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MEXICO — You've probably heard of a murder of crows, a parade of elephants, a school of fish, a gaggle of geese, a cackle of hyenas, or a parliament of owls. But did you know that a group of rays is called a fever?

Mobula rays live in warm waters around the globe, such as the Sea of Cortez. Divers and snorkelers flock to Baja California Sur to swim with these majestic creatures that have wingspans of up to 17 feet.

This video shows how mesmerizing it is when hundreds of Mobula rays swim together in a fever.

It seems that the rays prefer the fever life, because they usually swarm together like this. One of the only times you'll see them going solo is when they launch from the water for their famous jumps. Mobula rays can leap as high as 6 feet out of the water, which occasionally poses a threat to boats traveling in the area.

Nobody is sure why the rays do their jumps. Some experts say it's to get rid of parasites; others think it's a method of communication. But one of the most popular theories is that they're just showing off in hopes of attracting a mate.