Marine Biology

Hammerhead Sharks

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The silhouette of the Hammerhead shark is one of the most recognizable shapes in the entire ocean. There are nine known species of Hammerhead shark, all extremely aggressive predators. Three of the species can be dangerous to humans because of their ability to attack ferociously if provoked. In general they shy away from humans and will only fight if they feel threatened.

Reaching lengths from 3 to 20 feet, each species sports the characteristic projections on either side of its head that resemble a flattened hammer. The unique shape of the head was once believed to aid the shark in turning its body and helping it get to food with more ease, however these are not the facts. All sharks have electroreceptory sensors that detect movement in the water and potential prey. The shape of the hammerhead's head provides a much larger area for these sensors, thereby increasing the shark's efficiency in scanning for food. It is reported that the hammerhead can detect an electrical pulse of half a billionth of a volt.

The nasal tracts of the hammerhead are larger, allowing it to pick up on a the scent of a food particle ten times more efficiently than other sharks. Having a wider gap between the sensory organs also allows the hammerhead to quickly determine the difference between prey or mate. Because of their small mouth the hammerhead is generally a bottom-feeder, swimming along close to the ocean floor with its mouth open in search of food. Because their eyes are found on either side of its head the hammerhead has the widest range of vision among the sharks.

The birthing process is a physical characteristic fairly unique to hammerhead sharks. While the majority of sharks, and fish for that matter, are egg layers the hammerhead carries her young much like a mammal. Additionally, hammerheads are the only sharks capable of parthenogenesis in which a female shark can reproduce on her own with no sperm.

A fascinating fact about hammerhead sharks is their ability to tan. Only humans and pigs are known to tan in the sunlight, however hammerheads will tan if they are swimming in clear, shallow waters or stays close to the water's surface for any length of time.

Sharks, in general, are a fascinating species and the hammerhead shark is certainly one of the more intriguing ones. Aggressive, yet shy. Completely unique in form. The hammerhead shark continues to awe and inspire those who study it.

More about this author: Danielle Friedl

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