If you’ve been to the Zoo in the last 40 years, you’ve probably crossed paths with Zookeeper Silvia Zirkelbach. You can usually find her near the giraffe area with her auburn hair tied back, wearing a silver necklace featuring a woolly monkey shaped pendant. It’s easy to tell how much Silvia loves her animals; when she talks about them, her whole face lights up.
Silvia is a bit of a rarity to the Louisville Zoo: she’s one of the few keepers who has worked in one area of the Zoo during her entire career with us. First a Zoo volunteer in the Africa/giraffe area, she then moved to become a Zoo keeper in the same area — and stayed there! “I was happy where I was,” Silvia said. “I had a degree in zoology; I had worked on a farm with horses. It just made sense that I would move into taking care of zebras and giraffes — they’re just a little wilder than the animals I already worked with and loved.”
Back when Silvia started, the giraffe area was a bit different than it is now. The Louisville Zoo didn’t have an Islands exhibit or a HerpAquarium yet. So, there were a variety of animals under Silvia’s watchful eye — hoofed animals, some carnivores like big cats, birds, reptiles and even some primates like orangutans. Silvia spent a lot of time caring for smaller primates and her talent for their care was evident. Of the approximately 25 animals born at the Zoo that Silvia personally hand-raised, 7 of those were woolly monkeys. “I believe I’ve raised more woollies than any other human in the United States,” Silvia said, laughing.
Silvia’s passion for animals has certainly given her an exciting career. She traveled to Columbia near the border of Brazil for three weeks with researchers and experts in forest ecosystems to study the wildlife. Staying in wood and tin roof cabins at the conservation center there, she observed the wildlife and primates, learning about the struggles they face in the vanishing wild. “It helped me to understand more about their behavior and also made me feel even more passionate about protecting them,” she said.
Her passion has made a significant impact on the care of primates in managed systems. Woolly monkeys, like people, can develop hypertension. Silvia, along with Louisville Zoo veterinarians, were determined to find a way to monitor the health more closely to potentially treat these precious primates. With Silvia’s urging, a training method was developed to train them to let keepers take their blood pressure.
Unlike today, smaller primates in the 80s did not participate in regular training to actively participate in preventative healthcare. With Silvia’s help and expertise in training using operant conditioning (as well as yummy grapes and a handy whistle), the woollies learned to present their tail (and later their arm) for Silvia to apply a blood pressure cuff. In fact, Silvia was one of the first zoo keepers to measure resting blood pressure from a nonhuman primate! What an incredible achievement and significant innovation in primate care.
Keepers and vets in AZA-accredited Zoos in North America now commonly utilize this technique to test blood pressure of primates. Silvia gets calls occasionally from facilities across the world asking for her advice on their woolly monkey issues.
Silvia says some of her most treasured moments come from the many animals she hand-raised over the years. “It’s so rewarding to watch them grow up!” she said. But like most rewarding experiences — it wasn’t always an easy task. Silvia recalls a giraffe named Silvester that was born on her birthday to Malaika, but Malaika wasn’t interested in mothering him. “He refused to take a bottle and wouldn’t let any of us touch him.”
Anxious for the future of this stubborn giraffe calf, Silvia did the only thing she could think of: “I was desperate. I set up a step ladder that night and climbed to the top of the ladder and just sat there with him for hours talking to him and hoping he would get comfortable with me. Finally, after a long time, he came over and let me touch him. Then, he took a bottle from me. I came to find out later that he preferred drinking milk from a bucket — and so that’s what he did from then on mostly.”
Nowadays, Silvia is still doing what she does best — taking care of animals in the Africa zone like the giraffes and woolly monkey, Tomas. The retired primate is not viewable to the public but enjoys both indoor and outdoor spaces where he can climb, munch and explore while receiving specialized attention. If you see Silvia, be sure to wave and thank her for her dedication!