There was once a wicked tyrant.
One day in the woods he saw a hound chasing a fox. The hound bit the fox, wounding her badly, but she managed to escape.
Then the tyrant heard the hunter shouting as he threw a rock at the dog. "You wretched hound!" The rock broke the dog's leg.
The dog's howl scared the hunter's horse, who bolted and plunged into a ravine, killing them both.
The tyrant was amazed. "I see now: one bad deed leads to another and another."
Thus the tyrant resolved to be a good and just ruler in future.
The Tortoise and the Geese, and Other Fables of Bidpai by Maude Barrows Dutton.
Notes: For another story where a king learns a lesson by observing nature, see the Buddhist Jataka of the monkey and the peas.