Beloved sea lion, called a 'chatty goofball,' dies at NC Zoo

Remembered by one zookeeper as a "chatty goofball full of energy," according to a press release, Diesel was anesthetized after the zoo's veterinary team saw that he was experiencing eye pain and some loss of appetite.

He had been successfully anesthetized for exams in the past, according to the zoo, but Diesel developed an abnormal breathing pattern during recovery from the procedure and went into cardiopulmonary arrest.

The team attempted resuscitation efforts, including CPR, but he passed away. A necropsy, or animal autopsy, and a full pathology report will provide more information about his cause of death in the coming weeks, according to the zoo.

"Diesel had a big sparkling personality," said Sally Adams, one of his zookeepers, in the release. "He epitomized what a California sea lion is. He was a chatty goofball full of energy, always eager to learn new things and show off anything new.”

Diesel arrived at the zoo in 2015 with another sea lion pup named Owen. Both had been deemed unfit to be return to the wild,

As a pup, Diesel had been found stranded on the beach in California and brought to a marine mammal rehabilitation center for care, according to the zoo. Once stable, he was released back into the wild. He stranded again shortly after release, prompting marine mammal rehabilitation experts to deem him unable to survive in the wild. He was then brought directly to the North Carolina Zoo in July 2015, the zoo's release says.

According to the zoo, California sea lions, who live along the western North America coastline from Alaska to Mexico, are known for their intelligence and playfulness and are very social animals. He was a favorite of guests and keepers because of his charismatic personality.

In the United States, the California sea lion is protected under the federal Marine Mammal Protection Act, passed in 1972, which outlaws hunting, killing, capture, and harassment of the animal, according to the zoo. They have thrived since the law was enacted. In the wild, sea lions can live up to 14 years.