Great apes and their attitude towards other animals

Last Sunday I gave a lecture in Den Bosch on a course day about cat behaviour, organized by the Kattengedragsadviesbureau (AdvisoryBureau on CatBehaviour) of Marcellina Stolting (in cooperation with behavioural biologist Els Peeters of the University of Antwerp, Belgium). My lecture had as its title Great apes and cats and presented what is known about the way in which chimpanzees, bonobos, gorillas and orangutans relate to cats and other animals. The emphasis of my lecture was on the great apes who were used in language research, the scientific research in which it was tried to teach these great apes some form of human language.

Language research with great apes

When Darwin published his evolution theory in the 19th century and, in doing so, argued for a biological kinship between humans and other apes, scientists became very interested to study the differences and similarities between humans and other great apes. One of these issues concerned the question whether nonhuman great apes could learn some form of human language. At the beginning of the 20th century, scientists first started experiments in which they tried to teach great apes a spoken language. This was not successful, however. The best result came from the chimpanzee Viki, who in the 1950s, after 6 years of intensive training, learned to pronounce, with great difficulty, the words “papa, mama, cup” and “up.” Often she spoke them hoarse and almost inaudible and Viki also often used the words for the wrong referents.

In the 1960s, after extensive research had demonstrated that human sign language is just as complex as, and equal to human spoken language, scientists tried to teach language to apes by using sign language. They succeeded in teaching signs to apes and the apes used them in their communication with humans.

The chimpanzee Washoe, the first great ape to learn signs

The first ape who was taught signs was in 1966 the chimpanzee Washoe, who eventually learned about 150 signs that referred to all kinds of objects and actions. The success with Washoe led to other projects with signing apes: in 1972 a project started with the gorilla Koko, in 1973 another project with a chimpansee, Nim Chimpsky, and in 1978 with the orangutan Chantek. Besides this, scientists also taught chimpanzees and bonobos to use lexigrams to communicate: geometric symbols that refer to certain objects and actions. The famous bonobo Kanzi has, from the beginning of the 1980s, learned to use several hundred lexigrams.

Characteristic of most of these language projects was that the researchers tried to make these often young apes grow up in an environment that mimicked as much as possible the environment in which a human child grows up, considering that in such an environment the apes would have the best chance of picking up human language. For this reason the apes often grew up in a human family, they were dressed in clothes, learned how to brush their teeth and use a toilet, and they learned discipline and helped in keeping the house clean, by being asked things like helping with the dishes. Of course there was also lots of play with the apes and they were given dolls and other toys to play with. In the 1970s the signing apes were also regularly taken out in a car to walk outside in nature or to visit McDonalds and other places for some snacks.

In the human environment in which these apes grew up, they also came into contact with cats, dogs and other animals. In many cases these were the pets of the people in which house the apes lived. In the literature about these language projects with great apes one can find interesting information about how these apes related to other animals.

Koko and All Ball

Famous is the story about the signing gorilla Koko and her kitten All Ball. This kitten was a Manx cat, which Koko had chosen herself from a litter of abandoned kittens. Because the kitten had no tail, Koko named her, according to the researcher Penny Patterson, ALL BALL. Koko was delighted with her kitten, she petted him, played with him and did so carefully. Koko described her kitten as SOFT GOOD CAT. After several months All Ball died after a car accident and when Penny told Koko that her kitten was dead, Koko would have signed CRY, SAD and FROWN, as an expression of her grief. Watch a short  film about Koko and All Ball below.

I have to mention here, though, that not all claims that have been done by Penny Patterson about Koko’s signing are correct. In 1995 I paid a working visit to the Gorilla Foundation in Woodside, California, where Koko lives since the end of the 1970s. There I was given access to the Koko diaries in which all sign use by Koko was written down from the beginning of Project Koko. I discovered that Patterson had sadly been very selective in what she published about Koko’s signing. Sign utterances that seemed meaningful or languagelike were published, but all other, less meaningful utterances were not. Thus, I found in the unedited, unpublished data that Koko was sometimes bothered daily to make signs such as CRY, SAD and SMILE, often by presenting her with pictures and images. Koko then signed CRY CRY to a picture of a smiling man, BIRD. SAD CRY SAD CRY to a picture of a snake, and SAD CRY DEVIL to a picture of a horse. One should therefore not take the published sign utterances by Koko too seriously, given that the published data on her sign use are not reliable.

After All Ball, Koko was given a few other cats, which she related to lovingly, and which she called LIPSTICK and SMOKE, according to Patterson. Koko was also very interested in a blue jay and in several tree frogs.

