POWELL, Ohio -- An Ohio zoo says an African black rhinoceros has died after being treated for an often fatal disease that's commonly found in the species.The Columbus Zoo and Aquarium says the 18-year-old rhino was named Kijito and died early Wednesday after a two-day illness. It says the rhino had repeatedly suffered bouts of a condition known as black rhino syndrome but its cause of death is being investigated.The zoo says there were about 65,000 black rhinos in Africa four decades ago but the population declined sharply to around 2,300 in the wild by the 1990s. It says conservation and anti-poaching efforts have helped increase the population to about 4,200 black rhinos today. The rhinos are called black but actually have a grayish-brown color.
