The immortal jellyfish (Turritopsis dohrnii) can revert to its juvenile form after reaching maturity.

Some dolphins sleep with one half of their brain at a time.

Fact #564 · Ocean

Penguins use their flippers to propel themselves underwater.

Fact #1238 · Ocean

A humpback whale’s song can last for hours.

Fact #549 · Ocean

Some marine animals use bioluminescence to produce light.

Fact #208 · Ocean

Deep-sea creatures often have bioluminescent organs for communication.

Fact #884 · Ocean

The sailfish is among the fastest fish in the ocean.

Fact #397 · Ocean

Dolphins give each other names — they use unique whistle signatures to identify individuals.

Fact #3518 · Ocean

Prehistoric coral reefs were similar to modern reefs.

Fact #707 · Ocean