And then there were 4, rare rhino dies at Czech zoo

Only four northern white rhinos remain on earth after a 31-year-old female named Nabire died in the Czech Republic late on Monday, zookeepers said.

The animal born at Dvur Kralove zoo in the country's north died from complications of a ruptured cyst, the zoo said in a statement on Tuesday.

"Her death is a symbol of the catastrophic decline of rhinos due to a senseless human greed. Her species is on the very brink of extinction," said zoo director Premysl Rabas.  

The northern white rhinoceros has been nearly wiped out by hunting and poaching for their horns, and by wars in Africa, according to the World Wildlife Foundation.

The four remaining rhinos include Nola, an elderly female living at a zoo in San Diego, and Sudan, an elderly male living with two females -- Najin and her daughter Fatu -- on the Ol Pejeta reserve in Kenya.   

The Ol Pejeta rhinos were shipped from the Czech zoo in 2009 in the hope that the natural environment would encourage breeding. That hope has faded.

Dvur Kralove is the world's only zoo to have succeeded at the captive breeding of the rare rhino.