Symbolism of pelican appears from the Physiologus
(II century AD), a collection of legends and stories about animals, plants, stones which was written in Greek in Alexandria by an unknown author. Descriptions are followed by the morals related to the Christian religion. It was very popular at that time to look for religious associations and manifestations of divine in nature. Pelican is described as a bird living in Egypt on the banks of the river Nile. He loves his children a lot but when they grow up they start to fight against his parents. They kill their young and morn for three days. Then their mother pecks her side and revives her children with her blood. The moral is that we strike God with our sins but he resurrects us with his own blood. That action was associated with the resurrection of Jesus Christ. Later Physiologus
was translated to Latin and other European languages. During the Middle Ages pelican became a hero of Bestiary
literature as a symbol of self-sacrifice and paternal love. His example was cited by St Augustine, Origen, Thomas Aquinas. As the result the image of pelican was broadly used in Christian churches.
In Bible crocodile is mentioned as one of the monsters of chaos. Because of this fact crocodile was later associated with the Devil in Christian symbolism. His natural enemy hydra kills him from inside like Jesus Christ destroyed Hell after having descended there for three days. Hydra represents Christ and crocodile stands for Hell. The hydra rolls itself into damp mud till its look is indistinguishable, and then makes its way into the mouth of the crocodile, which swallows it unawares, and instantly bursts asunder. During the Middle Ages stuffed crocodiles were chained on the walls of the churches. They represented chained Devil.