One of the most important predators in marine waters is the shark. There are numerous species of shark around the world. There are those who are more docile and less dangerous and there are those who are dangerous for humans and any marine species that comes close to it. In this case, we are going to talk about hammerhead shark. Its role as a predator is important because it plays a fundamental role in the control of various populations in marine ecosystems.
In this article, you will learn everything about the hammerhead shark, from its main characteristics to how it feeds and how it reproduces. We will also integrate their biology, habitat, taxonomy and conservation status. so that you have a complete and evergreen guide.
Key features
This shark is also known by other common names such as giant horned she-wolfIts scientific name is Sphyrna mokarran. It belongs to the Sphyrnidae family. Among the most striking features Of this shark, we find its T-shaped head. This is the reason this fish is known as the hammerhead shark. If we examine the entire body of this shark, we will realize that it is shaped like a hammer. The entire body could be said to be the handle by which we hold it. The T-shaped head ends up being the metal part with which we drive nails.
This T-shaped head not only gives you what has been a different visual feature. Thanks to this peculiar shape, This shark is capable of 360-degree visionAs you can imagine, these types of characteristics greatly enhance their sensory abilities and their talent for hunting and acting as predators. The shape of the head (cephalofolio) also plays a role in the maneuverability and buoyancy, allowing sharp turns without losing stability.
It is a fairly large animal with an average size of 3,5 to 4 metersIn some areas, individuals have been found measuring up to 6 meters in length. This varies greatly depending on body composition, the ecosystem in which they live, the amount of food available, their motor capacity, etc. In the great hammerhead shark (S. mokarran), the first dorsal fin is tall and falcate, a key identifying feature compared to other hammers.
Its T-shaped head helps it improve its vision and, due to its adaptation to the marine environment, it can also turn its body quickly. For an animal of such size, changing direction and sense while chasing its prey is more complicated. In this regard, its T-shaped head helps it anticipate the movements of the prey and end up changing direction and sense with greater speed. It also has a contrasting color: a grayish or greenish back and a light belly, a camouflage that conceals it when viewed from above or below.
In terms of growth and sexual maturity, differences by sex and region have been documented. Males and females reach maturity at lengths ranging from 2,1 to 2,7 m in large species, and continue to grow to over 4 m in the largest females. The size at birth is usually between 50 and 70 cm., giving hatchlings a head start in coastal environments.
Distinction from other sharks
They are really impressive animals. It is said that the White shark It is the most feared and known to all. However, the hammerhead shark has some peculiarities that make it special. They have a development of 7 senses enormously. Not only do they possess the senses we know in humans, but they have two more. One is used to distinguish frequency waves and another to detect the electric field produced by other fish. These two new senses are very useful when searching for and capturing prey. It's no use hiding behind rocks; the hammerhead shark will be able to detect them with these two highly developed senses.
The mouth of this animal is located in the lower part of the head. Its mouth is not large enough to capture large prey, but yes, he does have sharp teeth to tear better. Thanks to its sharp teeth, it has a higher capture rate with a higher probability of success. In S. mokarran, the teeth are more triangular and serrated than in S. lewini (more oblique cusps), useful for identifying species.
The color is light gray to green, allowing it to blend in with the seabed and avoid detection. The ventral part is lighter in color than the rest. This contrasting pattern means that, when viewed from below, it disappears into the bright surface, and when viewed from above, it blends in with the darker background, increasing its success as a hunter.
Compared to other hammerhead sharks, the giant S. mokarran is further distinguished by the front margin of the “hammer” almost straight, pectoral fins implanted behind the gills and a first dorsal very highThe smooth hammerhead shark (S. zygaena) prefers warmer, shallower waters, while the common hammer (S. lewini) It forms large diurnal schools and is the most common in many tropical archipelagos.
- Quick identification: broad cephalofolio, lateral eyes with nictitating membrane, 5 gill slits, first dorsal high (in S. mokarran).
