Here's why:
* Appearance: Spirit's appearance aligns with the typical Mustang physique: a strong, sturdy build, a short, sturdy neck, and a long, flowing mane and tail.
* Wildness: The film focuses on Spirit's wild nature and his resistance to being tamed, a characteristic deeply associated with Mustangs.
* Setting: The film takes place in the American West, where Mustangs are native and known for their free-spirited nature.
While the breed is never explicitly stated, the filmmakers likely chose a Mustang-like appearance to reinforce Spirit's connection to the wild, untamed landscape of the Cimarron.