Keo Memorial

Lincoln Park Zoo Bids Sad Farewell to Beloved Chimpanzee

Keo, 55, was one of the country’s oldest chimps

(Chicago, Sep. 30, 2013) -- Lincoln Park Zoo is deeply saddened to report that animal care staff made the difficult decision on September 30 to euthanize Keo, a geriatric male chimpanzee, after advanced cardiac disease compromised his quality of life. 

Keo was 55 years old. He was the oldest living male chimpanzee in any North American zoo. He arrived in Chicago in 1959 when he was just one year old and sired 11 offspring over the years.

“Keo was an incredibly special individual. He was truly a member of our family and will be missed dearly,” said Curator of Primates Maureen Leahy. “His long, rich life is a testament to the wonderful care he received here as well as the veterinary advancements that have been made in the past five decades.”

The median life expectancy for male chimpanzees living in zoos is 31.7 years. The maximum longevity record is 61 years.

For the final years of his life, Keo lived predominantly behind the scenes at Regenstein Center for African Apes with two female chimpanzees, Vicky, and her daughter, Kibali.

“Keo was always full of personality, even as his health began to decline,” said Director of the Lester E. Fisher Center for the Study and Conservation of Apes Steve Ross, PhD, who is the director of the Chimpanzee Species Survival Plan (SSP), “I can speak for everyone who knew Keo when I say his loss is felt keenly, and working with him was a privilege that we will all treasure forever.”

Lincoln Park Zoo works to conserve chimpanzees through research conservation efforts in Goualougo Triangle, Republic of Congo and Gombe National Park, Tanzania. Project ChimpCARE, headquartered at Lincoln Park Zoo, is aimed at addressing chimpanzee welfare and conservation concerns across the U.S. The zoo also supports the Chimpanzee Species Survival Plan which helps ensure that the chimpanzee population in zoos throughout the country remains healthy. 

Keo was a beloved individual and ambassador for his wild brethren. The Lincoln Park Zoo family is saddened by his loss. A memorial page has been set up in his honor, and Keo fans and friends of the zoo are welcome to leave comments, share memories, or express condolences to animal care staff who are especially affected by his loss. 

See Some of Our Favorite Keo Stories, Photos and Videos

Click here to download MPEG-4 video. (.MPEG, 68MB)
Click a thumbnail below to download full size version.



Thanks to everyone for sharing their heartfelt Keo memories. We've enjoyed reading them, and they've been a source of comfort for everyone at Lincoln Park Zoo.

While I wasnt fortunate enough to meet Keo, I would like to extend my sympathies to the zoo staff in your mourning and recovery process. I cannot imagine parting with such a beloved friend after so long. Keo passed the same day my cat of 12 years passed away, and my hope is that like all animals who have been euthanized they will be waiting for us when we have made the long trip back to them at the end of this life.

I met Keo two years ago as part of the ECG monitoring project, to detect arrhythmias in the chimps. I loved this guy at once. I will miss him, and am so sorry to see him gone. May God bless him and keep him among his blessed. He had a good life at LPZ, and contributed to our cardiac arrhythmia study project. The LPZ vets are the best in the world, and kept this old man alive for many years past his natural life expectancy. Many kudos to the curators and the vets that monitored and were friends with him for 55 years!

I only knew you a short while,but I am going to miss you. Rest in Peace old friend

Keo was such a wonderful character. I will miss sharing the hand to hand greeting we often had at the glass or showing him the completely amazing summer sandals with the miraculous Velcro fastenings or the pouting when one had not greeted him in the acceptable (to him) manner. There will never be another Keo. He was one of a kind!

One day we were privileged to visit RCAA when Keo and his group were in the public exhibits. He had gone outdoors into the yard, and I was outside too behind the screen, so I called his name. He turned at once and looked directly at me. What a feeling! He encouraged us to learn more about chimps and contribute to their care. His caregivers can be proud.

May you rest in peace and you lived a good life. You will be missed by many who have seen you.

I've never known Keo but I felt sad when I heard of the very sad news

I'd known Keo since 1985, when I started volunteering at LPZ. He brought so much joy and love to so many primates - human and chimp. Thanks to the entire zoo staff who cared so well for him throughout the years. I am as heartbroken as you are.
Rest in Peace, dear friend. I hope that there's many polished toenails in the hereafter.

So very sorry for your loss.

