OKLAHOMA CITY (KFOR) – The Oklahoma City Zoo and Botanical Garden says its 22-year-old female American bison, Mary Ann, was humanely euthanized Tuesday.

Mary Ann arrived at the OKC Zoo in 2001 from Sedgwick County Zoo in Wichita, Kansas, and was one of the first species to relocate to the zoo’s Oklahoma Trails habitat when it opened in 2007.

Zoo officials say Mary Ann was considered a geriatric animal at 22 and showing signs of decline from age-related issues. More recently, she was experiencing decrease of appetite and increased respiratory effort, compromising her quality of life, according to her care team.

The decision to humanely euthanize her was made when it became clear to caretakers that medications and treatment were no longer helping.

“Caring for Mary Ann was a joy and privilege for myself and the entire team,” said Tracey Dolphin, OKC Zoo’s curator of hoofstock and primates. “She brought smiles to guests of all ages through experiences like our Wild Encounters and annual enrichment activities, and will be missed by many.”

According to Mary Ann’s caretakers, she was a fan of foraging for food and interacting with enrichment – particularly cedar trees, and would enthusiastically rub her head and body on the tree branches.

Mary Ann the bison
Mary Ann. Image Dr. Andrea J./OKC Zoo.

The OKC Zoo is home to two other bison, 3-year-olds Yarrow and Verbena.

Just 200 years ago, there were over 30 million bison roaming the United States. However, they were nearly hunted to extinction by the late 1800s before being brought back from the brink by a herd released in 1907 on what is now known as the Wichita Mountains National Wildlife Refuge.

Bison are currently listed as near threatened by the International Union for Conservation of Nature.

For more information or to buy tickets, visit the OKC Zoo’s website.