Looking for a way to shark attack your school yard, your neighbor’s garden or your own flower bed? Make these shark fins, place them near amazing shark facts, and you have a funny and educational way to share your passion for sharks! This is also a great way to recycle old cardboard. And the fins look hilarious swimming through a garden. This activity is from The Shark Packet, a curriculum guide designed to accompany the children’s program The Shark Riddle. You may download the whole activity and shark fin templates for free by clicking here. Just look for page 7 in the packet.
Comparing and contrasting characteristics of a group of animals.
Understanding that animals have adaptations to survive in an environment.
Using observations to ask questions and study the world.
Using communication skills to share important information with others.
Pieces of cardboard (used cereal boxes, old packaging boxes, etc.) or posterboard, paintbrush, washable paint (in shark colors like black, brown, gray and blue), scissors or utility knife, pencil, wooden dowels (2 to 4 feet long), duct tape
Background on Dorsal Fins
When people think of sharks, they often imagine a shark’s dorsal fin suddenly slicing through the water, revealing the tip of a powerful predator lurking just below the surface.
In reality, the majority of shark species do not swim with their dorsal fins above the surface. Unlike whales, who must surface to breathe and therefore often end up with their dorsal fins above the water, sharks do not need to surface to breathe. Shark fins do break the surface when they feed on bait that people put in the water. Shark fins also break the surface when sharks enter shallow water, to breed or give birth, such as the lemon shark pupping grounds in the mangrove forests of Florida. But most of the time, as described by the Biology of Sharks and Rays Web site, sharks usually swim far enough below the surface that we don’t see the fins.
When dorsal fins do break the surface, scientists can use the fin shape to identify individual sharks. For great white sharks,
the shape of the dorsal fin is as unique as human fingerprints are for identification. Scientists can see slight differences in the edges of the fins. They use these differences to recognize individual sharks and study the behaviors of different sharks in the water.
Shark fins come in many shapes and sizes. The great hammerhead shark’s fin is taller and pointier than some other species. The great white shark has a “typical” triangular fin shape, one that we have seen many times in movies. The horn shark is a small shark with a spine on its dorsal fins, which helps protect it from predators that try to bite it. Other sharks have shorter and wider dorsal fins. Some fins are basically one color. Some have spots or stripes. The oceanic whitetip shark has a white tip on its dorsal fins. The blacktip reef shark has a black tip on its dorsal fins.
Why do sharks have fins anyway? Sharks are fish, which means they have fins like fish. Dorsal fins are the fins on the back (top) of the fish, used for stabilizing the fish in the water. A dorsal fin is like a keel of a sailboat, which helps it go straight. The dorsal fin works with the pectoral fins, which are like the wings of an airplane, to keep fish from rolling over. Fish also have a tail (or caudal) fin that provides speed and power. The tail fin of the thresher shark is actually used to stun prey.
The main dorsal fin is made mostly of cartilage and dermal collagen fibers, with little muscle tissue. Though it appears rigid, the dorsal fin can bend and warp to help with swimming.
Pre-Activity Discussion Questions
Imagine you are a marine biologist, who is seeing a shark fin for the first time. Make a list of words that come to mind when you think
of shark fins. Fear? Power? And what do shark fins look like? A sailboat’s sail? An airplane’s tail?
Take time to research sharks or watch The Shark Riddle, and make sketches of different kinds of fins. Which fins help keep a fish from rolling over? The dorsal fin and pectoral fins help fish stay upright. Which fins give sharks their power and speed? The tail (or caudal) fin.
Compare the shape of a shark to the shape of an airplane. Compare the shape of a shark to the shape of a sailboat. Why are some
Note: It is better for an adult to cut the shape out of cardboard for safety reasons. Then children can paint and decorate the fins.
1. Choose the shape of a shark’s dorsal fin to use as your guide. You may use the hammerhead or great white fin templates provided in The Shark Packet, which you can trace, or you can use as a guide to draw a bigger version, depending on the size of your cardboard.
2. Draw the shape of the shark’s fin on your cardboard sheet.
3. Using scissors or a utility knife, carefully cut out the shape of the fin.
4. Paint one side of the fin and let the paint dry.
5. After the paint dries, firmly tape a wooden dowel with duct tape to the back side of the fin.
6. Choose an interesting shark fact to feature with your fin. You can make another sign that features this fact, or you may even write the fact on the painted fin. You can find an entire list of amazing shark facts in The Shark Packet, available for download.
7. Choose an interesting place outside and stick the wooden dowel in the dirt, with the fin showing as if it were swimming through some bushes, flowers, etc. If several people make fins, it looks like an entire school of sharks are swimming through someone’s garden! Place your signs with shark facts near the fins, and you’ll have a powerful, attention-getting tool to help people learn about sharks!
Note: Since these are made of cardboard, they can be damaged by water, like rain. If you want to make these fins last longer outside, try re-using and cutting old plastic or foam.