Vernon Jones (1912)
195. THE MULE
One morning a Mule, who had too much to eat and too little to do, began to think himself a very fine fellow indeed, and frisked about saying, "My father was undoubtedly a high-spirited horse and I take after him entirely." But very soon afterwards he was put into the harness and compelled to go a very long way with a heavy load behind him. At the end of the day, exhausted by his unusual exertions, he said dejectedly to himself, "I must have been mistaken about my father; he can only have been an ass after all."
Aesop's Fables: A New Translation by V.S. Vernon Jones with illustrations by Arthur Rackham (1912). This book is available online at Project Gutenberg.