Many animals are able to navigate using the Sun as a compass. Orientation cues from the position of the Sun in the sky are combined with an indication of time from the animal's internal clock. There is evidence that some animals can navigate using celestial cues, such as the position of the Sun. Since the Sun apparently moves in the sky, navigation by this means also requires an internal clock. Many animals depend on such a clock to maintain their circadian rhythm. Animals that use sun compass orientation are fish, birds, sea turtles, butterflies, bees, sandhoppers, reptiles, and ants.