The chimpanzee Nim Chimpsky

The chimpanzee Nim was also very delighted by cats. He loved holding a cat and playing with it. Regularly, a cat was brought to the special classroom in which Nim was taught signs. He then became very excited and signed CAT, CAT HUG, CAT ME. If he was then allowed to hold the cat, Nim would get a broad grin of pleasure. The humans then had to take care that Nim wouldn’t pull too hard on the cat’s tail or leg, because Nim often didn’t know his own force. This is true for all the great apes in language research: only under supervision of humans were they allowed to have contact with cats and dogs.

In his book Nim Herbert Terrace describes a fun occasion when the human Susan wanted to feed the cat some yoghurt. Nim enjoyed pretending with humans that he was feeding his dolls. He seemed to understand that that couldn’t hurt, because the dolls wouldn’t eat the food he offered, in which he usually was interested himself. When Susan wanted to feed a spoon of yoghurt to a cat, Nim took the spoon out of her hand and fed the cat himself. However, to his amazement, the cat ate the yoghurt! When Nim was then asked to feed the cat again, he offered the cat an empty spoon and then quickly took himself some yoghurt. Below you can watch a short film about Nim and cats, a short clip from the documentary movie Project Nim, which is now playing in cinemas in the US and the UK.

Nim also liked to play with dogs, whom he would then chase. He also used the sign PLAY to iniate play with cats and dogs and would even use this sign with horses.

The chimpanzee Lucy

Another signing chimpanzee, Lucy, who grew up in the house of Jane and Maurice Temerlin, was given a kitten in order to “develop her maternal instinct.” Lucy turned out to be an overprotective ‘mother’ who would carry her kitten everywhere, even when the cat itself didn’t like this. Roger Fouts describes in his book Next of kin that the cat always tried to escape when Lucy came to her, sadly without success, as Lucy always knew how to catch him. Soon the cat would fall down into a limp heap whenever Lucy came into the room, knowing that Lucy wouldn’t take notice of the cat’s own wishes. Once the cat tried to get away from Lucy by holding onto a wire cage. Lucy, however, pulled him off from there and in doing so damaged the cat’s pads on its paws. The humans took the cat away from Lucy and made it clear to Lucy that she had hurt the cat. When she eventually was given the cat again, Lucy would have taken the cat in her arms, and signed HURT HURT while pointing to the cat’s paws.

Sue Savage-Rumbaugh and the bonobo Kanzi using the lexigram board

The bonobo Kanzi

Kanzi and the other bonobos who were taught to use lexigrams to communicate by Sue Savage-Rumbaugh, also were big pals with dogs. When Kanzi was still young he would also have used lexigrams like “play” to ask the dogs to play with him. When Kanzi was older he seemed to realize that the dogs didn’t react to his lexigram use, so he then stopped using lexigrams with the dogs.

Tearing dogs apart and killing them

According to the researchers from the language projects the signing apes would also sometimes make insulting remarks about other animals. Lucy would have called a local tomcat that she didn’t like DIRTY CAT and the signing orangutan Chantek called noisy birds BAD BIRDS. Koko too, would have signed DARN BIRD and ROTTEN BIRD to a bird who was giving alarm calls for minutes on end.

Observations have also been made of less friendly behaviour by the apes towards other animals. Viki used to enjoy scaring the neighbours’ cats. Several signing chimpanzees have sometimes attacked cats. A Doberman pinscher who was used as a guard dog, was ripped apart by chimpanzees.

The chimpanzee Bruno also was destined to learn signs. He had been sent before Nim to Terrace in New York at the end of the 1960s as a sort of practice ape for his language project. After about half a year Bruno was sent back to the primate institute in Oklahoma where many of the chimpanzees who would learn signs were born. The director of the institute, Bill Lemmon, however, decided that Bruno should quickly be sent off again, this time to a childless couple, to grow up in their house. Poor Bruno, who was then 14 months old, constantly clung to his new foster mother the first few days and apparently wasn’t happy with the whole situation. A few days later he tore apart two fully grown St. Bernard dogs and a few further days later the cow of a neighbour. The dogs survived, but the cow didn’t. After 3 weeks Bruno was sent back to Oklahoma. It is remarkable, by the way, how the great apes in the language projects have been used and moved about all the time, giving little regard to their own well-being.

