HUTCHINSON, Kan. – [October 20, 2026]- Hutchinson Zoo staff mourn the loss of Sioux, the oldest member of the Zoo’s bison herd and matriarch.
Sioux joined Hutchinson Zoo in 1999 and became a steadfast presence in the herd. Named in honor of the Sioux people, she was the mother of six and the grandmother of one of the bison that have lived at the Zoo over the past 27 years.
With an average life expectancy of 15-20 years, Sioux lived long enough to become the oldest bison in human care at an Association of Zoos and Aquariums (AZA)-accredited facility.
In recent months, Sioux was under close quality-of-life observation because of arthritic changes in her body. Animal care staff monitored her carefully for additional symptoms and changes in her comfort and mobility. When other symptoms began to affect her quality of life, the difficult decision was made to humanely euthanize Sioux. Post-mortem testing later confirmed that Sioux had cancer, which caused further complications.
“Our staff cares deeply about all the animals they work with every day, and Sioux was one of their favorites,” said Nicole Mantz, Zoo Director. “She was mischievous and daring as a younger bison, and even in her later years, she remained spirited.” Keepers note that as her care became more in-depth with age, Sioux was usually the best at training and was very cooperative with her health care needs. “We are honored to have cared for her for so long, and she will be truly missed.”
Sioux played a key role in shaping the bison program at the Hutchinson Zoo on its current site in Carey Park. When Sioux first arrived, the zoo housed bison and deer in a central exhibit called “Horn and Antler.” They later moved across the pond, where Sioux and her herd taught keepers that they could swim over the barriers in the water and enter the rest of the Zoo. Safety measures were put in place, and guests viewed them from across the pond until 2024, when the Dan and Shirley Power Family Bison Viewing area opened. There, guests could meet Sioux and her family up close and feed them. Two of her daughters remain, Sitsi, 22, and Annie, 19.
Hutchinson Zoo is committed to bison conservation and will continue to support the AZA American Bison SAFE program. SAFE—Saving Animals from Extinction—brings AZA-accredited institutions and conservation partners together to help protect and sustain bison populations. As the Zoo’s flagship species, bison will remain central to Hutchinson Zoo’s conservation, education, and animal-care efforts for years to come. Staff is working with AZA Bison program leaders to add more bison to the herd in the future.
The Hutchinson Zoo thanks the animal care and veterinary team for their compassionate, dedicated care of Sioux throughout her extraordinary life.
