Suri lip plates

Who are these women? We have all seen these images, Suri women wearing lip plates. But who are they really and how did this practice become a part of their tradition?I love the way they start to question this form of body modification. Why are they doing this and where did it start? This is not to say that there is a right or a wrong answer, but looking at something which many (and now even some of them) perceive to be so strange, is what I find questions my own perception of such tribes.