Why does God call the great empires in Daniel 'beasts'?

Les explains that God chose the word "beast" because all these great empires, from Daniel's point of view, are bestial in their behavior, in their greed, and in the way they treat their subjects. He notes that through human history, unless one lived among the very elite ruling class, life for most people was mere existence under abject poverty, slavery, and oppression. Human rights were not delineated until the Magna Charta came out of England in about the 14th century, and even in Western civilizations there is only a semblance of human rights, not utopia. Daniel sees these empires come out of the mass of humanity, bestial in their makeup, unfolding as Nebuchadnezzar saw them. The first is like a lion—Babylon—instead of the head of gold, and it had eagles' wings.