The Sphyrnidae family corresponds to a group of sharks commonly called hammerhead sharks, which have a particular head that distinguishes them from all other sharks that exist today. There are several species in this family, but this time we want to introduce you to the scalloped hammerhead shark (Sphyrna lewini).
This particular animal plays an important role within marine ecosystems, as it develops mutualistic relationships with other species, in addition to its trophic role in the marine areas it surrounds.Despite their size and the reputation that sharks generally have as aggressive animals towards humans, there are no records of hammerhead shark attacks on humans. Unfortunately, like most of these cartilaginous fish, their conversation is concerning. If you want to know more about this incredible animal, as well as the methods put in place to conserve the species, we invite you to continue reading this PlanetAnimal dossier where we will tell you all about the characteristics of the hammerhead shark.
Origin
- Africa
- America
- Asia
- Europe
- Oceania
Hammerhead shark features
The distinguishing feature of this shark, as also happens in the rest of the species with which it is directly related, is its T-shaped head.However, unlike other hammerhead sharks, the scalloped head has a rather arched head in addition to having a slit located in the central edge of this cephalic structure. Two more are located next to this main slot, giving it a scalloped appearance (wavy edges), hence its other name.
The hammerhead shark's mouth is arched and has small, slightly serrated, triangular-shaped teeth. With its head extended to the sides, its eyes and nostrils are set quite far apart. The body is relatively slender, fusiform, reaching an average of 4 meters in length and about 150 kg. The dorsal coloration is gray, while the ventral is white.
As for the dorsal fins, the first is wider and curved than the second, the pectorals are slightly rounded, which may have a darker color than the rest of the body, while the caudal is forked.
Where does the hammerhead shark live?
The hammerhead shark is widely distributed in warm temperate and tropical seas. It inhabits the pelagic areas of the coast as well as the oceanic areas. The general depth range where it travels is from the surface to around 275m, however it has been found that they can submerge to just over 1000m.
As adults, hammerhead sharks tend to be found mainly offshore, although females migrate to coastal areas during the breeding season. There are studies that indicate the entry of this species into estuarine areas. This shark moves in a variety of habitat types, so it can be found on the high seas, on continental shelves, on coral reefs, on seamounts, on coasts and in estuaries.
Habiterhead Shark Habits
The hammerhead shark can move alone, in pairs or in groups. It is common for females to swim together, while males are usually solitary and only approach these groups to breed.
This shark tends to move to areas of seamounts, coasts and estuaries at dawn. In the afternoon they move to other areas, such as coral reefs, while at night they return to the offshore pelagic fringes. This species of hammerhead shark has highly developed senses, and it is especially able to identify the electromagnetic emissions that occur in the faults of the seabed, which is why it is common to see it there.
" Younger individuals may submit to adults, while adults demonstrate control and dominance by hitting the former with their muzzle. On the other hand, the hammerhead shark tends to establish mutualistic symbiotic relationships, in particular with three families of fish: the Wrasses, the Blenniidae and the Gobiidae. These individuals allow the hammerhead shark to have no external parasites on the skin, gills and mouth.To learn more about symbiosis, see this other article: Symbiosis - Definition and Examples."
Is the hammerhead shark dangerous?
This shark has not shown aggression towards people, in fact, no attack has ever been recorded.
What does the hammerhead shark eat?
The adult hammerhead shark has a fairly varied carnivorous diet. It feeds mainly at night in open ocean waters, consuming animals such as:
- Squid
- Octopus
- Rayes.
- Cuttlefish.
- Crabs
- Shrimp.
- Lobsters
- Sea serpents.
- Little sharks.
For its part, the diet of the young hammerhead shark consists of a smaller diet, made up of a certain variety of fish that tend to hunt in shallow depths or near the coast.
In general, the hammerhead shark is an active nocturnal hunter, usually swimming behind its prey and in many cases managing to swallow it whole. Additionally, some studies indicate that, like other species of hammerhead sharks, Sphyrna lewini sometimes crushes its prey and then devours it.
Reproduction of the hammerhead shark
Males reach maturity when they reach a length of between 1.5 and 2 meters, while females do so at more when they are 2 meters. The males, which are usually alone, move towards the groups composed of females to reproduce, performing specific swims which are like a kind of courtship display to indicate their intention to reproduce. The larger, more sexually mature and more available one will withdraw from the group and, if necessary, drive other females away to eventually mate.
These animals have internal fertilization, with a placental viviparous gestation that lasts between 8 and 12 months.They have 12 to 41 offspring per breeding period, which should happen once a year or every 2 years. After baby hammerhead sharks are born, they are independent and do not receive any type of parental care. Their size at birth is between 31 and 57 cm approximately.
Conservation status of the hammerhead shark
The common hammerhead shark has been declared critically endangered by the International Union for Conservation of Nature (IUCN), with a declining population trend. This demographic drop has to do with the consumption of its meat, the use of its liver to produce oil, as well as the commercialization of cartilage and fins in various countries of the world. In addition, accidental catches in fishing nets are also a factor to be taken into account when talking about the decline of their population. These sharks have a high mortality rate once caught accidentally because although they are sometimes released, when injured they find it difficult to recover.
Among the conservation measures for the species are its inclusion in Appendix II of the Convention on International Trade in Endangered Species (CITES), as well as the ban on marketing its fins at the level international law and the obligation to carefully release individuals caught accidentally. However, greater commitments and regulations are still needed to better protect these animals.
Hammerhead Shark Pictures
