Halloween Eve. A chill shivers the air, rustling the petals of the Cincinnati Zoo and Botanical Garden’s columbines, milkweeds, and asters. Harapan, the only Sumatran rhino in the western hemisphere, sniffs the lingering scents of giant pretzels for the last time. Today, he leaves for a reserve in Sumatra, a tropical island in the Indo-Pacific, where he will join other members of his rapidly vanishing species: less than 100 Sumatran rhinos remain.

Since the beginning of efforts to prolong the Sumatran rhino’s existence, the Cincinnati Zoo has been deeply involved. Beginning In 1984, poaching became a common tale. Sumatran jungles were vanishing in favor of clearing agricultural land, and its rhinos were suffering tremendously in the process, faced with fragmented territory and a growing market for their horns. So, 40 rhinos were captured and sent to zoos across the world to establish a captive breeding program. The Cincinnati Zoo was one of these. At first, the program seemed simple enough. Scientific papers detailing the behavior of Sumatran rhinos flooded journals and new conservation ideas flowed from abstract theory into implemented concepts. Despite all this, by the late 90s, no Sumatran rhinos had been born in captivity. But in 2001 the birth of Andalus at the Cincinnati Zoo cast a sudden heat in the international fever to preserve the Sumatran rhino. Andalus was followed by two siblings, Suci and Harapan. In 2007 he was sent to the Sumatran Rhino Sanctuary (SRS), where Harapan is now.

Although Harapan is quite possibly the last Sumatran Rhino to stand on this half of the world, the Cincinnati Zoo’s research continues to be vital for the species. Their cryobank preserves Sumatran Rhino DNA, and in the Cincinnati Museum Center stands Ipuh, the Cincinnati Zoo’s first Sumatran rhino, as a lasting testament to their efforts.

While at this moment Harapan and Andalus are probably cooling off in the Sumatran mud pools, the Cincinnati Zoo manages a different program for another critically endangered species: the bonobo.

Our closest living relatives, with dark faces and a curious glint in their eyes, hail from the Congo. Similarly to the Sumatran rhino, deforestation has brought them a host of issues. While they don’t live in clearly established territories like chimpanzees, they do enjoy extremely social lives in the wild that are hard to mimic in captivity. Shortly after Harapan’s departure, the Cincinnati Zoo experimented with what they have dubbed the “Super Troop.” For one week, all of their bonobos were grouped together in the indoor exhibit. I got the chance to see the “Super Troop” myself, and watched two of the bonobos groom each other among the branches. This is typical social behavior, equivalent to the norm of humans eating dinner together. As the adults were picking the tangled knots out of each others’ long, black hair, one of the infants toddled away from its mother and watched two juveniles swing past. It held one of the tree branches tentatively, considering whether to join them. After a moment’s contemplation, it released the branch and returned to its mom. Meanwhile, Lana, a 36-year-old fresh from the San Diego Zoo, greeted curious children with faces pressed against the windows. These scenes occurred constantly, garnering laughter, intrigue, and, as is the goal of the “Super Troop”, a new light into what we currently know about bonobo social behavior.

The Cincinnati Zoo is one of only 7 zoos in America with bonobos and has already seen the birth of 10. There is currently a captive population in America of roughly 90 individuals, and 11 of them reside right here. Because they live so deep in the Congo – one of the least explored places in the world – it is impossible to give their population size, but estimates range from 29,500 to 50,000.

While these numbers make the Sumatran rhino’s situation seem far bleaker than the bonobo’s, their population’s recovery wouldn’t be the first miracle for pachyderms. In the early 1900s, less than 50 Southern White Rhinos were in existence, but now, they boast a healthy, genetically diverse population of over 20,000. With all the research from the Cincinnati Zoo and other facilities, conservationists remain hopeful.

Bonobos and Sumatran rhinos aren’t the only endangered and vulnerable species the Zoo is helping. They also have very successful programs in place for river otters, red pandas, painted dogs, gorillas, black and Indian rhinos, ocelots, fishing cats and bees. Extinction may be a permanent sentence, but so may be the zoo’s strong stance against it.

Further Reading:

For details about Harapan’s journey from Cincinnati to Sumatra: http://cincinnatizoo.org/blog/2015/11/02/rhino-harry-arrives-safe-and-sound-after-53-hour-journey-from-cincinnati-zoo-to-sumatran-rhino-sanctuary/

For information about the history of the Sumatran Rhino Conservation Program and its future:

http://www.rhinos.org/where-we-work/sumatran-rhino-conservation-program/

For bonobo facts and videos:

http://cincinnatizoo.org/blog/animals/bonobo/

For details about CREW, the group behind the success of the Sumatran Rhino Conservation Program in Cincinnati, and their future projects:

http://cincinnatizoo.org/conservation/crew/