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11 intriguing transparent animals

Transparent sea cucumber

Photo: Larry Madin/Woods Hole Oceanographic Institution

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Transparent sea cucumber

Recently discovered by researchers with the Census of Marine Life, this sea cucumber is so transparent that its digestive tract is on spectacular display.

Found at a depth of 2,750 meters, it is one of many unusual finds discovered by the marine census. When encountered, this cucumber was creeping forward on its many tentacles at about 2 centimeters per minute while sweeping detritus-rich sediment into its mouth.