Botswana began removing the horns from its rhinos and moving them away from the iconic Okavango Delta as an unprecedented poaching crisis threatens their survival in the country. The government said that at least 56 of the animals had been killed by poachers in the past two years, marking the worst onslaught since Botswana’s black rhino population was wiped out in 1992 and the number of white rhinos dropped to just 27.