Long-tailed macaques in Lopburi, Thailand, use human hair as if it were dental floss. This eccentric behavior is seen mainly in a large group of macaques that live at the old Buddhist shrine of Prang Sam Yot. Many monkeys of this group take hair and sort a few pieces to make a string and then brush their teeth by pulling it tightly with right and left hands alternatively between their teeth. This habit is not seen in the other localities near Lopburi and is rare even in the surrounding groups. Monkeys in the Prang Sam Yot shrine are worshipped as servants of God and people respect them, even when they ride on their heads. This behavior could be considered a newly occurring cultural behavior, which has become established under very specialized circumstances.