One of the last northern white rhinos left on earth died Monday at the Dvur Králové Zoo in the Czech Republic. Nabiré, a 31-year-old female, suffered complications from a ruptured uterine cyst, according to a statement from the zoo.
Nabiré’s death means that only four northern white rhinos remain alive, down from the 2,000 that roamed central Africa in 1960, National Geographic reports. Poaching, driven by demand for their horns, and habitat loss were the two main causes of the decline. The remaining rhinos are all in captivity. One of them is a male, but at 42 years old, he is past his breeding age.
Right after Nabiré died, scientists removed her healthy left ovary and took it to a lab in Italy for research and reproductive work. The zoo officials hope to preserve her eggs for in vitro fertilization. “It is our moral obligation to try to save them,” Premysl Rabas, director of the Dvur Králové Zoo, said in the statement. “We are the only ones, perhaps with the San Diego Zoo, who have enough collected biological material to do so. We are aware that the chances are slim, but the hopes are still alive.”