If you think about it, Voli's people, The Ursine, has a relation to Vastaya

As you can see, they worship/their god is volibear, which is a demi-god. And all of those people who became an ursine strangely become bear people. So in my imagination it has something to do with giving off vastayan blood by the elder or something of the tribe or they just want to become like volibear. Another theory of mine is that udyr will be retcon as an ursine member because, bear clothes,vastayan blood and a wild culture. Another theory is that maybe the god sejuani's tribe worship is volibear.

BTW, I love Ornn because he particularly retcon some lost champs like anivia and voli