CHICAGO, June 12 (UPI) -- A chimpanzee at Chicago's Lincoln Park Zoo is set to celebrate his 50th birthday while on public view for the first time in four years, zoo officials said.
Keo the chimp was moved into a public display this week at the zoo's Regenstein Center for African Apes after spending most of the last four years in a habitat out of public view, the Chicago-Sun Times reported.
Keo's 50th birthday is June 26.
Zoo workers say the 5-foot tall, 117-pound chimp is "a very congenial guy" and is in healthy condition with only slight arthritis in one finger.
Keo has had two mates and sired 11 offspring, but now has undergone a vasectomy, even though the chip "still has it in him," researcher Steve Ross said.