In the dark depths of the ocean, many living organisms possess the remarkable ability to emit light – a phenomenon known as bioluminescence, helping deep-sea animals hunt, attract mates, communicate, deter predators, or, conversely, camouflage themselves against the faint downwelling light from above.

Animal colouration also changes dramatically with depth. In the ocean’s twilight zone, red, orange, and dark-coloured organisms are common. Because red wavelengths are rapidly absorbed by water and fail to penetrate into the deep, a red body appears completely dark or virtually black down here. This camouflage enables animals to hide from predators and stalk their prey completely undetected.