 Our America editor, Sarah Smith. There are about 15,000 southern white rhinos in the wild in Africa. They're considered to be under threat. But because the rhinos were nearly wiped out, the population is very inbred, making them susceptible to disease and other problems. A team of researchers is now trying to safeguard their future by adding in more genetic diversity, and they're harvesting eggs from southern white rhinos in zoos across Europe to help the rhinos in the wild.