When territory is at stake, whole colonies go to war with one another.

Once a coral senses another is too close, it launches a barrage of stinging cells, and the enemy returns fire.

 

It's a war of numbers, the coral with the greatest firepower will win.

Eventually, the coral on the right forces its opponent to retreat.

 

Yet another small part of the reef has been changed.

Every night this goes on from one end of the Great Barrier Reef to the other.

 

Day and night, the reef is always changing, but that's nothing compared to the impact of the seasons.

In summer, warmer water means more food, making it the best time to bring new life into the world.