When you think of a shark, what comes to mind? Maybe you picture a big fin sticking out of the water or a mouth full of sharp teeth. Sharks are some of the most famous animals in the ocean, but do you know what makes a shark a shark?
First of all, all sharks are fish. That might not surprise you since they live and swim in the water. However, sharks are a special kind of fish. One thing that makes them different from other fish, like goldfish, is their skeleton. Our skeletons are made of bone, and so are the skeletons of most kinds of fish. But a shark’s skeleton isn’t made of bone; it’s made of cartilage. You have cartilage in your body too! You can feel it by touching the tip of your nose or wiggling your ear. Cartilage is lighter than bone and bends easily, which helps sharks swim faster and further.
Sharks are also famous for their teeth. Have you ever lost a baby tooth and then had an adult tooth grow in? Sharks lose their teeth all the time throughout their lives and just keep growing new ones. Unlike us, who have one row of teeth, sharks have many rows on the top and bottom. So, when a shark loses a tooth, another one moves up to take its place. Some sharks can lose thousands of teeth during their lives!
If you could touch a shark’s skin, you’d find it feels smooth when you rub your hand in one direction but rough like sandpaper in the other. That’s because a shark’s skin is covered in tiny scales that look a bit like small teeth. These scales help sharks swim quickly and quietly through the water.
There are over 450 types of sharks in the world, which means there are many differences among them. For example, the whale shark is the biggest shark and the largest fish in the world. It can grow as long as a school bus! Despite its size, it eats tiny plants and animals called plankton.
On the other hand, the dwarf lanternshark is so small it could fit in your hand. It lives in the deep ocean where there’s little light, so it has big eyes to see in the dark. It also has special organs that glow, which might help it find food or hide from predators.
Another fascinating shark is the Greenland shark. It spends most of its time in cold water near the sea floor. Scientists have discovered that Greenland sharks can live up to 400 years, making them the longest-living vertebrates we know of!
Scientists are still discovering new kinds of sharks all the time. Who knows what amazing sharks are still out there waiting to be found? If you have a favorite animal or want to learn more about sharks, ask a grown-up to help you explore more. The ocean is full of wonders, and there’s always something new to learn!
Shark Skeleton Experiment: Let’s explore what makes a shark’s skeleton special! Gather some bendy straws and some sticks (like popsicle sticks). The straws represent cartilage, and the sticks represent bones. Try to build a simple fish shape using both materials. Which one is easier to bend and shape? Discuss with a friend or family member why having a skeleton made of cartilage might help sharks swim faster.
Tooth Replacement Game: Create a fun game to understand how sharks replace their teeth. Use a piece of cardboard to draw a shark’s mouth and cut out several rows of teeth. Use removable stickers or small pieces of paper to represent teeth. As you play, pretend some teeth fall out and replace them with new ones. How many teeth can you replace in one minute? Talk about why it’s important for sharks to have so many teeth.
Shark Skin Texture Exploration: Find different materials around your home that feel smooth in one direction and rough in another, like a piece of fabric or a brush. Compare these to the texture of a shark’s skin. How do these textures help sharks swim quietly? Try moving your hand quickly through water with different materials and see how it feels. Discuss how this might help sharks sneak up on their prey.
