Officials at an Oklahoma zoo are mourning the seemingly unexpected death a 27-year-old American alligator named Alli.

The Tulsa Zoo on Wednesday said in a statement that Alli died of a “severe reproductive infection that spread throughout her body.”

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The “feisty” reptile's death on July 10 surprised zookeepers as Alli “had been behaving normally and gave animal care staff no indication that she was ill.”

“Zookeepers cared for and respected Alli, who they fondly remember as a feisty animal,” zoo officials said, adding the gator “commanded attention from her caretakers, and even from nature.”

Alli would “bellow back at the thunder” during spring storms, and “proved to be a quick learner, readily picking up new behaviors and adjusting to changes in routine.”

“She was always the first to shift into the winter holding, and always the first to come out," the zoo added.

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The gator first arrived at the Tulsa Zoo in 2009 from the Roosevelt Park Zoo in North Dakota. She lived with a male American alligator — Gus — for 10 years prior to her death.

The American alligator — once an endangered species — can be found throughout the southeastern part of the country, “from the Carolinas to Texas and north to the southeast corner of Oklahoma,” per the Tulsa Zoo.