Cross River gorillas reside in small populations split from other subpopulations of the species. Their immunology centres on the interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes. Species and subspecies which have critically endangered subpopulations (or stocks) are indicated. In mice, monocytes can be divided in two subpopulations. Species and subspecies which have endangered subpopulations (or stocks) are indicated. Species and subspecies which have vulnerable subpopulations (or stocks) are indicated. There are 15 species, nine subspecies, and nine subpopulations of cetartiodactyl assessed as critically endangered. Species and subspecies which have least concern subpopulations (or stocks) are indicated. Species and subspecies which have near threatened subpopulations (or stocks) are indicated. They exist within seven subpopulations which are genetically and geographically isolated. CD106 also exists on the surface of some subpopulations of mesenchymal stem cells(MSC). Strains of "T. rubrum" form two distinct biogeographical subpopulations. It created bear management units based on seven geographically distinct bear subpopulations. Specific Mexican subpopulations are listed as endangered. There have been numerous other subpopulations of memory T cells suggested.