American Mammoth Jackstock

The American Mammoth Jackstock is the largest breed of donkey in North America, originally developed in the United States from imported European breeds. It was bred primarily to produce strong work mules, with early breeding efforts led by George Washington and other agricultural pioneers.

Physical Characteristics

• Size: Jacks (males) must stand at least 14 hands (56 inches, 142 cm), while jennets (females) must be at least 13.2 hands (54 inches, 137 cm).
• Weight: They are large and muscular, often exceeding 1,000 lbs.
• Color: Typically black, brown, or gray, though some variations exist.
• Distinct Features: They have long ears, a strong build, and a calm temperament.

History & Development

• The breed was developed from Maltese, Baudet du Poitou, Andalusian, Majorcan, and Catalan donkeys.
• The King of Spain gifted George Washington an Andalusian jack in 1785, which helped establish the breed.
• By 1800, large breeds of asses were found in Kentucky, Tennessee, and Missouri, becoming key mule-producing areas.

Behavior & Uses

• Temperament: Mammoth Jackstock donkeys are gentle, intelligent, and hardworking.
• Primary Use: Historically bred for mule production, but now also used for riding, driving, and farm work.
• Conservation Status: The breed’s population declined in the 20th century, but conservation efforts are helping to preserve it.