Nim too showed a less friendly attitude towards a dog when he was older. Nim had had by then a whole history of hardship and suffering. After the experiment with Terrace ended, Nim had been sent back to Oklahoma, where he was sold in 1982 by Lemmon to the biomedical laboratory LEMSIP in New York state, where he was planned to be used in hepatitis research. The press came out with this story and Terrace begun a campaign together with others to liberate Nim and several other chimpanzees from the laboratory. With lots of pressure from public opinion, this campaign was successful and Nim eventually was brought to the Black Beauty ranch of the American animal protectionist Cleveland Amory. (Bruno also ended up in LEMSIP, where he was injected with hepatitis and eventually died there.) On the ranch Nim was bored and lonely. He then had the habit of breaking out of his cage and go to the ranch’s manager’s house, where he’d raid the refrigerator and would lie down in a bed. Once the miniature poodle of the manager was in the house, who came running to Nim while barking hysterically. Nim then grabbed the dog and banged it against the wall several times, covering the place with blood. Elizabeth Hess, in whose book this incident is described, says that Nim killed the dog because he was frightened.

Other great apes in captivity

Besides the great apes in language research, other apes in captivity have also sometimes become friends with a cat or a dog. Already in the 1930s the gorilla Toto was adopted by the French Augusta Hoyt (Toto had been taken from Africa, her mother had been killed in a hunt). Toto also grew up like a human child in the house of Hoyt, who moved to Cuba with the gorilla. When Toto was 4 or 5 years old, she befriended the kitten Principe, which she carried everywhere. Sadly, when Toto became older and less manageable, she was sold to the Ringling Brothers and Barnum and Bailey Circus.

The orangutan Tonda and the cat TK

Eric's impression of Tonda and TK

Of a more recent date is the friendship between the orangutan Tonda and the cat TK. The female Sumatran orangutan Tondalayo lived with another orangutan in the Zooworld zoo in Panama City, Florida. In 2005 her orang companion died, after which Tonda became depressed. She didn’t eat and wasn’t interested in anything anymore. Tonda was already an elderly orangutan and she was not in such good health. For some reason she was considered too old for a new orangutan companion and she was too frail to be sent off to another location. Her human caretakers didn’t know what to do and feared that she might die of misery. They were inspired, however, by Koko’s story and searched a cat that would be appropriate for Tonda: a playful yet docile one-year-old tabby cat T.K. (short for Tonda’s Kitten). The orang and the cat became friends. They ate together and slept together. They played and cuddled and Tonda always watched her cat carefully, the way a mother watches over her child. Tonda also fed the cat and when it was time for a nap, she would take the cat under her blanket. Tonda get very attached to TK and she became angry when her human caretakers took the cat away. Tonda’s health also improved. In 2009 Tonda died quietly, after which the cat TK was down that his companion was no longer there. Click here for a short film about Tonda and TK.

The chimpanzee Anjana and the cubs

Eric's impression of Anjana and a white tiger cub

The Institute of Greatly Endangered and Rare Species (TIGERS) in Myrtle Beach, South Carolina, is a sanctuary that takes care of all kinds of exotic animals and gives education about them. One of their animals is the female chimpanzee Anjana. She was inseparable of her human caretaker China York. Thus, Anjana was present when York took care of other animals, such as two white tiger cubs who were separated from their mother in 2008 after a hurricane. The then 2-year-old Anjana imitated the care of the tiger cubs and related to the cubs in a very friendly way. Anjana would feed them milk, lay with them and act like a surrogate mother. She cuddled them, played with them, enjoyed holding them and when she heard them cry because they were hungry, she stuck a finger in their mouth like a pacifier. Besides these tiger cubs, Anjana has helped raising leopards, lions and orangutans in the sanctuary. Watch a short film about Anjana and the cubs below.

Killing and eating other animals

Besides these friendships between great apes in captivity and other animals, it is also known that all great apes kill and eat animals that have entered their enclosure. They do so with animals such as squirrels, rats, mice, and birds. This was shown in a recent study by Ross, Holmes and Lonsdorf (2009) in which caretakers from all kinds of zoos and sanctuaries in the US and Canada were asked about their observations. Chimpanzees in particular also used the carcass of the animal in their displays towards their conspecifics. Chimpanzees and bonobos more often showed aggressive behaviour towards animals that had entered their enclosure than gorillas and orangutans. Below you can see a short film about chimpanzees in a zoo in St.Louis, hunting a cat in their enclosure.

It is remarkable that gorillas in captivity also kill and eat vertebrate animals, as this has up to now never been observed in wild gorillas. It has been known, however, that gorillas in captivity eat meat from vertebrate animals that they are offered. The signing gorilla Koko also was offered hamburgers and ate them.

