At Arlington National Cemetery, six solemn horses help deliver departed service members to their final resting places. These are the caisson horses, who quietly play an important role in the U.S. military by honoring its service members. And when these iconic horses have served their time, they become available for adoption by private owners. But prospective adopters should be prepared to pass strict muster before they can bring one of these retired equine veterans home.

Established in 1784, the 3d U.S. Infantry Regiment (The Old Guard) is the nation’s oldest active infantry regiment and has long been the face of the U.S. Army. Its 1/3 Battalion HHC Caisson Platoon represents all branches of the U.S. military at presidential inaugurations, parades, and other ceremonial events. But the horses of the caisson platoon are most famous for the role they play pulling the caisson carrying fallen veterans’ caskets during funerals at Arlington National Cemetery.

1st Lt. Austin Hatch, public affairs officer for the caisson platoon, said most of the horses that pull the caisson are draft-crosses and Percherons. “But were have some light-breed horses such as Standardbreds, Morgan-crosses, Thoroughbreds, and a mustang,” he added.

Whatever their breed, caisson horses are purchased outright from private individuals or donated by their owners for service in the platoon. Old Guard horses are saddle-trained, but depending on their training level and personality, they could undergo between a few months to a year of rigorous training to prepare them for the work they’ll do as part of the caisson, Hatch said