Updated: Oct 5
When many people hear the word 'shark', they think Jaws... they think, big... scary... lots of teeth. Usually they would picture a great white shark (Carcharodon carcharias) or some other stereotypical species. However, there are many, many species of sharks which are nothing like their more famous cousins... Many are much smaller, shaped very differently and have little teeth that really pose no threat to humans. In fact, many are down-right cute! Allow me to introduce you to some of these lesser-known characters and broaden your mind about how a 'shark' really looks...
Most Sharks are Very Small
Whilst there certainly are some spectacular, big sharks, the majority of sharks are actually quite small! Of the 530 plus species of sharks that we know of, 300 of are less than 1 metre in length when fully grown!
For example, there are many different species of catsharks (Family Scyliorhinidae) and bamboo sharks (Family Chiloscyllium), which are small and absolutely adorable! Many also have intricate patterns on their skin, which makes them quite beautiful. You can commonly see sharks like these in aquariums, as they do very well in captivity (Abel & Grubbs, 2020; Ebert et al, 2021).
The smallest shark we know of is the dwarf lantern shark (Etmopterus perryi). These guys are just 20 cm long! But don't get too excited... it is unlikely you will ever see any of these little cuties. They live in very deep oceans, as far down as 400 metres, in the Caribbean!
Some Sharks Do Not Have Sharp Teeth
You hear "shark", you think Jaws, right!? If so, it might surprise you to learn that many sharks do not have sharp teeth! In fact, every single species of shark has completely different dentition (Abel & Grubbs, 2020; Ebert et al, 2021).
Mackerel sharks, like the great white in Jaws, have sharp, serrated teeth, which are perfect for cutting chunks out of their whale and dolphin prey. Similarly, tiger sharks (Galeocerdo cuvier) have serrated teeth that are angled for bite that is strong enough to cut through a turtle's shell (Abel & Grubbs, 2020; Ebert et al, 2021).
Other species, like sandtigers (Carcharius taurus) have very spindley, sharp teeth, perfect for gripping onto their slippery fish prey (Ebert et al, 2021).
However, there are also many sharks with teeth that have evolved for completely different types of prey and therefore, look very different...
For example, horn sharks, like the zebra bullhead shark (Heterodontus zebra), have piercing teeth at the front of their mouth, which they use for grip, but have flattened, crushing teeth at the back (Ebert et al, 2021).
Similarly, houndsharks, like the starry smoothhound (Mustelus asterias) have plate-like, flattened teeth, which are arranged into an interlocking pattern. These teeth are perfect for grinding up the hard parts of their shellfish prey (Abel & Grubbs, 2020; Ebert et al, 2021).
Some Sharks Look More Like Rays
When most people think of sharks, they imagine an animal with a long, slender body, fins at each side, teeth at the front and a strong tail for swimming at the back. However, there are many species of sharks which do not fit this stereotype at all!
For example, angel sharks (Family Squatinidae) have a flattened body, more like their close ray relatives. But don't be fooled, these guys are in fact sharks! They have a powerful tail, like other sharks, which makes them good swimmers, but their flattened body is perfect for the ambush hunting strategy they use to catch their prey. Angel sharks lie on the sandy bottom, perfectly camouflaged, and then spring upon unsuspecting fish that swim by (Abel & Grubbs, 2020; Ebert et al, 2021).
A Few Sharks are Down-Right Bizarre!
But, believe it or not, angel sharks are not even remotely the most bizarre sharks out there! Some sharks have developed truly strange features over their millions of years of evolution...
Take, as an example the sawsharks (Family Pristiophoridae). These sharks are armed with a magnificent "rostrum" or saw, sticking out of the front of their face! The shark uses this saw to dig prey out of sand and slashes it through the water to cut their meal into bite-size pieces (Ebert et al, 2021).
Equally as strange and unrecognisable as a shark are the wobbegongs (Family Orectolobidae). These sharks also look a little like rays, with their flattened body, but they have taken their bottom-dwelling camouflage to the next level - they all have intricately patterned skin to help them blend in perfectly with the background. Some species, like the tasselled wobbegong (Eucrossorhinus dasypogon) have also evolved unusual projections that hang from the front of their face like tassels. These provide the shark incredible camouflage (Abel & Grubbs, 2020; Ebert et al, 2021).
Whilst the large, predatory sharks are magnificent, it is important to remember that there are many, many different species of sharks and they are all very different. They might be less flashy and impressive, but small sharks are also beautiful, and as critical to their respective ecosystems as their bigger cousins. So next time someone tells you sharks are all dangerous and scary, let them know that, in fact, the vast majority of sharks are NOT large, toothy predators!
Abel D & Grubbs D (2020). Shark Biology and Conservation Essentials for Educators, Students, and Enthusiasts. Johns Hopkins University Press.
Ebert DA, Dando M& Fowler S (2021). Sharks of the World: A Complete Guide, Second Edition. Princeton University Press: UK. IBAN: 978-0-691-20599-1.