The bonobo Kuni and the starling

In contrast with this is the story about the bonobo Kuni and the starling, which is mentioned in several books by Frans de Waal. Somewhere in the 1990s a starling flew against the windows of the bonobo enclosure in the Twycross Zoo in England. The 7-year-old female bonobo Kuni caught the starling, at which a human caretaker urged her to let the starling go. Kuni took the bird outside and put it on its paws, where it remained immobile. Kuni then threw the starling up a bit, but the bird just fluttered a little. Then Kuni took the starling into one hand and climbed to the top of the highest tree in the outdoor enclosure and when she reached the top Kuni held on to it with her feet and then used both hands to unfold the starlings wings carefully, after which she threw the bird as far away as she could in the direction beyond the moat surrounding the enclosure. Unfortunately, the starling still fell just inside the bonobo enclosure. Kuni then climbed down and protected the starling against a curious juvenile bonobo. At the end of the day the starling was nowhere to be seen: it is assumed that the starling had eventually been able to fly away.

Great apes in the wild and other animals

Chimpanzees and baboons

Jane Goodall calls the interactions between chimpanzees and baboons the most varied and complex of any two other species of animals in the animal kingdom. First of all, play often takes place between especially young chimpanzees and young baboons. The play predominantly exists of chasing each other and hitting each other playfully. Often, however, the play ends up in agression. The chimpanzees and baboons then chase each other while stamping and slapping and the chimpanzees throw rocks and sticks at the baboons. Sometimes actual attacks take place, in which the animals hit each other. Besides play, Goodall has also observed the old baboon Job regularly being groomed by chimpanzees. Also, sometimes the baboons startle a chimpanzee, who then utters a threat-bark, causing the baboon to cower submissively. The chimpanzee would then touch the baboon quietly in reassurance.

Gilka and Goblina

In Gombe Goodall was able to observe the special relationship between the chimpanzee Gilka and the baboon Goblina. When Gilka was 4.5 years old she had at that time no other young chimpanzees to play with and her mother Olly was often fishing for termites for hours on end. Gilka therefore became bored and somewhat lethargic. One day she hears a troop of baboons, goes over to them and Goblina comes over to her (Goblina’s mother had died, but she did have enough baboon playmates). Gilka and Goblina look at each other, put an arm around each other and they start playing. They wrestle and pat each other. They tickle each other with their fingers and give each other playful nibbles with their mouth, all accompanied by soft laughter.

Different from the normal play between chimpanzees and baboons, the play between Gilka and Goblina did not become aggressive, it mostly was gentle and careful. The friendship lasted for a full year. Gilka then travels with her mother Olly to another location and only returns after half a year. Goblina had by then reached adolescence (baboons mature quicker than chimpanzees) and had become less playful and the friendship was not revived. Later two adult chimpanzees would kill Goblina’s first child. Goblina watched the event while calling loudly.

Sexual behaviour between chimpanzees and baboons

Goodall also describes sexual behaviours between the chimpanzees and baboons in Gombe. Already when the chimpanzee Flint was 8 months old, did he show interest in the sexual swellings of the female baboons. Often they would then present themselves to him and allowed him to touch their pink bottoms. Female baboons would also present themselves to other interested young, but also adult male chimpanzees.

Young male baboons also get excited by the genital swellings of adolescent female chimpanzees. They grab their ankles and try to copulate. The baboon Ajax mounted the 9-year-old female chimpanzee Moeza, who wasn’t interested, but let him go, because she was sad that her mother had died. Ajax was unsuccessful in actual copulation, however. When Flint was 7 years old he copulated with the female baboon Apple. He showed her his erection, Apple presented herself and copulation took place.

Bonobos and other animals

It has been observed of wild bonobos that they sometimes groom monkeys. Play between bonobos and monkeys has also been observed. In the Wamba area in Congo observations have also been made of bonobos playing in a less friendly way with monkeys. The bonobos seemed to see the apes as toys. They would inspect them, groom them and mount them. They even threw them in the air and swung them with their tails, causing the monkeys to bang their heads. Two young monkeys didn’t survive this rough type of play.

Other animals as food

Many different animals are being eaten as food by great apes. Chimpanzees hunt red colobus monkeys, vervet monkeys, baboons, bushbabies (where the chimpanzees make spears out of branches to impale the bushbabies in hollow trees), bush antelopes, bushbucks, warthogs, bushpigs and even human children. Watch a film about chimpanzees hunting red colobus monkeys below.

Bonobos hunt for redtail monkeys, vervets, black mangabeys, reptiles, insects, earthworms and birds’ eggs. Gorillas in the wild have only been observed to eat invertebrate animals, such as ants, termites, worms, caterpillars and snails. Orangutans eat all kinds of insects, but also small birds and mammals. They hunt grey tree rats, slow loris and even gibbons.

