Which quality is NOT a benefit of a mule over a horse?

Question

Quizplus · Accepted Answer

Mules, being hybrids of donkeys and horses, inherit many beneficial traits such as a hardier digestive system, needing less food, and better endurance in heat. However, their ability to pull larger weight loads is not necessarily superior to that of horses. Horses are often bred for specific tasks including heavy pulling, so this trait can vary widely depending on the breed of horse compared to a mule.

Which Quality Is NOT a Benefit of a Mule Over