In the history of warfare, the role of horses, mules and other pack animals or cavalry mounts cannot be overestimated.  But with the advent of mechanization in the 20th century they all but disappeared.

A new section has been added to Olive-Drab.com with details on the use of animals in the U.S. military as well as the story of how mechanizaion was introduced.  The modern role of the few remaining animals is also covered, stimulated by the horse soldiers in Afghanistan in 2001 (mounted SOF riding with the Northern Alliance).

The Military Horses and Mules section starts at the linked page.