Marius Els was mauled to death by his 'pet' hippo, who he was filmed riding earlier this year [Photo: Barcroft Media via Getty Images]

A man has been mauled to death by his pet hippo - who he previously described as "like a son to me". Farmer Marius Els was found dead in a river after being repeatedly bitten by the huge animal, who weighs more than a ton.

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Mr Els, from the Free State province in South Africa, had adopted the hippo, named Humphrey, and footage of him riding him went viral earlier this year. He died on Sunday after being mauled and dragged into the Vaal River close to his home by the six-year-old animal.

 Mr Els has previously said Humphrey is 'like a son to me' [Photo: Barcroft Media via Getty Images]

Mr Els, 40, previously said that Humphrey responded to his calls and would enjoy playing with him. "It's a little bit dangerous, but I trust him with my heart that he will not harm anybody. I can swim with him. I go in the water. He allows me to get on his back, and I ride him like a horse. He swims with me."

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The farmer then added: "He's like a son to me. There's a relationship between me and Humphrey and that's what some people don't understand. They think you can only have a relationship with dogs, cats and domestic animals. But I have a relationship with the most dangerous animal in Africa."

  The man had been bitten several times [Photo: Courtesy]

Ambulance service spokesman Jeffrey Wicks said: "Paramedics responded to the scene to find that the man had been bitten several times by the animal. It had also been immersed in the river for an unknown period." Humphrey, who is six, was found as a calf and had been raised as a pet in Free State.

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Mr Els, a former army major, would even brush the hippo's teeth, saying he had built a bond with him.