the multiple notches in their reasonably narrow heads, which are said to look like a scallop shell.
Scalloped hammerhead sharks have a gestation period of around 12 months and produce larger litters than many other shark species.
Young scalloped hammerhead sharks have been found in estuarine waters in bays and amongst mangrove trees which they use for protection.
Adult scalloped hammerheads gather in schools made up predominantly of mature females patrol seamounts in large quantities and can often be seen swimming along thermoclines looking for a meal.
Scalloped hammerheads eat fish, including mackerel, herring, and sardines. Scalloped hammerheads are also known to enjoy pelagic octopus and squid. Especially large scalloped hammerheads have even been seen taking smaller sharks.
3. Smooth Hammerhead Shark (Sphyrna zygaena)
Maximum Size – 5 meters / 16 feet
Environment – Temperate waters and occurs worldwide at medium latitudes. Prefers inshore waters.
IUCN Red List Status – The smooth hammerhead is listed as vulnerable. Unfortunately, the population is noted as decreasing, and so it may soon be the endangered or critically endangered smooth hammerhead without action.
The second-largest hammerhead shark is the smooth hammerhead. This shark gets its name from its smooth head. Unlike the scalloped and great hammerheads, the smooth hammerhead doesn’t have any indentations in its cephalofoil.
These hammerhead sharks prefer temperate waters cooler than most other hammerheads. The smooth hammerhead will move towards the direction of poles during the summer months to stay in their desired temperatures. They will then move back towards the equator in winter.
The smooth hammerhead shark is typically found relatively close to the surface of coastal waters, including estuaries, bays, and around oceanic islands.
Smooth hammerheads enjoy eating bony fish such as herring, mackerel, and seabass. They also take smaller sharks, octopuses, squid, and crustaceans, including crabs, lobsters, and shrimps. It is believed that stingrays are a particularly favorite meal as captured smooth hammerheads are often found with the stingray’s barbs lodged in their mouths.
4. Winghead Shark (Eusphyra blochii)
Maximum Size – 1.9 meters / 6.2 feet
Environment – The tropical coastal central and western Indo-Pacific. Found in shallow waters.
IUCN Red List Status – The vulnerable winghead shark is listed as endangered. Its relatively small distribution means that it may be particularly vulnerable to local changes.
The winghead shark is also known as the slender hammerhead. It has a particularly wide head which can have a width approaching half that of the shark’s length. The winghead has a brown or gray color, a slender body, and a noticeably tall dorsal fin with a sickle shape.
The winghead shark’s head has an indentation in the front center and a small bump on either side ahead of the nostrils. It is believed that the broad head gives the winghead shark excellent vision with the most expansive field of view of any hammerhead.
Winghead sharks are also thought to have an increased ability to follow odor trails thanks to their large nostrils. It also provides a larger area for the shark’s electroreception sensors.
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The winghead is found in shallow tropical waters near the coast of the Persian Gulf and western and central Indo-Pacific.
Wingheads tend to feed along the ocean floor and eat bony fishes, cephalopods, and crustaceans.
Like the majority of sharks, wingheads give birth to live young, with each female typically producing six to 25 pups after a gestation time of eight to 11 months.
5. Bonnethead Shark (Sphyrna tiburo)
Maximum Size – 1.5 meters / 4.9 feet
Environment – Estuaries and bays. Temperate and tropical North and South American coasts.
IUCN Red List Status – The bonnethead shark is listed as endangered and extensive studies have shown that the species is regarded as largely depleted with a less than 50% chance of recovery.
The bonnethead is a small hammerhead shark with an unusually rounded front to its head. This distinctive shape has to lead to this hammerhead shark sometimes being called the shovelhead.
The bonnethead shark hammer itself is also smaller proportionally to body size than that on other hammerheads. This means that the bonnethead needs to use its pectoral fins for swimming, unique amongst hammerheads.
Also, unlike other hammerheads, there are differences in the shape between females and male bonnetheads. Males have a noticeable bulge in the center, while females have smoother round heads.
Bonnethead sharks are found on the Atlantic and Pacific coasts of North and South America. Unfortunately, they have suffered drastically from overfishing, and their numbers are significantly reduced in most areas.
Bonnetheads are known as being the only plant-eating shark, and studies have shown that their gut contents contain up to 62% of seagrass by mass. However, bonnetheads also feed on the sea bed on crustaceans, particularly blue crabs, shrimps, and small fish.
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6. Scalloped Bonnethead Shark (Sphyrna corona)
Maximum Size – 0.9 meters / 3 feet
Environment – Subtropical and tropical coast of the Eastern Pacific.
IUCN Red List Status – The scalloped bonnet is rated as critically endangered. Recent studies have shown that it may be extinct in its traditional waters around Mexico.
Next on our list is the scalloped bonnethead, sometimes known as the crown shark or mallethead shark. The head of the scalloped bonnet is a similar shape to the regular bonnethead, but it has subtle indentations.
