MILWAUKEE -

A young orangutan at the Milwaukee County Zoo has died.

Zoo officials said 5-year-old Mahal died in his exhibit Saturday about 8:30 a.m. Zoo officials said he'd been showing signs of illness since Thursday.

The zoo's veterinary staff believes the cause of death was pneumonia. An official necropsy will be conducted to determine the exact cause.

Zoo officials said Mahal was especially popular with zoo visitors and they intend to plan a way for the public to commemorate him.

A Milwaukee Journal Sentinel report said the red-haired orangutan was born in Colorado in 2007 but his mother rejected him. Mahal was brought to Milwaukee to be raised by a surrogate mother.