Why do monks and nuns have their heads shaven?
In Buddhas time, followers of monastic life already had their heads shaven. The Buddha prescribed their ascetic appearance with simple robes and a shaven head so that they would not become conceited and attach to their appearance and good looks. Shaving the head also signifies renunciation from worldly pleasures. From the traditional Buddhist viewpoint, hair represents impurity. Removing it symbolizes ones dedication to eradicate all defilements.