The zoo asked the St. Louis region to keep Gabby's care team in their thoughts. Harbor seals have an estimated lifespan of 40 years in the wild, according to the National Park Service .

Gabby arrived at the Saint Louis Zoo in 2014, four years after she was born, zoo staff said. The 14-year-old harbor seal, named Gabby, will be "greatly missed" by zoo staff. Here's why.