Why does the dog die in the elegy on the death of a mad dog?

In "On the Death of a Mad Dog," the dog dies as a consequence of its madness, which serves as a metaphor for the destructive nature of irrationality and violence. The dog's rabid behavior ultimately leads to its demise, highlighting themes of loss and the inevitability of death. The poem reflects on the fragility of life and the impact of uncontrollable forces, both in nature and within human society.