Orangutans are sexually dimorphic.
Head and body length is about 1.5 meters and the arms have a spread of about 2.2 meters. They have a thin, shaggy coat that is reddish brown in color. Males have large cheek pads, which are made up of deposits of subcutaneous fat bound by connective tissue. These cheek pads continue growing for much of an adult male's life. Orangs have a high, sloping forehead and a bulging snout.