Symbolism, Imagery, Allegory
The play makes many references to animals, from Lear's comparison of Goneril to a "detested kite" (1.4.274)—which is not just a child's toy but also a bird of prey—to Albany's comparison of humanity to sharks (4.2.60-61).
What's the point? It seems that humans are no better than animals, at least in King Lear.