When Regenstein Center for African Apes reopens, guests might spot new combinations of chimpanzees on any given day—including individuals who usually thrive behind the scenes.
The next time you visit Regenstein Center for African Apes, things will be a little different. And the time after that? Well, that depends on the chimpanzees.
For the past 15 years, male chimpanzee Hank’s group has flourished in view of guests while another group thrived in a behind-the-scenes habitat with its own private outdoor space. But once the building reopens to the public, guests might see new combinations of chimpanzees in the front-of-scenes habitat on any given day—and that fluidity might not change any time soon.
“Chimps themselves are biologically flexible,” says Stephen Ross, Ph.D., director of the Lester E. Fisher Center for the Study and Conservation of Apes. “In the wild, they don’t live in static groups that stay the same over the course of their lifetime. That dynamic inspired the flexibility and design of the building, allowing us to appropriately care for this species at Lincoln Park Zoo.”
Caring for Fission-fusion Species
As a fission-fusion species, chimpanzees naturally splinter and merge into different social groups over time. This fluidity has always existed at Regenstein Center for African Apes, albeit to a smaller degree. Although guests have mostly only seen Hank’s group, many of the individual chimpanzees have “met” behind the scenes, sometimes in an off-exhibit space that prevents physical contact but allows them to get to know each other through sight, smell, and sound.
“We always knew that, at some point, we might need to get creative and flexible with the group compositions,” says Curator of Primates Jill Moyse. “This idea might go counter to what people usually think of in term of zoos. People think, ‘here’s an exhibit and here’s the group,’ and that’s the group they expect to see when they visit next time. But there’s a lot of more that goes into caring for these species, and different species have different needs.”
Staff from across the zoo—from curators and veterinarians to researchers and animal welfare scientists—will all collaborate in order to guide the formation of each group. Ultimately, however, the chimps will have final say on both the pace and the final composition.
A longtime partnership with Chimp Haven, a national chimp sanctuary that introduces dozens of new chimps each year, and Ross’ role with the Chimpanzee Species Survival Plan® provide Lincoln Park Zoo with valuable insight into the introduction process. But even with all that information, it’s impossible to predict exactly how two chimpanzees–let alone five or six–will react during their first encounter.
“Chimpanzees don’t always act the same, depending on who they’re with,” Moyse says. “Eventually, you have to put them together based on what they’re telling you they’re comfortable with and then hope for the best. Sometimes, they surprise you in a good way. Sometimes, you have to try again, but you gained some valuable knowledge that will inform
your next step.”
Moyse and Ross hope to eventually form new “healthy and stable” groups. However, they stressed that the decision on timing isn’t really up to them.
“At the end of the day, we’ll do whatever it takes to set the animals up for success,” Ross says.
Considering Atypical Backgrounds
Historically, many of the chimpanzees living in the off-exhibit space have had atypical backgrounds or required special attention because of that history or other factors, such as age. Some were pets, and others came from the entertainment industry or labs.
“In a lot of cases, these individuals were learning how to be chimps for the first time,” Ross says.
The off-exhibit space, according to Moyse, has given these individuals the chance to learn species-specific skills— and sometimes meet other chimpanzees for the first time—in a more private area.
For example, guests have rarely seen Kibali, whose arm was amputated due to an injury. Since the surgery, she has adapted well by learning new behaviors in the off-exhibit space. The building’s newest residents, Eli and Susie, were rescued from an unaccredited sanctuary through Project ChimpCARE and arrived at Lincoln Park Zoo in spring 2020. Another historically off-exhibit chimpanzee, Cookie, was also rescued through the initiative after being born in a lab.
Project ChimpCARE was founded by Ross in 2007 to improve the welfare of all 1,300+ chimpanzees currently living in the United States. Through the initiative, he has conducted a nationwide census to find every chimpanzee in the United States, facilitated efforts to rehome former pet and performing chimpanzees to accredited sanctuaries and zoos, and played a role in enhancing protections for chimpanzees by including them as species protected under the Endangered Species Act.
Thanks to these efforts, he actually learned about Eli and Susie more than a decade ago and was eager to work with Lincoln Park Zoo and the Association of Zoos and Aquariums (AZA) when the opportunity arose to rehome the chimpanzees to a more appropriate and stable home. According to Ross and Moyse, they will know they’ve succeeded in creating new chimpanzee groups when every individual at the zoo can coexist in a natural manner. That doesn’t mean eliminating aggression—a perfectly normal behavior for the species—but balancing that with relaxed social behaviors.
“Even Hank and Optimus, the males in the other group, they still have their squabbles even after all these years,” Moyse says. “But they always eventually reconcile and make peace with each other. When we get to that point with all the chimps in each group, especially among some of the historically off-exhibit chimps, that will be a success.”