As far as I'm aware the elephants of Mt Elgon in Kenya are the only ones in Africa to venture deep inside caves to get salt. They do it very rarely and there is no predicting when it will happen, so we had to wait for weeks to get this footage. The first time the whole herd entered the cave I was stationed in a hide right at the back of the cave some 150 metres deep. I'll never forget the sounds they made; there were the deepest rumbles that resonated off the cave walls but also terrifying roars that sounded like they should come from something monstrous and unearthly.
It was incredible how they used their trunks like mine sweepers scanning the ground ahead as they walked in the pitch blackness. There was absolutely no light in the cave and we used infra red lights to illuminate for our cameras, which is invisible to the elephants. I couldn't believe the lengths these elephants went to to get at the salt locked up in the cave walls and the idea that generations of elephants could have carved out the depth of cave we see today is an amazing thought.