  We argue that the confined and deconfined phases in gauge theories are
connected by a partially deconfined phase (i.e. SU(M) in SU(N), where M<N, is
deconfined), which can be stable or unstable depending on the details of the
theory. When this phase is unstable, it is the gauge theory counterpart of the
small black hole phase in the dual string theory. Partial deconfinement is
closely related to the Gross-Witten-Wadia transition, and is likely to be
relevant to the QCD phase transition.
  The mechanism of partial deconfinement is related to a generic property of a
class of systems. As an instructive example, we demonstrate the similarity
between the Yang-Mills theory/string theory and a mathematical model of the
collective behavior of ants [Beekman et al., Proceedings of the National
Academy of Sciences, 2001]. By identifying the D-brane, open string and black
hole with the ant, pheromone and ant trail, the dynamics of two systems closely
resemble with each other, and qualitatively the same phase structures are
obtained.
