HUTCHINSON, Kan. — The Hutchinson Zoo is mourning the loss of Sioux, the oldest member of its bison herd and a longtime fixture at the zoo.
Sioux arrived at the Hutchinson Zoo in 1999 and spent 27 years helping shape the zoo’s bison program. She was the mother of six and grandmother of one of the bison that have lived at the zoo during that time.
Zoo officials said Sioux lived well beyond the average bison life expectancy of 15 to 20 years and became the oldest bison in human care at an Association of Zoos and Aquariums-accredited facility.
In recent months, animal care staff closely monitored Sioux as arthritic changes affected her mobility. When additional symptoms began affecting her quality of life, staff made the decision to humanely euthanize her. Post-mortem testing later confirmed Sioux had cancer, which had caused further complications.
“Our staff cares deeply about all the animals they work with every day, and Sioux was one of their favorites,” Zoo Director Nicole Mantz said. “She was mischievous and daring as a younger bison, and even in her later years, she remained spirited.”
Keepers said Sioux became particularly cooperative with training and health care as her needs increased with age.
Sioux was also part of the evolution of the zoo’s bison exhibits. When she first arrived, bison and deer were housed in the central “Horn and Antler” exhibit. The bison were later moved across the pond, where Sioux and the herd surprised keepers by demonstrating they could swim across barriers and enter other areas of the zoo.
Additional safety measures were eventually installed. In 2024, the Dan and Shirley Power Family Bison Viewing area opened, allowing visitors to see Sioux and her family up close and feed the animals.
Two of Sioux’s daughters remain at the zoo — 22-year-old Sitsi and 19-year-old Annie.
The Hutchinson Zoo said it remains committed to bison conservation through the AZA American Bison SAFE, or Saving Animals from Extinction, program. Zoo staff are also working with AZA bison program leaders on plans to add more bison to the herd in the future.
Zoo officials are inviting community members who remember Sioux to celebrate her life by sharing photographs, stories and favorite memories of the longtime bison matriarch.