Weather Updates

Oldest male chimp in North America dies at Lincoln Park Zoo

Keo was 55 years old. He was oldest living male chimpanzee any North American zoo very first chimpanzee live Lincoln

Keo was 55 years old. He was the oldest living male chimpanzee in any North American zoo, and the very first chimpanzee to live at Lincoln Park Zoo. He arrived in Chicago in 1959 when he was just one year old and sired 11 offspring over the years. | Lincoln Park Zoo photos

storyidforme: 55795113
tmspicid: 20435033
fileheaderid: 9482204

Updated: November 2, 2013 6:20AM

If chimps could talk, they probably would have asked Keo how he lived so long.

The chimp was 55 when staff at the Lincoln Park Zoo euthanized him Monday morning due to advanced cardiac disease.

Keo was the oldest male chimp at any zoo in North America, according to Lincoln Park officials.

The average life span for male chimps in zoos is 31.7 years, said Dr. Steve Ross, director of the zoo’s Lester E. Fisher Center for the Study and Conservation of Apes. The life expectancy is about the same for chimps in the wild, he said.

Ross attributed Keo’s longevity to the strong bond he had with zoo staff and the veterinary care he received.

“I’ve seen chimps 10 or 15 years younger than him that didn’t have the same vitality,” said Ross, who noted Keo was swinging from stuff and climbing to heights of 20 feet just a week before his death.

The oldest male chimp on record died a few years ago at the age of 62 at the Sequoia Park Zoo in California. His name was Bill.

“Keo was born in the wild, which is rare now [for chimps in captivity],” said Ross, who noted that chimps are currently bred instead of taken from the wild.

Keo was a highly social chimp who sired 11 offspring and took part in research using touch-screen computers and tools, Ross said.

“People with painted nails would come visit him and he always wanted to check that out, he was a very curious guy,” Ross said.

“All the keepers here are very upset, as are the research staff,” Ross said. “Keo has touched the lives of literally thousands of people.”

Keo, who had not been on exhibit since last summer, came to the Lincoln Park Zoo at the age of one in 1959. He was caught somewhere in Africa, Ross said.

An autopsy will be performed on Keo to advance the treatment of heart disease. His body will then be cremated, Ross said.

Visitors to the Lincoln Park Zoo can sign a card for Keo or go to the memorial page on the zoo’s website to leave a comment.


Twitter: @mitchdudek

© 2014 Sun-Times Media, LLC. All rights reserved. This material may not be copied or distributed without permission. For more information about reprints and permissions, visit To order a reprint of this article, click here.