It has to be mentioned, though, that all great apes predominatly eat fruits and plants and other animals make up only a few percentages of their diet. Bonobos and orangutans are more opportunistic hunters, whereas chimpanzees regularly go out together on hunts. Cannibalism has also been observed in all four great apes, where young apes in particular are eaten.

Big cats and great apes

Big cats are the natural enemies of great apes in the wild. Leopards hunt all four great ape species. Lions hunt for chimpanzees and tigers on Sumatra for orangutans. The chimpanzees and bonobos drive the big cats away by hurling sticks, branches and stones and using their intimidation displays. Famous are the experiments by the Dutch ethologist Adriaan Kortlandt, who put a stuffed leopard with a baby chimpanzee doll in its claws. The chimpanzees in reaction used sticks and branches as clubs and lots of aggressive behaviour towards the stuffed leopard. Watch a short film about this experiment below.

Besides big cats, snakes hunt bonobos and crocodiles orangutans. However, for all great apes humans are the most important predator.

Conclusion: They’re just like humans

When we look at the way in which nonhuman great apes relate to cats and other animals, we can conclude the following. Although only humans keep other animals as pets for their own pleasure, nonhuman great apes that live with humans in captivity can get strong ties of affection with cats, dogs and other animals. It is, however, often necessary that the apes are under the supervision of humans when they play with other animals, because the apes often don’t know their own (much greater) strength. Negative attitudes and aggressive behaviour towards other animals also exists in great apes in captivity, where they attack cats and dogs and sometimes even kill them. Usually, however, there is an explanation for this less friendly behaviour: the apes are frightened or feel threatened or have been treated badly by humans. It seems like great apes in captivity are similar to humans: if the apes learn with human guidance to treat cats and dogs well, they will do so. Only when other motives play a part (fear, threat, negligence), will great apes in captivity treat other animals badly, which may also be the case with humans. At the same time, however, all great apes in captivity will kill and eat birds and mammals that have entered their enclosure.

Finally, in the wild, great apes will sometimes play with other animals, but often this turns to aggression. All great apes, and especially chimpanzees and bonobos, will hunt and eat many different animals. We may possibly see a link there with how our own human ancestors related to animals in the past.

Invite me to give this lecture!

If you’d like me to give this lecture at your own organization you can contact me. My email address is:


– Roger Fouts (with S.T. Mills). (1997). Next of kin. What chimpanzees have taught me about who we are. New York: William Morrow & Company.

– Jane Goodall. (1971). In the shadow of man. London: Wm. Collins.

– Jane Goodall. (1986). The chimpanzees of Gombe. Patterns of behavior. Cambridge, MA: The Belknap Press of Harvard University Press.

– Jane Goodall. (1990). Through a window. My thirty years with the chimpanzees of Gombe. Boston: Houghton Mifflin Company.

– Elizabeth Hess. (2008). Nim Chimpsky. The chimp who would be human. Nerw York: Bantam Books.

– Eugene Linden. (1981). Apes, men, and language. Harmondsworth: Penguin Books.

– Anna Michel. (1980). The story of Nim. The chimp who learned language. New York: Alfred A. Knopf.

– Francine Patterson. (1987). Koko’s story. New York: Scholastic, Inc.

– Francine Patterson & Eugene Linden. (1981). The education of Koko. New York: Holt, Rhinehart and Winston.

– Esteban Rivas. (2003). GIMME GIMME GIMME. The recent signing behaviour of chimpanzees (Pan troglodytes) in interactions with longtime human companions. Radboud Universiteit Nijmegen: proefschrift.

– S.R. Ross, A.N. Holmes & E.V. Lonsdorf. (2009). Interactions between zoo-housed great apes and local wildlife. American Journal of Primatology, 71, 458-465.

– Sue Savage-Rumbaugh, Stuart G. Shanker & Talbot J. Taylor. (1998). Apes, language, and the human mind. Oxford: Oxford University Press.

– Herbert Terrace. (1979). Nim. New York: Alfred A. Knopf.

– Frans de Waal. (2009). The age of empathy. Nature’s lessons for a kinder society. New York: Three Rivers Press.

– Frans de Waal en Frans Lanting (1997). Bonobo. The forgotten ape. Berkeley: University of California Press.



Filed under Animal Communication, Animal Ethics, Language research with animals, Lectures and courses

2 responses to “Great apes and their attitude towards other animals

  1. nice to see my draws here! eric x

  2. For those interested in seeing more of Eric’s artwork, check out his own blog: Eric’s work is for sale, contact me for more information:

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