Some deep sea fish have bioluminescent lures — the angler fish's 'fishing rod' glows to attract prey.

Some whales communicate across vast distances underwater.

Certain fish can produce their own light through bioluminescence.

Exploration of the deep sea has revealed that bioluminescence is far more common than previously thought — it may be the dominant form of communication in the ocean's depths.

The deep ocean is the largest habitat on Earth.

Some fish can breathe air in certain conditions.

Trilobites lived in ancient oceans long before dinosaurs.

Many deep-sea fish have transparent or nearly invisible bodies.

Lake Malawi contains more species of fish than any other lake in the world.