BigDog

BigDog is a quadrupedal robot created in 2005 by Boston Dynamics, in conjunction with Foster-Miller, the Jet Propulsion Laboratory, and the Harvard University Concord Field Station. BigDog project was funded by the DARPA in the hopes that it will be able to serve as a robotic pack mule to accompany soldiers in terrain too rough for vehicles. Instead of wheels, BigDog uses four legs for movement, allowing it to move across surfaces that would defeat wheels. BigDog is called the world’s most ambitious legged robot". It has been designed to carry 340 pounds (150 kg) alongside a soldier at 4 miles per hour (6.4 km/h), traversing rough terrain at inclines up to 35 degrees. (Source: Thomson Reuters)

LittleDog
LittleDog is a small quadruped robot developed for DARPA by Boston Dynamics for research purpose.