The Gorilla Foundation ( has pioneered Interspecies Communication (IC) with gorillas for over 4 decades.  Through an integrated process of research and gorilla care, we have worked with and cared for 3 western lowland gorillas: Koko, Michael and Ndume. 

The focus has been on using sign language as a primary tool, as it is the most natural way for humans and gorillas to communicate, given their intrinsic gestural capabilities.  We have used IC to understand the great ape mind, and applied it to both improving their care in captivity and increasing empathy worldwide to spare them from extinction.  

However, there is still a long way to go — captive gorillas in zoos are still not permitted to learn or use sign language with their caregivers or the public, and not enough people in Africa are aware of the profound implications of interspecies communication with great apes.  The Gorilla Foundation aims to close this gap and bring interspecies communication to scale.


Can We Really “Talk” with the Animals?

Humans have wanted to talk with the animals for centuries. From early mythology to the fictional children’s books featuring Doctor Doolittle in the early 20th century, either humans or animals (or both) have been imagined with “special powers” to understand one another’s language.

However, it wasn’t until the mid 20th century that someone (Allen and Beatrix Gardner in 1967) had the brilliant idea of trying to teach “sign language” to a chimpanzee (Washoe). This made sense as chimpanzees (and other great apes) are the closest genetic species to humans, they use gestural communication with each other, and earlier attempts to get them to “speak” (such as Viki, a chimpanzee) failed due to inherent physiological limitations.

The success of PROJECT WASHOE prompted Dr. Francine “Penny” Patterson to attempt a similar study with gorillas, in 1972, which became known as PROJECT KOKO, and later evolved into The Gorilla Foundation.


Why “talk” with the animals?

There are many reasons to attempt to communicate with other species — especially our fellow great apes — and benefits for all concerned:

1) We get to learn more about their thoughts and feelings, and because of our similarities, this helps us to understand more about our own cognitive development as a species.

2) It enables us to take better care of them in captivity (zoos and sanctuaries), as they can tell us what they want and need, and we can optimize what we give them to maximize their comfort or joy

3) It enriches both their lives and ours in captivity, enabling them to develop richer, more interactive relationships with their caregivers. This also enriches the lives of their caregivers, converting what could be come a routine job into an evolving learning experience and in some cases a friendship.

4) It increases interspecies empathy, and can thus have a major impact on conservation. Imagine zoo visitors not only being able to “watch” gorillas in their enclosures, but also being able to understand their conversations, with each other, their caregivers, or even the visitors themselves (if moderated by caregiver hosts).

5) With increased empathy for other species comes the strong inclination to save them from unnecessary (man-made) extinction in the wild, and increased responsibility for our shared environment, and by protecting their environments we also protect our own.


Project KOKO

The Gorilla Foundation is best known for Project Koko, the first and only interspecies communication study ever performed with gorillas. It is also the longest running interspecies communication study in history (46 years). It involved 1 female and 2 male Western Lowland Gorillas: Koko, Michael and Ndume, and began in 1972, when Koko was one year old.


Koko was born in the San Francisco Zoo in 1971 and spent the first six months of her life in the nursery of the children’s zoo behind a glass window where the public could see her and where Penny Patterson, then a Stanford graduate student, met her. From age six months to one year Koko was critically ill and moved to a trailer on zoo property. Penny began working with Koko when she recovered her health, and requested permission from the zoo to continue working with her as part of her Ph.D. research in psychology at Stanford University. The zoo agreed as long as Penny agreed to make at least a “4-year” commitment.

In 1974 Koko and her trailer were moved to Stanford University where Penny and Dr. Ron Cohn continued to work with her, and they have been together ever since. Michael, a male gorilla, joined Koko in 1976, and in 1979 the whole group moved to Woodside, CA where Ndume, a second male gorilla joined the group in 1991.

In the years since 1971, Penny (Dr. Patterson) has spent her life caring for Koko and the two male gorillas (Michael and Ndume) — with a very dedicated rotating team — and has established highly empathic relationships with them that may be difficult to replicate by others due to the commitment required. A successful program such as this requires using language during daily documented interactions, as well as the ability to “listen” to the gorillas and discern their meanings. Few people have the patience, stamina, and sensitivity to achieve this.

With Penny’s help, Koko has learned to use over 1,000 signs and seems to understand approximately 2,000 spoken English words. Further, Koko understood these signs sufficiently well to adapt them or combine them to express new meanings that she wants to convey. Importantly, Koko began learning to sign from Penny in just a few short weeks. Penny believes this is because signing is “wired in” to the great apes (over a hundred natural, untaught, gestures have been observed in zoos around the world. This bodes well for any gorilla in captivity who could benefit from a closer relationship with his/her caregiver, which is made possible through two-way communication.