The scalloped bonnet is the smallest hammerhead shark, and males are slightly larger when fully grown compared to females.
You might be interested to know what is the rarest hammerhead shark. The answer is likely to be the endangered scalloped bonnethead in terms of numbers worldwide.
The scalloped shark is seen in the eastern Pacific Ocean along the coast from Peru to Mexico, typically in coastal waters. Juvenile scalloped bonnethead sharks spend their youth in mangrove forest habitat and estuaries.
The favored food of the scalloped bonnet are crustaceans, cephalopods, mollusks, and fish which they will hunt along soft seabed.
In a similar way to the regular bonnethead, the numbers of scalloped bonnethead shark have been devastated in recent years by overfishing.
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7. Scoophead Shark (Sphyrna media)
Maximum Size – 1.5 meters / 5 feet
Environment – Shallow, inshore tropical waters of the Eastern Pacific, and Western Atlantic coasts.
IUCN Red List Status – The scoophead is listed as critically endangered with a decreasing population.
Of all the hammerhead shark species, the scoophead shark is one of those that is known the least about. It’s understood to be found in the tropical waters on the coast of the Eastern Pacific and Western Atlantic oceans.
The scoophead looks quite similar to the scalloped bonnethead, albeit slightly larger. On close inspection, it’s possible to see that the shark’s nose is shorter, and it has a wider arched mouth.
Scoopheads are bottom feeders and target smaller sharks, octopuses, squid, and flounders. Unfortunately for their population, scoopheads are frequently caught by individual and commercial fishers to be eaten or made into fishmeal for animal feed.
Mangrove deforestation has destroyed the nursery grounds for many animals, and marine biologists believe there has been an exceptionally high impact on the scoophead shark.
8. Smalleye Hammerhead Shark (Sphyrna tudes)
Maximum Size – 1.5 meters / 4.9 feet
Environment – Inshore, muddy waters of the eastern coast of South America.
IUCN Red List Status – The critically endangered smalleye hammerhead is regarded as having a decreasing population.
Smalleye hammerheads are sometimes called golden hammerheads or curry sharks thanks to the unique bright gold color seen on their heads and parts of their bodies which makes them easy to tell apart from other hammerhead sharks.
Scientists believe that this gold color comes from the pigment found in the shrimps that juvenile smalleye sharks eat and the sea catfish and their eggs that adults hunt. It is suggested that the smalleye hammerhead uses the color to help it stay hidden in the muddy waters that they tend to inhabit.
Smalleye sharks have the smallest eyes relative to their bodies of any hammerhead, so their name is appropriate. They have mallet-shaped heads that have a significant indentation at the middle.
It is believed that smalleye sharks give birth to about 19 pups at a time annually. Unfortunately, their limited known range off the South American eastern coast makes smalleye hammerheads especially vulnerable to extinction from overfishing and shark finning.
9. Carolina Hammerhead Shark (Sphyrna gilberti)
Maximum Size – 4.3 meters / 14 feet
Environment – Western Atlantic Ocean coast. Temperate waters.
IUCN Red List Status – Many scientists regard the critically endangered carolina hammerhead as one of the most threatened species. However, as extensive studies have not been made, this hammerhead is currently listed as unknown on the Red List.
Our last entry of types of hammerhead sharks, the Carolina hammerhead, is the one most recently discovered by science.
Carter Gilbert first recorded the Carolina hammerhead in 1967 from a specimen caught off Charleston, South Carolina. Initially, it was thought to be a scalloped hammerhead, but subsequent studies found it a separate species.
Externally, the two sharks look effectively identical. However, in 2013 Joe Quattro confirmed that the Carolina hammerhead has ten less vertebrae than a regular scalloped hammerhead shark. Genetic studies have also proven the shark to be distinctly different.
The Carolina hammer is considered to be much rarer than the scalloped shark. Little is known precisely about their distribution further than its western Atlantic Ocean roots and South Carolina birthing waters.
The Odd One Out – Whitefin Hammerhead Shark (
Sphryrna couardi/Sphyrna lewini)
Many lists of the different types of hammerhead sharks have the whitefin hammerhead shown as a separate species of hammerhead (Sphryrna couardi). However, since 1986, most scientists have recognized this shark, as in fact, being the scalloped hammerhead (Sphyrna lewini).
Sphryrna couardi does not appear in the CITES Species+ database, and the IUCN Red List redirects to the scalloped hammer.
We should note that taxonomy is a slow-moving science, and some lists maintain the original 1951 description of Sphyrna couardi.
IUCN Red List Status
As they are now considered as the same species, the “whitefin” is classed as the critically endangered scalloped hammerhead on the Red List with a decreasing population trend.
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So there you have it, there are nine types of hammerhead sharks.
All of these fascinating and iconic sharks are highly endangered. Please do what you can to promote their protection from human practices, including shark finning, overfishing, and destruction of the shark’s natural environment.