When 19-year-old chimpanzee Sile gave birth to her first baby at Rockhampton Zoo in central Queensland this past June, it should have been a joyful milestone. Instead, within hours, the newborn chimpanzee was accidentally dropped by her inexperienced mother and suffered a fractured femur.
What followed was months of round-the-clock human care, a tiny chimp in a cast who captured the attention of the local community, a heartbreaking setback during a reunion attempt — and now, a new opportunity for Cassie to learn how to live as part of a chimpanzee troop.
A Rocky Start
Zoo staff acted quickly when they realized what had happened. The newborn was taken for X-rays and fitted with a small cast to help her recover from the serious leg injury.
The baby was later named Cassie. Her name honors Cassius, a much-loved chimpanzee who lived at Rockhampton Zoo for nearly 40 years, as well as a local woman named Cassie who donated colostrum to help the newborn.
Zoo curator Blair Chapman explained that hand-raising a baby chimpanzee is an absolute last resort. But with Cassie’s broken femur, keepers had to step in and provide the intensive care she needed.
Cassie was bottle-fed roughly every three hours and received constant attention from her keepers. To give her something resembling the comfort and contact of another chimpanzee, a keeper and her mother even made special “chimp vests” that Cassie could cling to.
Despite her difficult beginning, Cassie continued to grow and recover.
Her keepers also worked hard to keep her connected to chimpanzee life. She was housed close to the main chimpanzee habitat, where she could vocalize with the troop through the mesh. She was also able to watch her father, Alon, as he displayed and interacted nearby.
A Reunion That Didn’t Go as Planned
Once Cassie’s leg had healed, the team carefully explored whether she could return to her mother and the other chimpanzees at Rockhampton.
Unfortunately, the reunion attempts did not go as hoped.
Cassie was introduced to her mother, Sile, and another adult female named Mary. Both females displayed aggression toward the youngster, and Cassie suffered bruising and bite marks.
For the keepers who had spent months caring for her, it was a heartbreaking setback.
But the problem was bigger than simply finding a way to keep Cassie safe. Chimpanzees are highly social animals, and Cassie needed the opportunity to grow up learning normal chimpanzee social behaviors from other chimpanzees.
Primate team leader Jo Thrower explained that remaining in human care indefinitely could create problems for Cassie later because she could become too accustomed to people rather than chimpanzees.
That meant the team needed to find another troop where Cassie could have a realistic opportunity to develop those important social relationships.
A New Home, 2,000 Kilometres Away
In September, Rockhampton Zoo and Zoos South Australia announced that Cassie’s next chapter would take her to Monarto Safari Park, south of Adelaide.
There, she will have the opportunity to gradually meet an established troop of 12 chimpanzees ranging in age from 3 to 47.
Monarto’s team has experience with hand-rearing, surrogacy and carefully managed introductions. Keepers from both zoos will be involved in the transfer and will help oversee Cassie’s transition.
But Cassie will not simply arrive and immediately be placed into the troop.
After her planned move in early October, she will first have time to settle into her new surroundings and become familiar with her new caretakers. Any introductions to the other chimpanzees will happen gradually and will depend on how Cassie and the troop respond to one another.
“Human care has been incredibly important for Cassie, but ultimately it’s essential that she has the chance to learn from other chimpanzees.”
That opportunity is exactly what the team hopes Cassie will find at Monarto.
A New Chapter for Cassie
Cassie’s journey has already been extraordinary.
She entered the world with a difficult start, suffered a serious injury within hours of birth, and then spent months depending on human caregivers while recovering. She later faced another setback when attempts to reunite her with chimpanzees at Rockhampton did not succeed.
Now she has another chance.
Her move to Monarto Safari Park is not the end of Cassie’s story, and nobody can yet say exactly how quickly she will bond with her new chimpanzee companions. But the move gives her something she needs: the opportunity to learn, socialize and build relationships with other chimpanzees.
For the keepers and community members who have followed Cassie’s journey from a tiny newborn in a cast, saying goodbye will be bittersweet.
But perhaps the most important part of Cassie’s story is what comes next.
She is getting the chance to discover her chimpanzee family.
And for this little survivor, that could be the beginning of a very special new chapter.
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