Sharks have captured our attention for generations. The subject of classic films like Jaws, countless news stories, and plenty of scientific studies, sharks are undoubtedly on our collective radar. After all, Shark Week exists! But what do you really know about sharks? We’ve put together a list of 10 facts about sharks so that you can learn more about these amazing creatures!
#1 Sharks Have Been Around for Much Longer Than You Might Think.
Sharks have been around for a very long time – much longer than you probably think. Based on fossil scales found in the United States and Australia, sharks first appeared in the ocean approximately 455 million years ago. That means sharks existed on Earth before the dinosaurs!
#2 Ancient Sharks Were Huge.
Carcharocles megalodon is the scientific name for an ancient shark that lived approximately 23 to 3.6 million years ago. This massive shark was once the ocean’s most feared predator. As the largest shark to have ever lived, it measured roughly 3 times the length of today’s great white sharks. Its teeth were as large as an adult human’s hand and its powerful bite was capable of tearing chunks of flesh out of the largest whales that lived during that time! Fittingly, the name Carcharocles megalodon means “big-toothed glorious shark.”
#3 There Are Over 500 Species of Shark.
There are more than 500 species of shark living in the ocean today. Sadly, 143 of those are listed as under threat, with some classified as vulnerable and others considered critically endangered. Sharks face threats from many sources, including destructive fishing by humans and the impacts of climate change.
#4 Sharks Don’t Have Bones.
Sharks belong to a group of fish known as elasmobranchs. Instead of a skeleton made of bones, this type of fish has a cartilaginous skeleton – a skeleton made of cartilage. Cartilage is the same stuff that makes up human ears and the tips of our noses. But unlike humans, as they age, sharks deposit calcium salts in their skeletal cartilage to strengthen it. This explains why their jaws are so bone-like and strong.
#5 Sharks Are Apex Predators.
Sharks are apex predators, meaning that they have few natural predators and are therefore at the top of the food chain. This fact has made them the subject of many films and TV shows. However, sharks’ status as apex predators is actually pretty important. Sharks play a significant role in maintaining the health of marine ecosystems; by eating other fish, sharks help keep balance in the food chain and support biodiversity in our oceans.
#6 Sharks Possess a Sixth Sense.
Sharks have a sixth sense of sorts. Ampullae of Lorenzini appear as black spots located near a shark’s eyes, nose, and mouth. These special organs are able to sense the electric fields emitted by other fish in the water. This extra sense helps sharks hone in on their prey during the final phase of attack.
#7 Most Sharks Are Cold-Blooded.
Generally speaking, sharks are cold-blooded. This means that their body temperature matches the water they swim in. However, great white sharks are partially warm-blooded. This allows them to move faster when they are hunting prey.
#8 Sharks Vary Widely in Appearance and Size.
You might be surprised to learn that sharks vary widely in appearance and size. The smallest shark is the dwarf lantern shark, which is about the size of a human hand, and the largest shark is the whale shark, which can measure up to 12 meters long and is about the size of a bus. Goblin sharks can be a bright pink color and blue sharks appear bright blue on the upper part of their bodies. Hammerhead sharks have famously hammer-shaped heads. These are just a few examples of the variety found among sharks.
#9 Shark Skin Has a Texture Similar to Sandpaper.
Shark skin feels similar to sandpaper. Why? Well, shark skin is made up of tiny teeth-like structures called placoid scales, or dermal denticles. These scales point toward a shark’s tail and help reduce friction from the water as a shark swims.
#10 Some Sharks Need to Keep Moving in Order to Breathe – and Some Don’t.
Many species of sharks, including the great white shark, the whale shark, and the mako shark, are obligate ram breathers. This means that they breathe by passing water through their opened mouths and over their gills. They must remain in near-constant motion to avoid asphyxiation. In contrast, some sharks have a spiracle that lets them pull water into their respiratory system without having to move through the water. Bottom-dwelling sharks like angel sharks and nurse sharks use this extra respiratory organ to breathe while they are resting on the seafloor.
Want to learn even more facts about sharks? Watch this captivating video!
Still craving some more science facts? Check out our post about animals!