To minimise risk to the staff in case the chimpanzees unexpectedly wake up, they’re fitted with secondary restraints as an extra precaution, thick chains and belts around their ankles.
Even for regular procedures like this, experience and knowledge make everything run smoothly and, having worked at the zoo for 30 years, Dr Vogelnest has been there when things didn’t quite go to plan.
He described a moment from about 15 years ago when a chimpanzee woke up during a medical procedure.
The animal sat up, looked around and, to the relief of the vets and keepers in the room, fell back to sleep.
“I think out of all the great apes they’re probably, to me anyway, the most human-like because they have all those sorts of [traits such as] caring, compassion, aggression, craziness, politics that they follow, that people have. So they’re just fascinating animals like that,” Dr Vogelnest said.
The primates are so close to humans the same contraception methods are used on them.
Kuma was fitted with a new contraceptive implant, the same kind that’s used by doctors for their human patients, in her upper left arm.
The good news is that both chimps passed the health check and are fine.
The biggest concern for the animals is the group dynamics that acting primate unit supervisor Laura Fidler says are “critically important”.
“They’ve got multi-male, multi-female, they’re very much like a wild group and that means that they’re political, they’re strategic, they can be aggressive, they can be playful, caring, everything that you’d see across the whole range of behaviours,” she said.
Following the procedures at the zoo, Kuma and Fumo spent the night together apart from the others. They were reintroduced to their enclosure the next day.
This can be a challenging time, Ms Fidler said, as animals see an opportunity to start to assert their dominance and a power play over hierarchy can begin.
It’s trickier to reintroduce a very low-ranking animal to the group than a very dominant animal, Dr Vogelnest said.
“The dominant animal will just go in there, whereas a low ranking animal usually gets picked on.”
Kuma, who weighs 89.3 kilograms, is a highly ranked female and the keepers aren’t concerned about her reintroduction.
“She’s a very large female and, you know, in size and personality, so nobody really wants to mess with Kumar because you get in trouble if you do.”
And Fumo gets his mother’s protection, so there’s no trouble for him either.
Audio/Video Journalist at The Sydney Morning Herald