Footage shows the good-natured rhino relaxing with its hind legs in the water as the hippo positions itself in front of the horned creature.
The large mammal grunts several times before opening its mouth and letting out a huge roar.
But the relaxing rhino is unphased by the hippo’s aggressive behaviour and continues to enjoy its spot in the water.
Angered by its newfound enemy’s cool exterior, the hippo lunges forward and uses its jaws to power the rhino under the water.
“Hippos become extremely aggressive in drought”
Stanley Robertson, game ranger
Caught off-guard, the rhinoceros attempts to pick itself up but fails miserably under the pressure of its attacker and can be seen flailing in the waterhole before the clip ends.
The video was filmed in the Klein Karoo region in the Western Province of South Africa.
The rhino would normally have used its trusty horn to counter the attack but it was removed to protect it from poachers.
“We arrived at a dam to find a rhino on its way to get a drink. It seemed to be pretty dry, and this could have been the major cause for the hippos being over protective of the waterhole,” game ranger Stanley Robertson told African wildlife website LatestSighting.com.
“Hippos become extremely aggressive in drought. As the hippo pushed the rhino into the water, a feeling of adrenaline took over, next was complete and utter shock mixed with disbelief.
“Never in a million years did I expect to see anything like this in my life.
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“The hippo was protecting his waterhole and pulled out one massive attack on the baffled rhino. The rhino didn’t stand a chance under the hippo’s sheer force.
“It was hard to watch and not intervene, but that is nature. This is a very rare, rare sighting indeed.”
The nature reserve wishes to remain anonymous to protect rhinos breeding there.
Hippos are one of the most dangerous animals in Africa, killing 500 people a year and easily able to outrun humans.
Adult rhinos are not preyed upon by any other species than humans.
In 2015, over 1,338 were killed in South Africa – a 300% increase on 2010’s statistics.