The scimitar horned oryx . . . the addax . . . the dama gazelle - three elegant desert antelope that you'd hope to see on a journey through Africa, except that their numbers are dwindling there. Which is why Lara Logan went to Texas -- yes, Texas. There, on large grassland ranches, some exotic species that are endangered in the wild have been brought back in large numbers. But there's a catch: a percentage of the herd is hunted every year by hunters who pay big money for a big catch.