Ahpun the polar bear dies after nearly 20 years at Alaska Zoo

The zookeeper found Ahpun the polar bear dead during morning rounds Sunday.

Orphaned in 1998 as a cub, Ahpun was found dead by a zookeeper on Sunday

In this Sept. 5, 2012, file photo, Ahpun, a female polar bear, strolls around her cage at the Alaska Zoo in Anchorage, Alaska. The popular polar bear died unexpectedly on New Year's Eve the zoo said Tuesday, Jan. 2, 2018. (Dan Joling/AP)

A beloved polar bear at the Alaska Zoo in Anchorage has died.

A zookeeper found Ahpun, who was about 20 years old, dead during morning rounds Sunday.

Zoo director Patrick Lampi says Ahpun had shown no signs of illness and a necropsy found no cause of death. Tissue will be sent out for additional analysis.

Ahpun was orphaned in 1998 near Point Lay on Alaska's northwest coast. A man returning from a fishing trip unknowingly approached a den and Ahpun's mother charged.

The fisherman shot the bear in self-defence and determined she had emerged from a den. The fisherman crawled inside and found the cub.

Ahpun grew from a 14-kilogram cub into a 317-kilogram adult.

The zoo also has a male polar bear, nicknamed Louie.