Northern white rhinoceros
Several species of rhinoceros are critically endangered, but none is on its last legs like the northern white. These magnificent beasts once roamed vast territories in sub-Saharan Africa, but their numbers have rapidly declined over the last century, mostly due to poaching.
Their population in the wild was reduced from 500 in the 1970s down to just four in recent years. Unfortunately, not even these last four could find protection; they have vanished and it is now believed that poachers got to them as well.
This means that the only northern white rhinos still alive are the seven held in captivity. Two of them live at the San Diego Zoo's Safari Park, one resides at the Dvůr Králové Zoo in the Czech Republic, and four are part of a captive breeding program at the Ol Pejeta Conservancy in Kenya, in a last-ditch effort to revive the species.