Today’s Wonder of the Day was inspired by sean. sean Wonders, “Is the cookiecutter shark the most dangerous shark although it lives more than 4,00 feet deep in the ocean?” Thanks for WONDERing with us, sean!

Have you ever been to the beach? Many people love going to the beach on vacation. They play volleyball, relax in a beach chair, and swim in ocean waves. The beach is a lot of fun. However, it can also be a dangerous place. Many people stay out of the water for fear of sharks.

Anyone who’s seen Jaws knows how scary shark attacks look. While they aren’t common, shark attacks do happen.  What do you picture when you think of sharks? Many see a stalking predator with large teeth. However, not all sharks are dangerous to people! Have you ever heard of the cookiecutter shark?

Cookiecutter sharks live in the Pacific and Atlantic Oceans. They’re found off the coasts of many islands near the equator. During the day, cookiecutter sharks stay deep below the water’s surface. We’ve found them as far down as 2.3 miles (3.7 kilometers) below the surface! At night, they rise much closer to the surface to find food.

Full grown cookiecutter sharks are 14-22 inches (36-56 centimeters) long. They have several small fins and large, green eyes. The sharks are dark brown on top, but their stomachs glow! Tiny photophores cover their undersides and make a faint green light. From below, creatures looking up at the shark think their stomachs are light from the surface. They see dark patches on the shark’s neck that look like small fish. They swim toward the shark, expecting to find their dinner. Instead, they find the teeth of the cookiecutter shark!

The sharks’ feeding habits got them the name “cookiecutter.” Their mouths are lined with sharp teeth used to fasten onto prey. Once latched on, the sharks turn in a circle. This leaves a perfectly round bite mark. Resembling cookies, these bites appear on dolphins, whales, squids, and many other marine animals. The bites are not deadly, but the unfortunate prey will carry the cookie-shaped mark for a long time.

Are cookiecutter sharks dangerous to humans? Experts say no. Cookiecutter sharks live deep in the ocean, so they rarely come into contact with people. However, a long-distance swimmer reported the first known cookiecutter bite on a human in 2009. The swimmer survived, but it took nine months for his wound to heal.

Humans may be safe, but submarines need to watch out! Cookiecutter sharks have damaged the sonar equipment of many subs, causing oil to leak out and break the equipment. The United States Navy has had to repair multiple subs due to damage from cookiecutter shark bites.

How worried should you be about the cookiecutter shark? Its bites are painful and can cause serious damage, but most people need not worry at all. Cookiecutter sharks won’t ruin your day at the beach! If you plan to swim in the deeper ocean, do so during the day. At that time, the cookiecutter shark is still well below the surface.

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