  We discuss lattice QCD with one flavor of staggered fermions and show that in
the path integral the baryon contributions can be fully separated from quark
and diquark contributions. The baryonic degrees of freedom are independent of
the gauge field and the corresponding free fermion action describes the baryons
through the joint propagation of three quarks. The non-baryonic dynamics is
described by quark and diquark terms that couple to the gauge field. When
evaluating the quark and diquark contributions in the strong coupling limit the
partition function completely factorizes into baryon bags and a complementary
domain. Baryon bags are regions in space-time where the dynamics is described
by a single free fermion made out of three quarks propagating coherently as a
baryon. Outside the baryon bags the relevant degrees of freedom are monomers
and dimers for quarks and diquarks. The partition sum is a sum over all baryon
bag configurations and for each bag a free fermion determinant appears as a
weight factor.
