Final answer:
Tribal societies joined together for protection, resource management, and united actions.
Step-by-step explanation:
Tribal societies generally consisted of autonomous bands capable of independently sustaining themselves. These bands joined together for the purpose of protection, resource management, migration, and engaging in united actions like raids on other clans.
For example, Eurasian tribes were loosely organized and open to anyone who was willing to obey the leader. Clans would drift in and out of tribes based on their needs and wishes. Sometimes multiple tribes would unite under a skillful or charismatic leader, creating a larger confederation for a short-lived period.
Therefore, tribal societies joined together to better protect their herds and households, cooperate on resource management and migration, and engage in united actions with other clans.