Ultimate shoulder rides

What an amazing video !!!
I have never seen this type of chickenfight, I'm not sure I understand all its rules, but I am completely amazed by the show ! I'm not sure what is the most amazing, btw : The sound and fury of the scrum, or the agressivity, <and the balance> of the riders ?? Howevern after viewing the clip a couple of times, I think the most amazing are the "horses" !!! OMG, they carry big, heavy, guys on their shoulders, they keep engaging again and again in that confused scuffle, and while their riders are granted the support of THREE guys who make sure they don't fall,  the horses are alone underneath their massive riders, and the fight lasts for ever ... We see it going for 7.35 minutes, but the riders were already in the saddle before, waiting for some starting signal !!! And at the end of the fight, the victorious riders high-five each other, still riding their exhausted mounts, that no one, btw, even cares to congratulate for their huge efforts!!! It's only when one of those horses collapses that he at last gets some attention from the guys around !!!

Where does this happen ? Is it some kind of national sport ? Could it be allowed at the olympic games ??

Thanks tclaner for this great find !!!