Complex specialization is the mark of an advanced society. The first form of specialization comes with the advent of the sexes. It developes with the species in which not only does the mother bare children and defends them, but, also, the father provides food.
Complex specialization starts with the developement of tools. Some are better at fabricating the tools, some are better at using them. As tools and trades become more numerous, specialization gets more complex.
The more advanced the society, the more complex the specialization. The harder to understand the society also. It’s what happened with Europeans when they came into contact with the Chinese and the Japanese.
Specialization will apply to more advanced societies then ours, human or otherwise…