Why do some animals have brightly coloured skin?

Brightly coloured skin in animals can serve various purposes, including attracting mates, deterring predators, or warning other animals about toxicity. For example, frogs, like the poison dart frog, use bright colours to signal that they are toxic and should not be eaten. Some birds and reptiles have vibrant colours to attract mates, demonstrating their health and genetic fitness. In other cases, colourful skin provides camouflage or plays a role in temperature regulation.