As the 20th century drew to a close the Sumatran rhino captive breeding program, launched in 1984, had yet to produce a single calf.Home to the last two Sumatran rhinos in the United States, the Cincinnati Zoo made several key discoveries about the species’ reproductive behavior, including the fact that females only ovulate when they have contact with males.Andalas, the first Sumatran rhino bred in captivity in more than a century, was born in Cincinnati in 2001. This success, and the subsequent birth of four other calves, has led to a re-evaluation of the program as a whole.Now, attention is turned to breeding centers in the rhinos’ original habitat as the future of captive breeding efforts. This is the third article in our four-part series “The Rhino Debacle.” Read Part One and Part Two. As we walk out into the zoo enclosure, Cossatot comes over to greet me. Cossatot is a capybara, the size of a very big dog; his species is the world’s largest rodent. He quickly determines from smelling my hands that I’ve neglected to bring him a treat. Looking a bit put out, he goes back to lounging in his one-man kingdom. But where Cossatot reigns was once the domain of an even larger, far more endangered animal. Little does Cossatot know, but his kingdom has made history. I’m visiting the old Sumatran rhino enclosures of Cincinnati Zoo with Terri Roth, head of the zoo’s Center for Conservation and Research of Endangered Wildlife (CREW), and Paul Reinhart, leader of the team that cared daily for the rhinos. Terri Roth inside one of the two enclosures at the Cincinnati Zoo that once housed Sumatran rhinos. Today the enclosures house a regal capybara named Cossatot and two emus. Image by Jeremy Hance for Mongabay. Roth jokes that the enclosures have fallen far from their glory days when they housed arguably the rarest large terrestrial mammal on Earth. The two enclosures — one for the male rhino, Ipuh, and the other for the female, Emi, and her calves — are now the domain of Cossatot and a pair of nervous emus. Above them are half-million-dollar metal structures that look like giant rectangular umbrellas, built to shade the rhinos’ eyes from the sun, just as the canopy does in the rainforest, and prevent severe eye damage. “Every day we walk in here and I look at those pictures,” Reinhart says, pointing to photos of all the rhinos — Ipuh and Emi, Andalas and Suci, and, most beloved of all, Harapan — that once called Cincinnati home. “I miss all of them,” he says.