Today, i'm feeling kinda BLUE

Whale Shark

Photograph by Brian Skerry

The sweeping color of sea and sky, blue is a common thread in nature, seen in the cerulean of a whale shark (pictured here), the indigo of a stormy night, and the cobalt of a peacock's feathers. Over the centuries, the hue has come to represent calm, cold, mysticism, and sadness.

Barracuda School

Photograph by Tim Laman

A thick, swirling school of blackfin barracuda plies the blue waters off Sipadan Island, Malaysia. The fish are formidable predators, but they sometimes gather in groups for protection against sharks higher up on the food chain.

Iceberg Penguins

Photograph by Ralph Lee Hopkins

A group of chinstrap penguins lines the edge of an iceberg adrift in Antarctic waters. Chinstraps are among the most abundant penguins, and some colonies live on floating icebergs.

Polar Bear in Svalbard

Photograph by Ralph Lee Hopkins

A polar bear leaps off of sea ice near Devon Island in the Canadian Arctic. Strong swimmers, polar bears have slightly webbed paws to aid in paddling.

Blue-Footed Booby

Photograph by Tim Laman

These distinctive webbed feet belong to a blue-footed booby of the Galápagos Islands. The bluer, the better: Courting males show off with a high-stepping strut—and those with brighter feet are more attractive to potential mates.

Frosted Ferns

Photograph by Annie Griffiths Belt

Frost covers the brilliant blue leaves of lush ferns in New Zealand's Fiordland National Park. The park is an isolated wilderness that's home to more than 700 plants found nowhere else in the world.

photo courtesy of national geographic