Sadly, Koko passed away in her sleep on June 19, 2018, at the age of 46 (2 weeks before her 47th birthday on July 4th). She gave the world a whole new paradigm for gorillas (from King Kong to Koko’s Kitten), volumes of multimedia data on interspecies communication and care to build upon, and inspired millions of people around the world to care about their fellow great apes, and our shared environment. Her legacy will live on through all the other gorillas and children she has affected — and through the continued work of The Gorilla Foundation.



Gorilla Michael, who grew up with Koko from age 3, was a “bushmeat orphan” and apparently witnessed his mother killed by poachers before being rescued and sent to a European zoo. He too learned hundreds of signs of signs (over 500 by the time he was an adult), and developed other communication-related skills, such as painting beautiful representational and abstract works of art.

Michael passed away in 2000 at the age of 27, from Cardiomyopathy (an enlarging of the heart muscle) a disease which is fairly common in captive male gorillas, and is possibly stress-related.

The fact that Michael was able to learn sign language as easily as Koko points to an important observation that is supported by other research as well as our own: Koko is not unique. There is nothing special about Koko or Michael. They were selected from two completely different environments not because they had a predisposition for communication, but because they both needed a loving home. Sign language appears to be a natural form of communication for gorillas (they have been observed using over a hundred natural (untaught by us) gestures in captivity), and so why not teach them a “common” form of sign language so that we can understand each other better? And the fact that Michael was able to remember his mother being killed by poachers (possibly the only first-hand account of the “bushmeat” trade by a survivor, suggests that orphan gorillas living in sanctuaries might find a shared sign language a useful therapy for dealing with PTSD.



Finally, Ndume came to live with Koko and Michael in 1991 at age 10, from the Cincinnati Zoo, and lived at the Gorilla Foundation’s Woodside Sanctuary for 27 years, as Koko’s close companion (she selected him via something like “video dating”). Ndume came with some of his own natural gestures, and learned more from both Koko and caregivers. However, at the request of the zoo who “lent” Ndume to us, he was never formally taught sign language. After Koko passed away, the zoo decided to exercise their right (in our agreement) of returning him to the zoo. At the time of this writing, he has been there for only a few days, accompanied by two of our caregivers, and we are all hoping he will adapt to his new (and very different for him) environment. However, it is a stressful time for everyone, as while gorillas are the largest and strongest great ape species, they are also the most emotionally fragile.



The following 3 video clips provide highlights of interspecies communication recorded with gorillas Koko, Michael and Ndume. Note, that over 2000 hours of videos have been collected during Project Koko, but only a fraction have been studied sufficiently to share with the public. There is much to do; and one of our Top Initiatives, the Koko Archive, is intended to complete the “Koko Digital Archive” with the help of both the general public and interested researchers.

Video Introduction to project Koko

Collectively, our experience with Koko, Michael and Ndume — who were essentially randomly selected to be part of Project Koko — indicate that Koko is not unique, and that all (or at least most) gorillas have the capacity to engage and benefit from interspecies communication.

Other Great Ape Interspecies Communication Projects

All 4 of the (nonhuman) great ape species have participated in interspecies communication studies — gorillas, chimps, bonobos and orangutans.  However, Project Koko is the only one involving gorillas, and there are only one or two noteworthy projects involving each of the other great ape species.  Why are there so few such projects, and where are the new ones on the horizon?  The answer is probably related to the apparent time and resource commitment required to create and sustain a successful great ape IC program — and the need to provide the participating great apes with optimal care and continuity throughout their lives.  And once a successful project has been demonstrated, there may be a feeling that it’s been “done” and no further work is needed. 

However, just the opposite is true:  Because of the decades of progress achieved thus far, IC with great apes is poised at the beginning of what could become exponential growth and rewards.   By utilizing the results, lessons and data that the pioneers of IC have established, and adding some of the technologies that weren’t available at the outset of these projects,  huge benefits for captive and free-living great apes can be realized.  The benefits for humans are just as great, including a closer connection to Nature, a better understanding of our role as stewards of the planet, and a more empathetic world, as we learn to appreciated how much other species are like us emotionally.


Project Washoe was the first study showing that great apes could learn to communicate using American Sign Language.  Chimpanzee Washoe learned approximately 350 ASL signs, and also taught some of these signs to her son Loulis.

Washoe was originally raised and taught by the Gardners (Allen and Beatrix) and later by the Fouts (Professor Roger and Deborah) at the University of Oklahoma, and later Central Washington University.

Washoe passed away in 2009 and the rest of the troop was moved to Canada.