- sensory system: ampullae of Lorenzini spread across the cephalofolio to detect electric fields and orient themselves with the Earth's magnetism.
- Dentition: upper and lower teeth similar, sharp and without secondary cusps; several replacement rows.
Behavior and habitat
During the day, they are often seen forming groups of quite a few individuals. When they are in large groups, they don't usually hunt much since they can't camouflage or hide. With so many individuals and their large size, it's difficult to go unnoticed among the rest of the prey. In some species, these diurnal schools exceed one hundred individuals.
At night is another story. This is where they usually have the best hunting times., since they move alone. Some specimens are more docile and harmless than others. Typically, they are more or less aggressive depending on their size. The larger hammerhead sharks have the most dangerous attacks and are more aggressive. Their life expectancy is usually around 3–4 decades in the wild, depending on accidental captures and human impact.
Regarding its habitat, although it is in danger of extinction according to IUCN data, we can find it almost all over the world. Its abundance is greater in areas whose waters are tropical and temperate. They do not prefer the cold, try to avoid it. The area of greatest activity is the one close to the coastsThe depth of the waters in which they swim is usually less than 300 m for coastal-pelagic species, although some descend to more than 270 m.
They generally swim in calm waters. Geographically, we find the largest hammerhead shark populations in the Indian Ocean, the Galapagos Islands and Costa Rica. In addition, there are key areas: the Sea of Cortez It is a mating spot; coastal mangroves of southern Belize They function as breeding grounds; and have been observed in the Bahamas and Florida site loyalty and seasonal residence. Some populations undertake long coastal and semi-oceanic migrations.
Significant movements and use of "stops" on migratory routes have been recorded, which suggests that they take advantage of ecological corridors and aggregation points for breeding, feeding, or seasonal habitat shifts. These routes increase their vulnerability to beach protection nets and coastal longlines.
Feeding and reproduction
Like most sharks, it is a carnivorous animal. The diet is mainly made up of fish, squid, eels, dolphins, crabs, snails and their favorite delicacy which are rays.
The reputation of being a great predator has been acquired due to its ability to easily capture animals. However, they do not eat humans, nor should you think you are in danger if you encounter one, a fact that explains the bond between sharks and peopleIn trophic terms, the great hammerhead shark is a apex predator opportunistic: consumes crustaceans (crabs, lobsters), cephalopods (squid, octopus), bony fish (sabalos, sardines, snappers, groupers, flatfish) and other elasmobranchs, including rays and skates.
The hammerhead shark lunges at its prey and uses his head to hit and weaken their prey. On Pacific atolls they have been observed preying exhausted grey sharks after reproductive persecutions. There are records of cannibalism, and paleontology suggests that they may have once taken advantage of juvenile megalodons when they coincided temporally and spatially.
Being more solitary animals, reproduction does not occur as often. It is a viviparous species. It reproduces every two years once it has reached sexual reproduction. The number of offspring usually varies depending on the size of the female. The gestation period usually lasts about 10 months.
Expanding: all species of hammerhead sharks are viviparous with pseudoplacenta. Embryos begin by nourishing themselves through the yolk sac, which transforms into a placenta-like structure that transfers nutrients from the mother. In S. mokarran, litters can range from 15–31 pups (with documented upper extremes), and in the hammer group births are concentrated in warm seasons and shallow coastal areas. The young are born fully formed and receive no parental care.
Taxonomy, species and detailed morphology
Scientific code name: Sphyrna mokarran (great hammerhead shark). Family: Sphyrnidae (sphinxes); class cartilaginous fish (Chondrichthyes); order Carcharhiniformes; clade Neoselachii. The family includes two genera: Sphyrna (most species) and Eusphyra (gliding horned vulture).
- Genus Eusphyra: Eusphyra blochii (horned glider).
- Genus Sphyrna:
- Sphyrna mokarran — giant hammerhead shark.
- Sphyrna lewini — common hammerhead shark.
- Sphyrna zygaena — smooth hammerhead shark.
