Abraham & The Habiru / Apiru
(Tacoma, wa. 98466)
I have always thought that the tribal structure of that area, at that time, was indicative of a colony, rather then a long time settled Place. If Sumer was abandoned because of a disease the survivors would seek shelter wherever possible. If they were city dwellers they would try and enter into a city or seek permission to establish a colony.
If they were an established caravan they would have the diverse people to be secure in starting at least a camp that could have swelled by arriving survivors getting the tribal groups assembled again.
Since Abram was from Sumer and had cavalry at his command has always made me think that the Habiru and the Apiru were the same and recognized by Egypt as an Entity. Probably as the United States treated the Plains Tribes during the 1870s.
Then I think after semi-assimilation into the Pharaohs of Egypt they became the Hebrews, which is English on how the interpretation of the sounds are.