This article is 15 Amazing Fun Facts (and one not so Fun Fact) About Hammerhead Sharks.
Family: Sphyrnidae
FACT #1 Their Head Shape Is A Cephalofoil.
The term Cephalofoil refers to the distinctive hammer-shaped head of this species of animal. We don’t fully understand why their heads evolved this way, but theories suggest that it enhances their vision, maneuverability, and electroreception. Put more simply it enables them to catch prey more easily.
FACT #2 Hammerhead Sharks have 360 Degree Vision
Hammerhead Sharks have the most complete vision of any of the shark species. The positioning of their eyes allows them to see 360 degrees all around them. This means they can simultaneously see what’s happening above and below them. There is a downside to this incredible capability, though; there is a blind spot right in front of the nose. It appears that small fish have fathomed this out, too, as they often congregate in this exact spot.
FACT #3 They Are Hammerheads In Name And By Nature
Hammerheads ram sting rays and pin them down into the substrate using their heads. We assume this acts to tire their prey out so that they can eat it quickly before moving on to their next victim!
FACT #4 There Are Multiple Species Of Hammerheads
When people think of Hammerhead Sharks, most often they are visualizing the Great Hammerhead Shark. There are currently 10 species of Hammerhead identified. You never know, there might even be more out there!
- Great Hammerhead
- Scalloped Bonnethead
- Smooth Hammerhead
- Whitefin Hammerhead
- Scoophead
- Bonnethead
- Smalleye Hammerhead
- Winghead Shark
- Scalloped Hammerhead
- Carolina Hammerhead
FACT #5 Hammerhead Sharks Are Voracious Predators
They are most famous for their love of stingrays, but hammerhead sharks have a varied diet including octopus and squid. They eat different fish, for example, hake & skate, and they will also tackle mammals such as the dolphin. Reptiles are also on the menu, such as the sea snake, as are crustaceans such as the crab. If this wasn’t enough, the Smooth Hammerhead has a reputation as a cannibal!
FACT #6 Bonnetheads Are Omnivores
The Bonnethead leads a more peaceful life than its cousins. It’s an omnivore and spends its time eating seagrass as well as crustaceans!
FACT #7 Hammerhead Sharks Appear Unaffected by Stingray Barbs
It’s probably a good job since stingrays are one of their favorite food. The barbs of stingrays are pretty nasty things. In humans, they cause nausea, seizures, and in some cases, death! Great Hammerheads often have stingray barbs lodged into their faces, so it appears they are unaffected.
FACT #8 Their Range Is Greater Than You Might Think
We tend to think of Hammerheads in the warm waters of South America, Africa, & Asia. But, they inhabit coastal ranges quite far into the northern hemisphere, including around the British Isles.
FACT #9 Bonnetheads Can Reproduce Asexually.
Scientists recently discovered that a female Bonnethead gave birth without mating with a male. The shark in question was in captivity. There were suspicions that the shark had stored male sperm before being captured and then used it later to fertilize her eggs. However, tests proved that the offspring had no paternal DNA. This is the first time that the process called Parthenogenesis has been observed in a large vertebrate.1
FACT #10 Hammerhead Sharks Give Birth To Live Young
A baby hammerhead is called a pup! Females are pregnant for up to 11 months and typically have up to 15 pups, although the Great Hammerhead has over 40 pups. They are, of course, tiny compared to their parents, but they are born completely independent.
FACT #11 Scalloped Hammerhead Sharks Form Schools
Scalloped Hammerheads congregate during the day around seamounts (small peaks in the ocean’s floor). These schools of sharks can contain as many as 500 individuals. It’s unknown why they do this, as Hammerheads are typically solitary hunters, and that’s exactly what they do at nightfall; they disappear off on their own to hunt, returning the next morning to their seamount.
FACT #12 Populations Are Decreasing Significantly
Of the 10 known Hammerheads, 5 are classified as Critically Endangered, 2 are classified as Endangered, and 1 is classified as Vulnerable.2 Sadly, the reason is overfishing. Shark fins are considered a delicacy in Asia. Fishing trawlers harvest hammerheads by cutting off their fins and discarding the rest of the animal.
In Chinese culture, it is believed that shark fins boost sexual potency, increase energy, prevent heart disease, reduce cholesterol, and improve skin. As with many human practices that target animals like this, there is no scientific basis for any of it, and sadly, the continued practice could well lead to the extinction of these wonderful animals.
Fact #13 Hammerhead Sharks can grow quite large
The size of the Hammerheads varies greatly with each species, and scientific data on sizes varies based on different research establishments. But to give an idea of the largest of the Hammerheads, an adult Great Hammerhead can reach a length of up to 3m and live for up to 44 years!
FACT #14 They Aren’t Dangerous To Humans
There have only been 17 recorded Hammerhead attacks on humans since the year 1580, and none of them were fatal. So whilst Hammerheads may look pretty fearsome, they are not particularly a danger to humans. Part of the reason is that most of the hammerhead sharks are too small to cause us any serious damage.3
FACT #15 They Have Small Mouths
When you think of sharks, you might well immediately think of the movie Jaws and a formidable set of sharp teeth. Hammerheads, on the other hand, have quite small mouths compared to many of the other shark species.
Citations
- Queen’s University Belfast. “No Sex Please, We’re Female Sharks.” ScienceDaily. ScienceDaily, 23 May 2007. [Accessed 18/03/2025]. ↩︎
- IUCN Red List Of Threatened Species [Accessed 19/03/2025] ↩︎
- International Shark Attack File [Accessed 19/03/2025] ↩︎
REFERENCES
- Helfman, Gene, and George H. Burgess. Sharks: The Animal Answer Guide, Johns Hopkins University Press, 2014. ProQuest Ebook Central. [Accessed 19/03/2025]
