Staff Sergeant Reckless (c. 1948 – May 13, 1968), a decorated war horse who held official rank in the United States military, was a mare of Mongolian horse breeding. Out of a race horse dam, 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. She quickly became part of the unit and was allowed to roam freely through camp, entering the Marines’ tents, where she would sleep on cold nights, and was known for her willingness to eat nearly anything, including scrambled eggs, beer, Coca-Cola and, once, about $30 worth of poker chips.

She served in numerous combat actions during the Korean War, carrying supplies and ammunition, and was also used to evacuate wounded. Learning each supply route after only a couple of trips, she often traveled to deliver supplies to the troops on her own, without benefit of a handler. The highlight of her nine-month military career came in late March 1953 during the Battle for Outpost Vegas when, in a single day, she made 51 solo trips to resupply multiple front line units. She was wounded in combat twice, given the battlefield rank of corporal in 1953, and then a battlefield promotion to sergeant in 1954, several months after the war ended. She also became the first horse in the Marine Corps known to have participated in an amphibious landing, and following the war was awarded two Purple Hearts, a Marine Corps Good Conduct Medal, was included in her unit’s Presidential Unit Citations from two countries, as well as other military honors.

Her wartime service record was featured in The Saturday Evening Post, and LIFE magazine recognized her as one of America’s 100 all-time heroes. She was retired and brought to the United States after the war, where she made appearances on television and participated in the United States Marine Corps birthday ball. She was officially promoted to staff sergeant in 1959 by the Commandant of the Marine Corps. She gave birth to four foals in America and died in May 1968. A plaque and photo were dedicated in her honor at the Marine Corps Base Camp Pendleton stables and a statue of her was dedicated on July 26, 2013 at the National Museum of the Marine Corps in Quantico, Virginia. On May 12, 2018, a bronze statue of Sergeant Reckless was placed and dedicated in the Kentucky Horse Park, Lexington Kentucky.

While the original source of the Devil Dog nickname is up for debate, most know the story from what the Germans called Marines in World War I, Teufel Hunden translated to Devil Dogs, used to describe the fierce fighting style of the Marines at Belleau Wood.

It is a fact that the moniker became widespread in its use and a source of pride beginning in 1918. Recruiting posters featuring an English Bulldog wearing a US helmet chasing a Dachshund with a spiked German helmet appeared during that year proclaiming the “Devil Dog Recruiting Station.”

And it’s all thanks to one Marine: Sgt. Maj. Jiggs, the Corps’ first mascot.

On Oct. 14, 1922, during a formal ceremony, Butler signed the enlistment papers for Jiggs. The contract length: life. (In case you ever thought the fine print on your contract was rough.) Like all Marines, Jiggs had duties — sit, stay, lie down — and the ability to pick up rank, which he did at a cyclic rate. By 1924, the enterprising bulldog had rocketed up the ladder from private to sergeant major.

Unfortunately, due to the short lifespan of English bulldogs, Jiggs passed away on Jan. 9, 1927, and was buried with full military honors in a satin-lined casket at Quantico. But Jiggs’ legacy endured, with the breed becoming the official mascot of the Corps. Before Jiggs passed away, the mantle of Marine Corps mascot passed to Jiggs II.

The first of the Army’s canine members were trained for sentry duty. This was deemed the most pressing need since German and Japanese submarine activity off both coasts raised concerns about the potential landing of saboteurs who might be able to gain access to military facilities and important war industries. In response to this threat, dogs were trained to alert their handlers to any strangers in their vicinity, and on command, to attack those intruders. One of the most vital missions performed by these early sentry dogs was the patrol of America’s coastlines. For this task, the QMC-trained dogs were assigned to Coast Guard handlers who used the dogs’ keen senses to patrol the beaches and other areas along the coast. Within a year, more than 1,800 dog teams patrolled the coastlines. By the end of the war, the QMC would assign 3,174 dogs to the Coast Guard.

Following the war, many dogs were returned to owners or given to their wartime handlers. This involved retraining so the dogs would be able to function safely in a peacetime civilian setting. Due to their classification as government property, any unclaimed dogs had to be sold as surplus, with the new owner footing the bill to return the shipping crate and food bowl to the Army. Still, this program allowed some civilians to purchase a well-trained and physically fit animal for a bargain price.