Today’s Wonder of the Day was inspired by Josh. Josh Wonders, “Why do fish make fish tornadoes?” Thanks for WONDERing with us, Josh!

Have you ever seen a tornado? Tornadoes strike fear into the hearts of even the bravest souls. Made of violent, swirling winds, they destroy buildings and injure people. Only the most daring storm chasers want to get close to a tornado.

But what if you came across a tornado underwater? It might be made of swirling fish instead of strong winds! Does it sound like we’re making this up? Think again! That sight would be what some scientists call a fish “tornado”!

Photographer and marine scientist Octavio Aburto caught a fish tornado on camera at Cabo Pulmo National Park. There, Aburto studies the behavior of several types of jackfish.

During his studies, Aburto witnessed the unique courtship behavior of the bigeye trevally. He saw that large groups of the fish swim quickly together and around one another at high speeds. This creates a moving, swirling column of fish that can only be described as a fish tornado. These events can include thousands of fish!

Aburto witnessed these fish tornadoes on many occasions. However, it was nearly three years before he could to capture one on camera. His photographs and videos have become sensations on the Internet.

Marine biologists who have seen the photographs and videos point out that such behavior is common. It doesn’t always rise to the level of a fish tornado, however. What Aburto captured is special.

If you know much about fish, you probably know that they commonly swim in groups. Upon seeing a group of fish swimming together, many children will immediately exclaim, “A school of fish!”

School is actually a technical term with a particular meaning when it comes to a group of fish. Any group of fish congregating together is called a shoal. For a shoal to be considered a school, it must meet certain criteria. A group of fish is only a school if all the fish are swimming together at the same speed, in the same direction, and turning at the same time.

Why do fish tend to hang out in groups? There are several reasons, but they all boil down to the fact there’s safety — and success — in numbers.

Fish in groups find food easier. Swimming in groups also helps fish find potential mates. If danger approaches, it’s much safer to be part of a large group of fish than to be on your own. And who knows? It may just be more fun for fish to hang out with friends. Don’t you think it would be fun to swim as part of a fish tornado? We do!

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Be sure to tune in tomorrow for a Wonder of the Day that looks like it’s going to be spectacular!