Hammerhead sharks, known for their distinctive, hammer-shaped heads, belong to the family Sphyrnidae. This unique head structure, called a cephalofoil, allows these sharks to sweep for prey more effectively. The cephalofoil is T-shaped, with eyes positioned at either end and a small mouth centered underneath. Most hammerhead species fall under the genus Sphyrna, while the winghead shark belongs to its own genus, Eusphyra. The cephalofoil is thought to serve several purposes, such as enhancing sensory reception, improving maneuverability, and aiding in prey capture. This specialized head structure also provides the sharks with superior binocular vision and depth perception.
The specific scientific name “zygaena” is derived from the Greek word “zygon,” which means “yoke,” possibly in reference to the shark’s distinctive head shape. The genus name “Sphyrna” is also derived from Greek, meaning “hammer,” further reinforcing the connection to the shape of the shark’s head. The hammerhead shark is one of several species within the genus Sphyrna, which also includes the bonnethead shark and the winghead shark.
Hammerhead sharks are fairly large, with some species reaching lengths of up to 20 feet. They have a broad, flat head that is adorned with an array of sensory organs, including special organs called “ampullae of Lorenzini” which allow the shark to detect the electric fields produced by other animals. This specialized head helps the Hammerhead shark to locate and catch its prey, which consists mainly of fish and invertebrates.
One of the most striking features of the Hammerhead shark is its coloring. These sharks are typically a grey or brown color on top, with a lighter underside. They have a streamlined body, with large pectoral fins that help them to swim effortlessly through the water.
Habitat
Hammerhead sharks can be found in a variety of marine environments, including coral reefs, mangroves, and estuaries. They are most commonly found in shallow waters near the coastline, but some species are also found in deeper offshore waters.
Distribution
Hammerhead sharks are found across the globe, favoring warmer waters along coastlines and continental shelves. Unlike most shark species, certain hammerhead varieties gather in large schools during the day, transitioning to solitary hunting by night.
In Australia, Hammerhead sharks can be found off the coast of Queensland, the Northern Territory, and Western Australia.
Reproduction
When it comes to reproduction, Hammerhead sharks have a relatively long gestational period, with females carrying their young for up to 22 months before giving birth. These sharks give birth to live young, with litters ranging in size from a few to over 40 pups. Hammerhead sharks reach sexual maturity at a relatively young age, with males reaching maturity at around 7 years old and females at around 9 years old.
Behaviour
Hammerhead sharks are fairly solitary animals, although they will occasionally form small groups when hunting or mating. These sharks are known to be relatively slow-moving and generally do not pose a threat to humans. However, they are known to be aggressive towards other animals, particularly when defending their territory or protecting their young.
Hammerhead Shark Attack
Hammerhead sharks are not typically aggressive towards humans and incidents of hammerhead shark attacks are very rare. However, as with any wild animal, it is important to respect their space and not provoke them.
According to the International Shark Attack File (ISAF), there have been a total of six recorded hammerhead shark attacks on humans, five of which were considered unprovoked. Of these six attacks, one was fatal. It is worth noting that the ISAF’s database includes all reported shark attacks, not just those that have been confirmed, so these numbers may not accurately reflect the true frequency of hammerhead shark attacks.
Overall, the risk of a hammerhead shark attack is very, very low, and the chances of encountering a hammerhead shark while swimming or surfing are even lower. It is important to remember that sharks play a part in the ocean ecosystem and should be treated with caution and respect, but not feared.
Conservation Status
Most, if not all, hammerhead shark species face the threat of extinction. Human activities pose the greatest danger to these sharks. Although they are often not the primary target, hammerhead sharks are frequently caught in fisheries worldwide, especially in tropical regions where they prefer the warm waters. According to the Food and Agriculture Organization of the United Nations Global Capture Production dataset, the number of hammerheads caught has risen significantly, from 75 metric tons in 1990 to 6,313 metric tons by 2010.
Shark fin traders prize hammerhead sharks for their high-quality fin needles, making them a desirable catch for the fin trade. Hong Kong, the largest market for shark fins, accounts for about 1.5% of the total annual trade. It is estimated that around 375,000 great hammerhead sharks are traded annually, equivalent to 21,000 metric tons of biomass. Unfortunately, most of these sharks are caught solely for their fins and then discarded, as their meat is generally not in high demand. However, hammerhead meat is consumed in countries like Trinidad and Tobago, Venezuela, Kenya, and Japan.
Some species of Hammerhead shark are classified as threatened or endangered due to overfishing and habitat loss. These sharks are often caught as bycatch in commercial fishing operations, and their habitats are also under threat from activities such as coastal development and pollution.
There are several efforts being made to protect and conserve Hammerhead sharks, including the establishment of marine protected areas, the implementation of fishing quotas, and the development of breeding programs. In addition, education campaigns are being carried out to raise awareness about the importance of these animals and the threats they face.
