Could please tell me the significance of the skull that appears at the base of some religious statues?
I am not sure which statues you refer to, but I recall having seen something like what you describe. The human skull in religious iconography is nothing more than a stark reminder of our mortality, and as no one knows when he will die, it is necessary that we are always prepared and use the means to remain in the state of grace.
Rev. Francis J. Hoffman, JCD (Fr. Rocky) is Executive Director of Relevant Radio. Ordained as a priest for Opus Dei in 1992 by Blessed John Paul II, he holds a doctorate in Canon Law from the Pontifical University of the Holy Cross, an MBA from the University of Notre Dame, and a BA in History from Northwestern University. His Question and Answer column appears in several Catholic newspapers and magazines across the country.