Here's why:
* Howrse focuses on creating your own unique horse: Howrse's breeding system is designed for you to create your own unique horses with various appearances and skills. You can choose from different base horse breeds and then combine them through breeding to create your own unique line.
* No specific breed options for wild horses: Howrse doesn't have specific breed options for wild horses like Mustangs.
Here's what you CAN do on Howrse:
* Choose a base breed that resembles a Mustang: While you can't breed a specific "Mustang," you can pick a base breed with characteristics similar to a Mustang, like the American Quarter Horse or the Appaloosa, and then breed it with other horses to create your own unique horse that has some Mustang traits.
* Focus on the "Wild" coat type: You can choose the "Wild" coat type for your horses, which will give them a more wild-looking appearance.
* Create a unique "Mustang" line: By consistently breeding horses with desired traits, you can create your own unique line of horses that have a similar look and feel to a Mustang.
Remember, the beauty of Howrse is in the creativity and freedom to design your own unique horses. While you can't breed a specific "Mustang," you can create a horse that reflects the spirit and style of a Mustang through careful breeding and selecting desired traits.