The word "auction" usually makes us think of art or wine. We rarely think of threatened species. However, rich people with at least $10 million can bid for 1,993 rhinos on International Save the Rhino Day. A South African multi-millionaire conservationist, John Hume, is selling his rhinos. He started a breeding project 30 years ago with 200 animals. He increased his stock by ten-fold. He is also selling his 8,500-hectare ranch.

Mr Hume owns over 10 per cent of the world's rhinos. He spent $150 million on his project, but can no longer afford it. He has to pay vets' bills, security guards and helicopter patrols. He said he used all his life savings and has run out of money. He hopes a billionaire will "save the population of rhinos from extinction rather than own a super-yacht". He said: "Rhinos are underdogs. They stand the least chance of surviving poaching."