I have had the good fortune of being able to observe prairie dogs numerous times on family trips to the zoo(s). They (like squirrels) are rather comical to watch. They will run along, and then just flop down to rest. Sometimes laying down on, or even sitting up on another prairie dog.
This scene is most likely a very natural one in the wild. While other members of the family are busy, there are always a few standing guard, watching for danger from predators.