How and why?

How, very slowly over many years. Why, same reason why some people choose to let a book or person behind a podium dictate how they live their lives.

If I remember correctly from my internet travels, a ring is added every year. Over time, this happens.

If they remove the rings, their necks won't support their head...

The real question here is why.....?

Must have one hell of a sex life

This was the inspiration for ABBA's monster hit "Ring Ring".

Darwin would be shoked to see it.

This is an age old tradition, going on even during Darwin's time. He was probably aware of it, but didn't care. Darwin was a Naturalist focused more on animals then comparative anthropology or sociology. Given what I learned about this tradition the first time I discovered it from Natural Geographic Magazine, that guy is not just an elder in the tribe and therefore important, but he's a stud too. Those rings are worn around the neck by both men and women of the tribe and they are symbols of their sexual abilities, real or otherwise. And now that I have shown my age and nerdiness I'm going to go back over here and hide.

If They Commit adultery they remove the rings and the neck collapses.

nope.avi