Project KANZI (BonoboS)

Kanzi is a male bonobo, born in 1980, who has been featured in several studies on great ape language with primatologist Dr. Sue Savage-Rumbaugh, and has exhibited advanced linguistic aptitude using a keyboard with Lexigrams (rather than sign language).

According to Savage-Rumbaugh, Kanzi also learned some ASL signs by watching Koko the gorilla on video.  And like Koko, Kanzi also learned to comprehend spoken English.

Project CHANTEK (Orangutan)

Chantek was taught over 150 words of American Sign Language by his mentor, Dr. Lyn Miles, as well as anthropologist Ann Southcombe (who also worked with gorilla Michael in Project Koko).

Like Koko, Chantek learned to understand many words of spoken English, and created art, necklaces (made of beads) and music.

Chantek passed away in 2017 at age 39.  You can learn more about Chantek and Project Chantek, watch the documentary:  The Ape who Went to College.

Non-Gestural Forms of Interspecies Communication

While sign language is the most obvious form of communication to attempt with another species who looks like us, gestures like us, but doesn’t have the vocal capacity of humans, other useful forms of two-communication have emerged in the process, including:

Symbols: In Project Kanzi a Lexagram is used to allow bonobos to point to pre-defined abstract symbols within a table of symbols.  The human can either point to the symbols too, or communicate in Spoken English.


Language Cards:   As Koko was read to by caregivers throughout her she learned to recognize many words and sentences in writing.  Thus, we experimented with placing simple phrases and sentences on 3×5 cards stored in a bin.  Koko would often take out the most appropriate card to indicate her meaning and place it on the floor in front of the caregiver.  For example:  “Time Eat Now” . or . “Get Ron Please.”

Visual Art:  Gorillas Koko and Michael began painting at an early age, and by the time they were adults they were capable of producing sophisticated paintings that represented either physical objects (eg, flowers or animals) or abstract feelings (eg, love or anger).


Charts:Koko learned to use a “bar chart” to indicate her level of physical or emotional pain or pleasure on a scale from 1 to 10.

Spoken English (Comprehension): The most unexpected aspect of most great ape communication studies is how much “spoken English” the great apes are able to comprehend (not produce).  This was especially true of Koko and Michael, as their caregivers made a habit of speaking and signing at the same time, so that the gorillas eventually learned to understand spoken English even without someone signing.  For example, Koko learned over 1000 words of American Sign Language, but in the process learned over 2000 words of spoken English.



Interspecies Communication with Non-Ape Species

It may be obvious why the most productive interspecies communication studies have been with great apes — as humans are “great apes” too, and all “walk, talk and look” very similar. But what was’t so obvious at the time these IC projects were initiated is that great apes have been using their own “sign language” long before we attempted to teach them ours (eg, ASL). This makes the process of learning our sign language relatively easy for them, with the determining factor being the patience of the teacher, and degree to which the subject and teacher actually liked one another. 

Nevertheless, there have been successful interspecies studies with non-great-ape species, such as:

Parrots (e.g., Project ALEX:  Spoken English sudies by Dr. Irene Pepperberg)

Elephants (e.g., Infrasonic Communication studies by Dr. Caitlin O’Connell)

Dolphins (e.g., Dianna Reiss, Hunter College)

and who knows which other species can break the “interspecies communication barrier” especially with the help of specially designed AI algorithms to augment natural language recognition.  

But even if there’s a limit to which species we can learn to communicate with, there is still much to learn about how other species communicate with each other (intra-species communication), and as we begin to learn their “language,” the possibilities for two-way communication increases.  Moreover, as we learn more about how other species communicate,  we can also learn to give them more control over their environment in captive (or human-dominated) settings, by offering them choices (see, for example, Dianna Reiss‘ work with dolphins).

The Science of interspecies Communication

The original scientific goal of Project Koko was to see if it was possible to teach gorillas sign language and, if so, how much we could learn about their cognitive abilities through direct communication. This goal, which to a large extent has been achieved, has evolved to include other forms of communication, and the focus has shifted from pure scientific inquiry to producing benefits for great ape welfare, education, and conservation, using scientifically validated methods.

Nevertheless, the scientific approach used to establish that Koko and Michael learned to communicate spontaneously, creatively, and with full comprehension, is instructive for other researchers who would like to either verify or extend the conclusions and applications of Project Koko.

As the communication vehicle used in Project Koko is American Sign Language (ASL) — augmented by the gorillas’ own “natural” (untaught) gestures and new signs invented by them to compensate for gaps in their education — the focus is primarily on:  a) the acquisition of new signs, and b) the use of signs to form grammatically meaningful and consistent phrases or sentences.

