The Gama Goat was a six-wheel drive semi-amphibious off-road vehicle originally developed for use by the US military in the Vietnam War. The Goat uses an articulated chassis, so that from distance it appears to be a four-wheel drive vehicle pulling a two-wheel trailer, but it is a single six-wheel vehicle with a four-wheel steering arrangement with the front and rear wheels turning in opposite directions. It was famous for its ability to travel over exceptionally rough and muddy terrain. The vehicle's nickname came from two sources: "Gama" from the name of the inventor of its powered articulated joint, Roger Gamaunt, and "Goat" for its mountain goat-like off-road ability. Its military designation was M561, 6×6 tactical 1¼-ton truck. There was also an ambulance version known as the M792. The vehicle was replaced by a variety of Commercial Utility Cargo Vehicles (CUCV) and Humvees (HMMWV) History The concept for the vehicle came when the French Army reported that the United States Army trucks provided to them were woefully inadequate for the terrain in Vietnam. In 1959, ARPA (now known as DARPA) funded a research project called Project "Agile" to develop a new tactical truck for the Southeast Asia theatre, as well as other projects of interest to the then-looming Vietnam War. Of 50 companies solicited for XM561 proposals, six entered the competition, including Clark, General Motors and LeTourneau Technologies, but on 15 March 1963, the research & development contract was awarded to Chance Vought division of LTV Aerospace, Dallas, Texas, best known for their combat aircraft (though, actually the company did have some experience in designing ground vehicles, particularly, a predecessor of Gama Goat, but they didn't have the truck assembly lines and production experience comparable to those of the mentioned car manufacturers). The principal competitor to the Goat was a tracked XM571 Articulated Utility Carrier developed by Canadair Ltd. of Montreal (yet another aerospace company,) which eventually lost the contest. The research and development contract for the Goat was completed by LTV at cost of about $8.7 million, over three times more expensive than when it had been awarded. The vehicle weighed almost three times as much as originally requested by the military and specified by the operational requirements (). Field testing had not been completed before the mass production order had been issued. During the field tests, it had not been able to go without a breakdown. Final construction