Michael Memorial
In loving memory of Michael, the silverback gorilla.
The stories and emotions he communicated to us through sig and art inspired us all.
Best friend of Koko, Dr. Patterson & Dr. Cohn who raised him.
His magnificence changed our view of the world.
Michael's memory and message will live on.

What was the Cause of Michael's Death?

On June 29, 2000, The Gorilla Foundation received the pathologist's report from Dr. J. Werner of the University of California at Davis Veterinary Hospital, confirming that the cause of Michael's unexpected death on April 19, 2000 was heart failure due to fibrosing cardiomyopathy. Michael was the male gorilla who was raised with Koko and communicated using over 500 modified American Sign Language gestures.

Fibrosing cardiomyopathy is one of two major cardiovascular diseases found in gorillas. (This disease is also found in humans.) The other disease is aortic dissection. These diseases occur mostly in males and are seen more frequently in older gorillas. Cardiovascular disease accounts for 41% of deaths in adult gorillas, and 70% of deaths in males over 30 years old.

As was the case with Michael, there is usually no warning of the problem, and it remains undetected until it manifests itself in sudden death without any outward signs of disease. Much study still needs to be done to determine what causes this condition in gorillas, as well as what can be done to prevent it.

Many measurements we use in humans to monitor heart conditions, such as monitoring blood pressure, are not easily used on gorillas. There are two problems with this method of monitoring. Researchers do not know what a "normal" range would be for gorillas. The only measurements taken thus far have been on anesthetized gorillas, and these levels are higher than what is normal for a human. The second problem is gorillas can have fibrosing cardiomyopathy, yet not exhibit hypertension (high blood pressure), so regular monitoring will not necessarily indicate the disease. Michael was one of these individuals who exhibited no signs of hypertension.

Other methods of monitoring are currently being studied to try to detect fibrosing cardiomyopathy while there is still time to treat the afflicted gorilla. We can only hope the information doctors have collected from Michael's death will lead to ways of diagnosing and treating other gorillas who may have the same disease, but do not show any evidence of it.

How Did Koko and Ndume Mourn for Michael?

Koko was extremely upset by Michael's death. She spent 24 years with Mike, and he was her companion since she was five years old. In the weeks following Mike's death, both Koko and Ndume uttered frequent, mournful cries, particularly at night. Gorillas often vocalize this type of cry when they are unwillingly separated from each other. During this time period, Koko indicated with sign language that she wanted a light left on at night when she went to bed. Both Koko and Ndume often stared into the distance without focusing, apparently seeing nothing. For months following Mike's death, Koko would sit with her chin on her chest and her lower lip dropped down, a recognizably sad expression.

Both Koko and Ndume were reluctant to spend time alone after Mike's death, so their caregivers stayed with them much more than usual. Koko uttered her sad cries nightly for long periods after bedtime. She was rarely happy and uncharacteristically didn't "purr" when she was given food or was in the presence of someone with whom she had bonded strongly, such as Dr. Penny Patterson, Dr. Ron Cohn or one of her favorite caregivers. In this, the last week of July, Koko's mood has begun to lift a little, though she is still not back to her old self.

In the evening of the day Mike died, Koko searched through his rooms looking for him, and she signed to Ron, "Sip Mike Mike Lip, " signing the gesture for "Mike" once with each hand. When Ron said "Mike is gone," Koko returned to her own room and started once again to utter plaintive cries. The following morning, when Ron asked Koko what she wanted, Koko replied," Sip Mike Lip." In late July, she signed once again, "Sip Mike Lip." Koko does not make random signs, and by signing this on three separate occasions, she is trying to tell us something. Dr. Patterson believes that Koko may be commenting on the CPR she saw performed on Mike in an attempt to revive him.

The next day, Penny and Ron sat with Koko. Penny cried as she tried to explain what had happened. Koko signed to her, "Cry no." Penny interpreted this as Koko attempting to console her. Penny opened both of Mike's rooms, and Koko quickly went in. She looked through his blankets and tubs and then peered through the window to the yard, as if hoping to find him there. She spent several long moments in silence as she sat among Mike's things.

Did Ndume Assume the Role of Koko's "Silverback?"

Slowly, Koko's mood began to lift as she adjusted to life without Mike. Her relationship with Ndume changed too, as he began to assume the role of the silverback alpha male. Interestingly, as Ndume began to take on more of Mike's behaviors, Koko began to take on more of Ndume's, perhaps an outward sign of identifying with Ndume more than she had in the past. These behaviors included running while chest slapping and clapping (a behavior typical of Ndume, but never before displayed by Koko). She also began throwing things, also an Ndume trait. Koko then became willing to be in closer proximity to Ndume than she had ever been  before. In fact, she engineered these closer interactions, going into a smaller yard to encourage him to come in and interact. When caregivers interacted with Ndume, she would interfere with their interaction much more than before, signing Ndume's name and seeking to focus his attention on her rather than on the caregiver. Koko and Ndume began to be seen running by each other in the yard, back and forth, getting closer each time and exchanging what can only be described as a "high-five." Koko also approached Ndume much closer than before while he was nesting; he stopped getting up and moving as he used to when Michael was still alive. 

Press Relese on Michael's Death, Aug. 2, 2000

The Gorilla Foundation/koko.org, home of the world renowned gorilla sign language project, regrets to announce the death of our dear friend, Michael the gorilla.

Michael, age 27, was born in Cameroon, West Africa, and came to the Foundation in 1976. He had been cared for, taught by, and teacher to Dr. Francine "Penny" Patterson, Dr. Ronald H. Cohn and the staff of the Foundation since he was three and a half years old.

Michael is one of only two gorillas in the world to have learned a human language. He mastered well over 500 signs in American Sign Language and understood spoken English as well. In addition to his language abilities, Michael was a talented and prolific painter and a lover of classical music.

Michael is survived by his lifelong friend, Koko and his companion Ndume. He was deeply loved by The Gorilla Foundation's staff, members and friends throughout the world. The Foundation is especially sensitive to the impact that Michael's death may have on the many, many children who have expressed their love with letters and drawings sent to the gorillas over the years.

Dr. Patterson said of Michael's passing, "We are deeply saddened by the loss of our dear friend Michael. He has been an inspiration to us all. He had a great facility with gestural communication and was a talented artist. His work has been displayed in galleries around the country. He was our group's silverback and we will miss his strong presence a great deal."

At 10:45 a.m. PDT gorilla caregiver Megan Dunn saw Michael collapse onto his back in his outdoor play area. She noted that he had labored breathing and was non-responsive to her calls. Dr. Patterson was notified immediately. She had her staff contact 911 and rushed to Michael's aid.

Despite the valiant efforts of Dr. Patterson and Foundation staff, Michael passed away at his home in Woodside.

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The Gorilla Foundation / Koko.org
1733 Woodside Rd., Suite 330
Redwood City, CA, 94061
1-800-ME-GO-APE (634-6273)

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Our mission is to learn about gorillas by communicating with them, and apply our knowledge to advance great ape conservation, education, care and empathy.

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