An Alaskan sea otter that survived the Exxon-Valdez oil spill in 1989 has passed away at Chicago’s Shedd Aquarium, officials said Wednesday.

Shedd Aquarium executive vice president of animal care and training Ken Ramirez said the otter, Kenai, was 23-years old—long past the median life expectancy age of 15 to 18. He said she was euthanized after caretakers determined her recent pain could not be permanently cured.

Ramirez said he cared for the animal as a pup after the oil spill and, in a phone interview Wednesday, he recalled a gentle creature and a “true survivor.”

“I’ve never known another animal that has come back from so many hardships and so many serious challenges in her life,” he said, adding that he had “made a special place” in his heart for the animal.

“What I loved most was how much she enjoyed being carried. And she would take her little paws and put them behind your neck and pull your face toward yours because she liked the smell of your shampoo or your mouthwash or your deodorant that you were wearing.”

In a statement, Shedd officials said Kenai suffered from arthritis and cataracts. The otter also needed dental work on a cracked tooth in 2010, the statement said.

Kenai had also experienced “a massive and quite serious stroke” which, Ramirez said, had her caregivers greatly worried for her health.

But Ramirez said Kenai’s aging process also possibly contributed to furthering knowledge of sea otters.

“There’s been so few sea otters that have lived to this age, it’s hard to some times know if what we are seeing and the many things that we have learned are unique to her or will they become a trend,” Ramirez said.

He said science will need to examine more otters with these life spans in order to understand more about them.

Shedd Aquarium officials said one other surviving otter from the 1989 oil spill is in Point Defiance Zoo and Aquarium in Tacoma, Wash.

According to the official aquarium statement, the disaster in Point William Sound in Alaska “immediately” claimed the lives of 2,000 sea otters.