Customary law in tribal societies refers to the unwritten, traditional rules and norms that govern behavior, maintain social order, and resolve disputes within a community. Unlike formal, codified legal systems of states, customary law is deeply embedded in the social fabric, passed down through generations, and enforced primarily through community consensus, social pressure, and the authority of elders or traditional leaders.

Functioning of Customary Law:

1. Maintaining Social Order: Customary law provides a framework for acceptable behavior, defining rights, duties, and responsibilities for individuals and groups. It regulates aspects like marriage, family relations, property ownership, resource management, and inter-group interactions, thereby preventing chaos and promoting stability.
2. Dispute Resolution: It offers established procedures for resolving conflicts, ranging from minor disagreements to serious offenses like theft or assault. Resolution often focuses on reconciliation, compensation, and restoring harmony within the community rather than punitive punishment.
3. Reinforcing Norms and Values: Customary law embodies the core values, ethics, and moral principles of the society. Its enforcement reinforces these norms, ensuring cultural continuity and collective identity.
4. Social Control: Through mechanisms like public shaming, ostracism, or fines, customary law exerts social control, encouraging conformity and deterring deviant behavior. The fear of community disapproval is often a powerful deterrent.
5. Resource Management: It often dictates how common resources (land, water, forests) are accessed, used, and conserved, ensuring equitable distribution and sustainability within the community.

Sources of Customary Law:

1. Ancestral Traditions and Practices: The most fundamental source is the accumulated wisdom and practices of ancestors. What has 'always been done' or 'how our forefathers did it' forms the bedrock of customary law. These traditions are often recounted through oral histories, myths, and rituals.
2. Elders and Traditional Leaders: Elders, chiefs, headmen, or councils of respected individuals serve as custodians and interpreters of customary law. Their knowledge of precedents, community history, and moral principles makes their pronouncements authoritative. They mediate disputes and apply traditional rules to specific cases.
3. Community Consensus and Public Opinion: The collective agreement and shared understanding of what is right and wrong within the community play a significant role. New customs can emerge and old ones can evolve through general acceptance and practice over time. Public opinion acts as a powerful informal enforcement mechanism.
4. Religious and Spiritual Beliefs: In many tribal societies, customary law is inextricably linked with religious beliefs, spiritual practices, and the will of deities or ancestors. Transgressions against customary law are often seen as offenses against the spiritual realm, carrying supernatural consequences.
5. Case Precedents: While unwritten, past resolutions of disputes and the decisions made by elders or councils in specific cases serve as precedents, guiding future judgments and interpretations of customary law. These are remembered and referred to in subsequent deliberations.

Customary law, therefore, is a dynamic system, constantly interpreted and re-interpreted, yet firmly rooted in the historical and cultural identity of the tribal community it serves.