Seeing in Colour 2021 Nature The natural world is full of colours. For us, they are a source of beauty, but for animals they are a tool for survival. David Attenborough reveals the extraordinary ways in which animals use colour: to win a mate, to fight off rivals and to warn enemies. New camera technologies - some developed especially for this series – also allow us to see colours and patterns usually invisible to human eyes. Ultraviolet cameras reveal bright signals on a butterfly’s wings and facial markings on yellow damselfish that are used as secret communication channels. Some animals can also detect polarized light, and specialist cameras can now show us how fiddler crabs see the world, and how mantis shrimp have strange polarization patterns on their bodies to signal to a mate or rival.