Staff Sergeant Reckless, a decorated war horse who held official rank in the United States military, was a racehorse mare of Mongolian breeding. She was purchased in October 1952 for $250 from a Korean stableboy at the Seoul racetrack who needed money to buy an artificial leg for his sister. Reckless was bought by members of the United States Marine Corps and trained to be a pack horse for the Recoilless Rifle Platoon, Anti-Tank Company, 5th Marine Regiment, 1st Marine Division.

The four-legged equine braved minefields and hailing shrapnel to deliver ammunition to her division on the frontlines. In one day alone, performing fifty-one trips up and down treacherous terrain and rescuing wounded comrades-in-arms, Reckless demonstrated her devotion to the Marines who had become her herd.

When not on the front lines, Reckless packed other items for the platoon, and was particularly useful for stringing telephone wire. Carrying reels of wire on her pack that were played out as she walked, she could string as much wire as twelve men on foot. She became the first horse in the Marine Corps known to have participated in an amphibious landing, planning to participate in amphibious landings hundreds of miles south of Inchon.

Reckless was awarded two Purple Hearts for her valor and was officially promoted to staff sergeant twice, a distinction never bestowed upon an animal before or since. She also received a Navy Unit Commendation and a Marine Corps Good Conduct Medal.

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