This is a pygmy seahorse.
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It's one of the smallest species of seahorses in the world, smaller than a paper clip.
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Camouflage is critical to their survival. It's how they hide from predators. The seahorses are too small and too delicate to make it on their own. So unless they find a place that they fit in perfectly, they'll die.
So the pygmy seahorses spend their entire adult lives on a type of coral called a sea fan.
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Orange pygmy seahorses live on orange sea fans.
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Purple seahorses live on purple sea fans.
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But here's the mystery. Do they search for a coral that matches their color, or do they change their color to match the coral?
To explore that question, you have to watch the process unfold, and no one had ever done that until this year. Biologists went to the Philippines and collected a mating pair of orange pygmy seahorses from a sea fan 80 feet below the surface. They rushed them back to the California Academy of Sciences in San Francisco, and there, for the first time in an aquarium, the pygmy seahorses survived. The scientists watched the male and female seahorses performing their daily courtship dance.
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They saw baby seahorses pop out of their father's brood pouch.
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The babies all started out a dull brown color.
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So scientists wanted to know, what would happen if they provided a purple sea fan to the offspring of orange seahorses? And they got their answer. The babies turned purple. They grew calcified bumps called tubercles
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to match the coral's texture. And there, they stayed. We humans tend to think of who we are as mostly fixed. But in the ocean, identity can be a fluid and mysterious thing.
