The tendency for groups of individuals to act together without planned direction
Dogs are born into packs. In the wild, packs are the essential social order. Unlike humans, who use a variety of political processes to determine leadership and rank, dogs sort out their social order by dominance and power. In a wolf pack, there is a Top Dog - a clear leader who is the dominant, Alpha male. He's the Big Dog, with pride of place at the dinner table (well, if wolves had a dinner table!), first in mating, first in decision making for the pack