But even among the Marines, there are still the few, the proud, the saddle-bound. The Mounted Color Guard, a small cadre operating out of Marine Corps Logistics Base Barstow in California's Mojave Desert, is the service's last remaining true cavalry unit. And it's celebrating 50 years of service in 2017.

What does Calvary do in the Marines?

The Mounted Color Guard participates in parades, ceremonies, and rodeos across the country. But given its size — just nine riders, or “stablemen” — the unit is often spread thin, traveling from coast to coast by truck and trailer.

Do Marines use horses?

The U.S. Marine Corps and special forces

Following the use by special forces soldiers of horses during the invasion of Afghanistan in 2001, the U.S. has shown interest in expanding its mounted training.