Zebra stripes have a number of functions. Most scientists agree that the function of a zebra's stripes is to ward off biting flies, which can carry deadly diseases. But not all scientists are convinced that zebra stripes serve that purpose. Some believe that the stipes provide camouflage by reducing the zebra's contrast against its surroundings. The stripes may also help zebras blend into their environment by making them appear lighter or darker depending on the light conditions and by creating a pattern that is more difficult to see for big predators, such as tigers or lions. Some scientists believe that stripes are used to communicate between herds. They may also be used as visual aids to identify zebra families.