Sometimes they warn that the animal is poisonous, like the bright red of arrow-poison frogs. Sometimes they match the animal's surroundings to hide it from predators - or from its prey. This is called camouflage. Ground-nesting birds like the nightjar are mottled brown and are hard for hunters to spot among fallen leaves. Tigers are striped like dry grass so their prey cannot see them until too late.
Chameleons can even change their colour to match their backgrounds.
Animal senses Sea creatures rely on smell and taste to tell them of food and danger, detecting tiny particles drifting in the water. Eyesight is less important because water is often cloudy. A sense of balance is important, too, and many creatures have simple balance organs called statocysts. For animals that live on land or in the air, however, sight is usually the most important sense. Hearing and smell are important, too, and bats 'see' with the echo of their high-pitched squeaks.