By Sara Amundson and Kitty Block
Hawaiian spinner dolphins, named for their acrobatic displays like leaping out of the water and spinning in the air, are nocturnal. To make it harder for sharks to detect them, they hunt for food and socialize at night. During the day, they rest in sheltered coves—safe from sharks and other ocean dangers. Because dolphins must be conscious in order to breathe, in these coves they still swim and breathe slowly while doing their version of “napping.”