How are mules produced, and why are they useful as farm work animals?

A mule is a hybrid animal produced by crossing a male ass (jackass) with a female horse (mare). These animals are typically sterile.21

Mules are highly valued in livestock farming and industry for several reasons:

• Hardiness: They possess a remarkable ability to withstand severe stress, including extreme heat, irregular feeding, and harsh working conditions that might overwhelm other draft animals.21
• Physical Capability: Mules are surer-footed than horses, making them ideal for navigating precarious or difficult terrain.1
• Intelligence and Temperament: They are considered more intelligent than horses and are known for their self-preservation instincts; unlike horses, they generally refuse to overeat or thrash when trapped in cramped quarters.1
• Versatility: Historically, they were bred for specific roles ranging from heavy draft work and farm labor to mining and pack transport.1

Because of these traits, they remain essential beasts of burden in many parts of the world today.21