A 17-year-old white tiger was humanely euthanized after showing signs of age-related mobility issues, according to the Gladys Porter Zoo.

The tiger, Neb, had been with the zoo since 2008, according to a news release. Neb was one of six tiger cubs seized by authorities during an attempted wildlife trafficking operation at the parking lot of a Walmart. 

“They are living examples of the challenges posed by the exotic animal trade where inbred cubs are taken prematurely from their mothers for public tiger petting and photo ops,” the news release stated. “Since then, Neb has lived a comfortable life at the Gladys Porter Zoo, captivating visitors and raising awareness about tiger conservation.”

All tiger subspecies are listed as endangered or critically endangered by the International Union for the Conservation of Nature, the release added.

Neb began showing signs of age-related mobility issues within the past two years. Despite ongoing supportive care, his caretakers documented slower movements, increased reluctance to walk, and a more noticeable limp that was sometimes accompanied by weakness or a loss of balance, the release added.

According to Gladys Porter Zoo director Pat Burchfield, the life expectancy for tigers is 10 to 15 years.

“Neb was more than just an animal in our care; he was a symbol of resilience and hope,” Burchfield said in a statement. “Despite a rough start in life, his relative longevity is a testament to the wonderful care he received from our veterinary team and his keepers, who loved him dearly. He inspired an appreciation for his majestic species in countless visitors to our zoo.”

Zoo staff will monitor Neb’s companion, a 17-year-old female named Hobbes, who is also experiencing mobility issues. 

"She has, and will continue, to receive specialized care and medical attention to ensure her comfort into the future," the news release said. "Additionally, Hobbes’ animal care team is keeping a close eye on her well-being following the passing of Neb."