- Sphyrna tiburo — shovelhead shark.
- Sphyrna tudes — small-eyed hammerhead shark.
- Sphyrna corona — crowned hammerhead shark.
- Sphyrna media — spoon-hammer shark.
- Sphyrna couardi — white-winged hammerhead shark.
Distinctive cranial and body features: the cephalofolio may represent 17–33% of the total length (up to 40–50% in Eusphyra). The eyes are located at the lateral ends and have nictitating membrane. The nostrils have short lobes; the nasal separation is related to the diameter of the nostrils (very wide in Sphyrna, smaller in Eusphyra). The mouth is subterminal and parabolic.
The dentition is relatively homogeneous between arches: small to moderately sized teeth, sharp and without accessory cusps. The upper jaw has 25 to 37 teeth per half of the jaw, and the lower jaw has 24 to 37, with additional posterior rows. They have five gill slits, reduced spiracle, and a moderate to very large first dorsal fin; the second dorsal and anal fins are smaller. The caudal fin is heterocercal, with developed upper lobe and shorter but functional lower lobe.
The neurocranium lacks primary supraorbital ridges; the pre- and postorbital extensions fuse to form secondary supraorbital ridges unique to the group. The vertebral centers develop wedge calcifications which stiffen the vertebrae, contributing to efficient locomotion.
Distribution, depths and population dynamics
Hammerhead sharks live mainly in areas tropical and subtropical coastal areas from all over the world and on continental shelves, island terraces and atoll passes. In S. mokarran, its range extends widely between tropical mid-latitudes, being found from the surface to over 80 m and occasionally below 200–300 m depending on the species and the area.
Some species show clear patterns: the scalloped hammer (S. lewini) It can reach depths greater than 270 m and forms massive aggregations; smooth hammerhead (S. zygaena) is a more superficial inhabitant; shovelhead (S. tiburo) It occupies turbid bays and estuaries, adapting to shallow waters. Small species tend to have more restricted distribution areas, while larger ones, such as S. mokarran, are migratory and semi-oceanic.
Breeding nuclei have been described in coastal mangroves and estuarine areas, which provide refuge for hatchlings. These “nursery” habitats are crucial for the early survival and are among the environments most threatened by human activity and environmental changes.
Conservation, threats and protection
According to the IUCN Red List, several species of hammerhead shark are classified among Vulnerable and Critically Endangered, depending on the species and region. Factors explaining their decline include high demand for fins and the impact of shark capture, high bycatch mortality and relatively low reproduction rates (biennial litters and late maturity). Long-term studies in fisheries have documented drastic population reductions in several ocean basins.
Hammerhead sharks are caught in commercial and sport fisheries using longlines, bottom nets and trawls, and are common in accidental catches in gear targeting other coastal species. Regular catches are even recorded in "beach protection" nets. At the harvest level, in addition to the fins, the meat (salted or smoked), the skin, and liver oil are used; the remains are disposed of in fish flour.
The international regulatory framework has advanced: the Sphyrnidae family has listed in CITES (regulated trade), CMS and Sharks MoU (cooperation for migratory species), the SPAW Protocol in the Caribbean, and specific protection in regional bodies such as ICCAT (retention and trade bans in certain jurisdictions). In some regions, such as Florida, there are state lists with prohibition of capture for large hammerheads. Although control gaps persist, these measures have helped stabilize some populations where management is strict.
Keys to recovery: protect coastal nurseries, strengthen control of the fin trade, reduce bycatch (mitigation devices, gear changes) and encourage citizen science and cooperation with the fishing sector for sighting and release data.
I hope that with this information you can learn more about the hammerhead shark and its main characteristics. Now you know its unique morphology, its outstanding sensory system, its diet and reproduction, the extent of its distribution and the conservation challenges that it faces. Understanding how and where it lives, what it eats, and how it reproduces is essential to appreciating its ecological role and supporting management practices that ensure its future in the oceans.
