Zebra finches (Taeniopygia guttata) are dimorphic. That is to say that the males and females have different coloration. Males have a number of distinguishing features including: orange cheek patches, stripes on the throat, black bar on the breast and a chestnut colored flank with white spots. Females lack these features and are gray in those areas mentioned. Beak color is generally a brighter red in males and a orange color in females. This is variable based on the breeding condition of the birds. Juveniles fledge looking like females, but with a black beak. The beak and adult colors are usually complete by the time the young are 90 days old.