The M274 Mule was introduced in 1956 to supplement both the
1⁄4-short-ton (0.23-tonne) trucks ("Jeeps") and 3⁄4-short-ton
(0.68-tonne) trucks (Weapons Carrier Series and M37 series) in airborne
and infantry battalions. The M274 evolved from improvements to a vehicle
designed at the end of World War Two by Willys-Overland as a medical
evacuation litter carrier from areas and terrain that would be a problem
for the standard light vehicle of the period (the Jeep) to access.
Further tests by the US Army at Eglin Field, Florida proved it also
useful as carrier for both supplies and men. In 1948 the US Army
purchased a small number of these test vehicles with the designation the
'Jungle Burden Carrier' for evaluation in jungle warfare and with
airborne forces.