Q: there is a tribe in somalia called the yibbir that are descended from the hebrews. My grandfather was dfrom that clan, does that make me jewish? umm, the yibbir clan does have practicing jews in it, my grandfather's father was a jew. I mean jewish by blood, I'm not jewish in religon.
A: The only way one can be formally considered Jewish, regardless of actual beliefs and practices, is to be the child of a Jewish mother or to formally convert to Judaism. This is true in the Orthodox tradition even in the case that the father is Jewish and the mother is not (non-Orthodoxy does not necessarily say this). In another sense, you might possibly identify yourself as ethnically or culturally Jewish. In this case, you would not actively practice Judaism, but you would identify with other Jews on a cultural level. Neither of these cases seem to apply to you, so you would really not generally be considered Jewish. On the other hand, the Reform movements would consider a child of a Jewish father to be Jewish. In a purely ethnic sense, you have already explained yourself that you have hebrew ancestry, so it would be reasonable for you to identify as Jewish, and in reality, being Jewish is often more of a self-identifying ethnicity than a true test of ancestry.