The black rhino is a critically endangered species, according to the World Wildlife Fund, with only about 5,000 remaining worldwide. Poachers kill the animals for their horns, which bring huge amounts of money on the black market, mostly in Asia. As part of an effort to save black rhinos from extinction, conservationists are moving them to safety from areas in Kenya and South Africa where they’re at great risk. One group, called Rhinos Without Borders, is airlifting endangered rhinos to protected areas in Botswana at an estimated cost of $45,000 per animal.