The above 2 charts describe Koko’s acquisition of new signs during the first 10 years of the project (when Koko was between age 1 and 11).  Note that Koko’s incremental rate of sign acquisition is very similar to that of human children, in that it peaks between ages 2-4; and her cumulative sign acquisition begins to level off at around age 10.  Koko’s total vocabulary continued to grow throughout her adult years, as she invented new signs (as necessary to communicate); however, she eventually settled on  a small subset of her total vocabulary for everyday communication (between 50-100 of her “favorite” signs).

Scientific Papers and Data Generated by Project Koko

Dozens of scientific papers and thousands of pages of scientific notes based on direct observation and interaction have been generated over the years by Project Koko.  Because the scientific papers have largely been overshadowed by the popular media (for example, Koko’s meetings with celebrities, her first (experimental) internet web chat, and various documentaries), we present 2 representative downloadable papers below that provide a good description of the methods used, and the scientific rigor applied.  We also show one example of the type of “coding” used in our research database to indicate the linguistic characteristics of interspecies communication, for subsequent analysis.

Tools for Interspecies Communication

Following are examples of some of the tools created by The Gorilla Foundation to facilitate and/or inspire communication with (captive) gorillas living in sanctuaries or zoos.  From books to videos to multimedia presentations to a new interactive phone app.  The newest and most important tool, the Koko App is specifically designed to help others develop a basic level of communication with gorillas (or anyone who uses sign language). 


Click the book to buy


Click the book to download


Donate to get the book.




Click the DVD to buy
Click the DVD to buy
Koko has her own DVD library

Multimedia Presentations

School Presentations (Grades 1-12)

Scientific Presentation (Sample)

The “Koko App”


  1) Learn to sign from Koko (video closeups)

  2) Teach more gorillas to sign (all gorillas are Kokos)

  3) Learn “their” natural signs

  4) Improve gorilla care in captivity

  5) Save them from extinction in the wild

  6) Increase interspecies empathy

  7) Learn from biodiversity

  8) Inspire “kids” to be conservationists

  9) Motivate “Interactive Sanctuaries” (see below)

10) Facilitate an “Interspecies Internet” (see below)

11) Crowd-source Project Koko video research

The Future of Interspecies Communication

If interspecies communication is used wisely, it can become ubiquitous, and lead to greater understanding and empathy for our fellow sentient beings.  The following two scenarios illustrate the vision that The Gorilla Foundation and several other organizations are working towards, with the help of like-minded donors, sponsors and partners.

Interactive Sanctuaries

Gorillas are not suited for living in Zoos with on-site visitation by strangers.  The Silverback, who is responsible for protecting his entire family group is unable to do so in zoos, and this creates great stress for him and others.  In fact, a large percentage of adult male gorillas (Silverbacks) die of cardiomyopathy, and stress can cause cardiomyopathy. 

There is a better solution for both them and us:  Convert the great ape exhibits in zoos (for starters) to internal sanctuaries with high-definition video screens for visitors to watch the gorillas live in privacy and/or interacting (which preferably includes communicating) with their caregivers.  In summary:

  • Because Gorillas and other great apes are “stressed” by visitors (males die of cardiomyopathy)
  • Convert great ape exhibits to “sanctuaries”
  • Provide HD real-time video screens/links to the public
  • Feature interactive sessions between caregivers & (selected) subscribers
  • Enable interspecies communication between gorillas, caregivers and selective subscribers
  • Use interspecies communication to study gorillas’ natural gestural systems too

The Interspecies Internet

There has been a growing interest — spawned by a small group of visionary thinkers like Peter Gabriel (musician), Vint Cerf (Internet Evangelist for Google), Neil Gershenfeld (MIT Professor and FabLab Founder) interacting with a small group of interspecies communication specialists like Diana Reese ( ), Sue Savage Rumbaugh, Penny Patterson and others — in extending internet access to some of the most communicative nonhuman animal species (eg, great apes, dolphins, parrots, elephants, et. al). 

Theoretically, this would make it possible for both same-species communication across large distances (imagine a gorilla who is not able to live with a mate communicating with a gorilla family lacking a silverback), as well interspecies communication (eg, humans and great apes, humans and dolphins, great apes and dolphins, chimps and gorillas, etc.)



• Other species communicating with each other and us via the internet

• Isolated animals make “friends”

• Special devices for each species

• Research

• Enrichment

• Conservation

• Entertainment



• Not all animals want to interact with “devices”

• Research can be painstaking (not entertaining)

• Shared language required for humans to buy in



The Koko App could be the catalyst that enables both Interspecies Sanctuaries and the Interspecies Internet to be a reality.  When humans expect captive great apes to sign back to them when they sign “you’re a good gorilla,” that’s when there will be sufficient demand to bring them both to fruition.