Bubbles, a female pilot whale at SeaWorld in
"SeaWorld San Diego is saddened to announce the passing of one of the world's most beloved animals, Bubbles the pilot whale," the company said on its website.
A necropsy is planned to determine the cause of death. The company, which operates marine parks in San Diego, San Antonio, Texas, and Orlando, Florida, did not say when she died.
Pilots whales, which have rounded heads and mouthlines that curve upward to resemble a smile, are in the dolphin family and are smaller than orcas, or killer whales.
Pilots, which live in pods of 20 or 90 animals, are about as intelligent as dolphins and easily trained, according to the American Cetacean Society.
Weighing roughly 3,000 pounds (1,360 kg) and measuring 15 feet (5 meters) long, Bubbles was considered the "grande dame" of SeaWorld. She was known for her ability to jump out of the water and spin at great velocity.
SeaWorld has faced intense public scrutiny over its public display of marine animals, especially killer whales.
In March, the company said it would stop breeding killer whales in captivity, but would still put on performances with orcas at its three parks.