People often think of Hammerhead Sharks as one single species. However, there are ten different types of Hammerhead Sharks, each with unique biology and behaviors. Here is a guide to all nine different types of Hammerhead Sharks and what makes them different than other Hammerheads. These Hammerhead Shark facts are essential to understanding the full diversity of the species and can help you identify the different types of Hammerheads.
1. Bonnethead Shark: Found along the Northern South American coast, Southern California coast, and in the Gulf of Mexico, Bonnethead Sharks have a broad, smooth, spade-like head. Bonnethead Sharks are a smaller species of Hammerhead Sharks only grow to an average of 2–3 ft (0.61–0.91 m) in length. Bonnetheads are really unique because they are the only shark that is sexually dimorphic. The male and the female of the species have very different biological traits. The females have a very broad, round head, while the males have a distinctive bump in the center of their hammer.
2. Carolina Hammerhead: The Carolina Hammerhead was only discovered in 2013, so very little is known about this species. They were initially grouped with the Scalloped Hammerhead as the same species, but scientific study showed that they actually have ten fewer vertebrae than the Scalloped Hammerhead, so they are a different species. They share a lot of the same biological traits and the Scalloped Hammerhead, but until further research is conducted on the species, we don’t know the full extent of the differences.
3. Great Hammerhead: The Great Hammerhead is the largest of the Hammerhead Sharks and is found all over the world in tropical and subtropical waters. They grow an average of 11 ft (3.5 m) and weigh over 510 lb (230 kg), though females can often grow much larger. They also have the largest hammerhead, measuring 23-27% of their total body length. Their hammerhead is also unique because it the front edge is completely straight. They compensate for their giant heads but swimming on their sides, known as “rolled swimming.” This reduces the drag against their heads and allows them to swim much faster through the water.
4. Scalloped Bonnethead: The Scalloped Bonnethead is probably the rarest of the Hammerhead Shark species. They are found in tropical and subtropical waters in the Western Hemisphere and often hunt in mangroves and estuaries. They are also perhaps the smallest species of Hammerhead Shark measuring only 3 ft (92 cm) in total length. They have a rounded, scoop shaped head with bonnet-like ridges, leading to their name.
5. Scalloped Hammerhead: The Scalloped Hammerhead has a broad migratory range and can be found on the coastlines of every continent besides Antarctica. Scalloped Hammerheads are known for their very complex social behaviors. They tend to swim in large schools numbering well into the hundreds. They have a vertical schooling hierarchy where the youngest pups swim near the surface while the largest adults swim near the seafloor. The males and females vary greatly in size with the males measuring an average of 4.9-5.9 ft (1.5-1.8 m) and the females averaging 8.2 ft (2.5 m) in length. Their hammerheads have a scalloped edge which is where they get their unique name.
6. Scoophead: The Scoophead Shark is another rare species of Hammerhead Shark found in the tropical waters in South America. Scoophead sharks grow to 3.2-4.36 ft (100-133 cm) at maturity. They have a very unique head that is broad and mallet shaped that measures 22-33% the total length of their bodies. They front of their hammerhead is arched and contains no ridges. The Scoophead coexists with two other species of sharks in the Caribbean but they do not tend to compete for resources or territory.
7. Smalleye Hammerhead: The Smalleye Hammerhead, also known as the Golden Hammerhead, lives along the Eastern coast of South America. Smalleye Hammerheads are a smaller species of Hammerhead Shark and only measure 3.9-4.3 ft (1.2-1.3 m) in total length at maturity. They have a very unusual golden brown coloring with a yellow metallic, iridescent sheen that looks like gold. This bright golden color fades as they grow older. The Smalleye Hammerhead’s head only tend to measure around 26% of their total body length, so they have some of the smallest hammerhead proportions.
8. Smooth Hammerhead: The Smooth Hammerhead is the most cold tolerant of all Hammerhead Shark species and will migrate from tropical and subtropical waters into temperate zones. The Smooth Hammerhead is the second largest species of Hammerhead Shark growing between 8.2-11.5 ft (2.5-3.5 m) at maturity. Their hammerhead is flat and very rounded in the front. Unlike the Scalloped Hammerheads they do not have ridges along the front edge, but their hammers are very smooth. Unlike other species of Hammerhead, they tend to also be very solitary and only swimming in groups during mating season.
9. Winghead Shark: The Winghead Shark is probably the most unique of all Hammerhead Sharks. First of all, it has its own subclass of sharks that evolved separately from a different family branch of sharks. Secondly, it found primarily in Southeast Asia and along the Northern Australian coastline. The Winghead Shark has two segments in its hammerhead, that look similar to wings. The total cumulative length of these measure anywhere from 40-50% of the total body length of the shark. They are very narrow and sweep backwards and have an indentation in the center. The Winghead Shark grows to 6.2 ft (1.9 m) in length at maturity.
These nine species of Hammerhead Sharks show that even in a very narrowly defined species of shark there is a wealth of biological diversity. Hammerhead Sharks range in size, distribution, and even have vastly different types of Hammerheads. Understanding these Hammerhead Shark facts, helps us understand how varied all the different species of sharks are around the world. So next time you are studying Hammerhead Sharks, make sure you know which of the nine types you are learning about!