Dominance hierarchy can be a form of social stratification. Social stratification is a more general term, one that doesn’t indicate the mechanism.
dominance hierarchy
–noun Animal Behavior.
a system or set of relationships in animal groups that is based on a hierarchical ranking, usually established and maintained by behavior in aggressive encounters: one or a few members hold the highest rank and the others are submissive to those ranking higher and dominant to those ranking lower.
a form of animal social structure in which a linear or nearly linear ranking exists, with each animal dominant over those below it and submissive to those above it in the hierarchy. Dominance hierarchies are best known in social mammals, such as baboons and wolves, and in birds, notably chickens (in which the term peck order or peck right is often applied)
social stratification
noun
the condition of being arranged in social strata or classes within a group