As others have suggested, looking at where the animal the tribe is said to be protected by, though I often it's like the tribe emulates the behaviour of the animals as a means of staying alive and surviving in the same environment they do.
I wouldn't try to go into too much detail about how the tribes work and function though. Until we know more officially, I think it's better to keep it open to interpretation. There could be tribes of the same letter that are different depending on who's in them or wherabouts they live. That way you don't get the issue of trying to assume or guess too much, or feel conflicted when someone else has wholly different ideas.
I wouldn't try to go into too much detail about how the tribes work and function though. Until we know more officially, I think it's better to keep it open to interpretation. There could be tribes of the same letter that are different depending on who's in them or wherabouts they live. That way you don't get the issue of trying to assume or guess too much, or feel conflicted when someone else has wholly different ideas.