My thoughts and prayers to all the keepers who made this chimps life special some would say that he made their life and work special such is the bond between us and our closet cousin . May chimps always be among us for we are blessed by them being here may we treasure them always .Thank You LPZ

I had the privilege of meeting Keo for the first time a few months ago, and he left a lasting impression - such a vibrant and handsome chimp! My condolences to LPZ and everyone lucky enough to work with him.

I think it is amazing that there are such good people out there still in the world that care for animals, as we all should. This is a true testimony of people doing good things for the creatures of this health. Great Job Lincoln Park Zoo & sorry for your loss.

RIP great one you will truly be missed. You brought joy to many people over the years and lived a good long life thanks to the love & care you were shown in return.

Thanks to everyone for their heartfelt comments. The support is really appreciated during this tough time.

So sorry for your loss. He looks like a great chimp.

You were a teacher and source of joy to so many of us. I'm so fortunate to have had the chance to get to know you. May you be at peace wherever you are. Love always from countless human and animal hearts.

I really had hoped to meet him one day, I have Lincoln Park Zoo on my Facebook page..Someday I hope to visit Rest in Chimp Heaven Keo ♥ †

My friends , all of us who worked for Cafe Brauer concessions in the Mid 70's to mid 80's had a oportunitty to see our friend Keo everyday. What a character he was.He would become as excited to see us as we would to interact with him. We would spend time with him in the mornings when there were'nt many people in the zoo. But he would recognize us as we passed thru out the day. Even now thirty years later we all still talk about Keo , everytime we get together. We lost a friend . Thanks Keo for being a part of our lives.

"But he would recognize us as we passed thru out the day"

Bob the same thing happened to me once on a Saturday when I was visiting the zoo. There was a decent size crowd being entertained by him and then Keo stopped playing around and acknowledged me, and my girlfriend said wow he recognizes you. He gave so many people great memories.

I am sure that it was a very difficult day at Lincoln Park Zoo, Keo was one of my grandfathers favorite animals! I only had a chance to meet him once, he left an indelible mark. Thank you Lincoln Park staff for all you do.

My sympathy to all the caregivers of Keo, who's lives he touched so deeply These things are always difficult, never easy. Many grateful blessings for all you who enriched Keo's life.

A windy,
A rainy,
A walk-in,
A Keo,

Thank you all for taking such wonderful care of Keo for all these years. My heartfelt condolences to all of you.

Precious Keo was a treasured part of the LPZ family, and we will miss him dearly. He was a joy to know, and we are grateful for a lifetime of wonderful memories to cherish. Our thoughts are with all who cared for him with such compassion and love, and he shall remain forever in our hearts.

RIP Keo! May the fond memories of Keo help those who knew him heal quickly.

Our thoughts are with all the staff.
The Chimp Eden Staff
South Africa

Sending my deepest condolences. Thank you for caring for the animals. and for all your good care and loving companionship with Keo.

It is never easy losing a furry family member. I can only imagine your sadness, but I am happy to see he is being remembered in his best light and for the great Chimpanzee he was.

Dearest most precious and adorable Keo,
You have brought me great joy. Visiting you my dear friend was always a special treat. You touched my heart each and every time I had the pleasure of seeing you. You had a great presence and were truly a wonderful guy. I will miss you so very much.

Needless to say, I know you appreciated the loving care you received each and every day from the best, most wonderful, and incredibly devoted zookeepers and staff at RCAA.

My heartfelt sympathy to Keo's wonderful and so very dedicated caregivers.


I worked for the Park District for over thirty years and was in the zoo often and worked in the old monkey house where Keo lived. He was quit the character everyone loved him because he had so much energy and was very smart too.

I remember how he loved to swing around and sing and also punch the walls like he was training as a boxer.

Also you had to watch out if his mouth was closed and he had this kind of smile on his face, that meant he had a mouth full of water and would spray you with it and then run around and laugh.

I'm sorry that he's gone because he was a very unique character, I was just talking about him last week and naturally I was laughing while I was telling my friend about him.

RIP Keo!

Just wanted to comment on the passing of Keo. He was one of my husbands favorite animals at the zoo and always managed to take some time to go see him as often as possible. He was left with lots of good memories of his years at the zoo and enjoyed that job everyday that he was there. I have his honorary employee certificate along with some of the pictures from the zoo on my dining room wall. Hope everyone there is doing fine

I don't think I will ever meet another being on this planet who loved to play "tag" or look at feet more than Keo, and I consider myself lucky to have gotten to know him when I was a research intern at the Lincoln Park Zoo. I will miss Keo and my heart goes out to all the keepers and staff.

I was just 10 years old when Keo arrived at the zoo. My mom and dad would take me to see him many times over the years. Keo was a truly amazing animal. As a child I was so amazed how human-like his eyes were. He certainly lived a wonderful life and touched so many. RIP Keo...see you one day over the Rainbow Bridge.

I met Keo very briefly during a tour of the Lester E. Fisher Center and the experience of connecting eye contact with him was unlike any other connection I've had with other animals. I knew he was special and I can only imagine the sadness that is being felt by those who had a deeper relationship with Keo. I'm sorry for the loss to those that were closer to him, glad I was able to meet him if only for a few minutes.

I was very sad to hear about this today...
Keo was the first ape I ever had any interaction with (even if it was through the thick glass of the RCAA building). I will always remember the first time I saw Keo, he looked me up and down, and left only to come back with a head of lettuce. Looking me up and down again he then walked a few feet away and sat down with his back to me. As he peeled away layers of the lettuce he kept looking back at me. I don't know what Keo was thinking... he could have been inviting me to share a head of lettuce with him or perhaps he was saying haha I have some lettuce and you don't. I'll never know, but I know how it made me feel. I knew that this animal was cognizant. There was a personality, a heart and soul to this chimpanzee. And that is something I will never forget. No matter what people say about a certain species, no matter how low or insignificant they seem to human society I know that there is more than meets the eye. Keo taught me that :) Thank you Keo!

My sincere condolences ! As hard as it may seem, try to remember all of the fun times and laughter together. And know that you guys do a great job with all of the animals !!

Thinking of all the keepers and staff who cared for him everyday (and Vicky and Kibali, too).... he will be greatly missed....

I will always cherish the moments I was able to share with him and all the joy he brought to so many. A priviledge... A joy... a wonderful gift from God....


I'm so sorry for your loss. :(

Sending You my heartfelt Sympathy and Condolences,.
Having to make that decision to end an animals' life is very difficult . I truly feel for you,..
Take comfort in knowing that you all gave Keo a wonderful life in captivity,
He was loved,revered,respected and he shall be sorely missed,
Rita Stevenson
Animal Rights Advocate for Chimpanzees

Farewell, Keo. You were so amazing and full of personality. Everyone who chooses to work with non-human apes knows how similar they are to us. Keo really made you feel it. Thanks to the keepers for giving him such a long, high quality life. Thanks to Keo for bringing to so many people, touching our hearts, and for making us all want to be work harder towards conservation and the well-being of chimpanzees. It was a real gift getting to know you.

As a former docent, I remember Keo. My sympathies go to all who cared for him.

Keo, you brought so much pleasure to those who knew and loved you for so many years. How privileged we all were to have known you.

So sorry for your loss. It's so hard losing a friend. Cherish your memories of Keo.

I have known Keo since 1967 and was his keeper from 1978 till 1988 when he was in his prime. Keo was a tough, intelligent and handsome chimp. I will always remember the specific sound of his drum beat that was such a part of his display. RIP old friend. Give my love to Patsy and Sinbad.

I had the great pleasure of spending time with Keo as a research volunteer, and he was amazing. My condolences to all who knew and loved him.

Ias an adult that is one of the hardest decisions to make. My thoughts are with the care givers.

RIP sweet Keo. I hoped where you are now there are lots of bare feet for you to look at. See you on the other side, handsome guy. I will miss you forever.

To our beloved Keo who gave us so much happiness and love in our lives. We were so blessed to know you and to enjoy our many visits together. Your loss is felt by all that knew you.

Not completely sure how I feel about intelligent creatures being kept in captivity but it appears he was well taken care of and had a much longer life than he would have in the wild, but was it fuller and happier? Glad that's not my call.

Post new comment

The content of this field is kept private and will not be shown publicly.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Allowed HTML tags: <a> <em> <strong> <cite> <code> <ul> <ol> <li> <dl> <dt> <dd> <img> <div>
  • Lines and paragraphs break automatically.
  • You may insert videos with [video:URL]

More information about formatting options

By submitting this form, you accept the Mollom privacy policy.