Tag Archives: Sue Savage-Rumbaugh signs

My lectures at the Minding Animals Conference

From Wednesday July 4 to Friday July 6 the second Minding Animals Conference will be held in Utrecht, The Netherlands, hosted by the Ethics Institute and Faculty of Veterinary Science at Utrecht University. Recently the two abstracts that I submitted for two lectures at the conference were accepted. They will be presented during two of the parallel sessions. Below are these two abstracts.

The first lecture is part of the theme Animal Capacities, session 2b: Higher order cognitive capacities in animals.

Have nonhuman great apes acquired a human language?

Since the beginning of the 20th century scientists have been interested to find out whether nonhuman great apes can be taught some form of human language. The first studies tried to teach spoken words to great apes, but failed to do so. From 1966 onwards, the Gardners started projects using sign language, with the chimpanzee Washoe as their first subject. These chimpanzees acquired signs and other projects soon followed: Patterson studying the signing gorilla Koko and Miles analyzing the use of signs by the orangutan Chantek. Other researchers such as the Rumbaughs used geometric symbols called lexigrams, teaching them to bonobos such as Kanzi. Most of the ape language researchers concluded that a form of human language had been acquired by their ape subjects. However, another project with a signing chimpanzee, the one by Terrace with chimpanzee Nim, obtained results that did not point to a linguistic explanation of the signing behaviour. This caused what has become known as the ape language controversy. What can we conclude about language in nonhuman great apes after these decades of research?

The field of ape language research has suffered from problems of method and interpretation. Many studies did not film the interactions between the apes and the humans, leaving room for errors of perception and memory and making it unable to examine the role of imitation in the apes’ utterances. Selective presentation of data has also been a major problem. The author analyzed the archives of all the projects with signing apes and found that particularly Patterson presented the data about Koko selectively, publishing data that seemed linguistic, but omitting the rest of the data that showed otherwise. The author also carried out a large, systematic study of the use of signs by Washoe and the other signing chimpanzees, analyzing hours of videotaped interactions between the chimpanzees and their longtime human companions. The results were that the chimpanzees mostly made 1-sign utterances, using object and action signs and request markers. Combinations of signs showed no semantic or syntactic structure, but consisted largely of stringing various signs in order to provoke their human companion into action. The communicative intentions of the chimpanzees’ sign utterances predominantly consisted of requests for objects and actions. Another systematic study that filmed all the behaviour, was carried out with Kanzi, demonstrating that he could understand hundreds of English spoken words. Unfortunately, no further reliable studies have been carried out. If we take the scientifically sound studies into account, we can draw the following conclusion about language in nonhuman great apes. The apes have demonstrated understanding of human words or symbols (an ability that has recently also been demonstrated in border collie dogs). When it comes to combining symbols into meaningful utterances like humans do, however, the apes do something different. They do not add a meaningful structure to combinations, but string symbols together in order to manipulate the humans into fulfilling their requests. With regard to the motivation for using symbolic communication, humans have a rich variety of different motivations for communication. The nonhuman apes, however, almost exclusively use symbols in order to request objects and actions from the human. Terrace called this an “acquisitive” motivation. These conclusions mean that it has not been possible to teach a human language to a nonhuman great ape and that a qualitative difference remains between human and nonhuman apes. A difference that may not have moral consequences, however.

The second lecture will be part of the theme Animal Ethics, session 4a: The moral relevance of socio-cognitive abilities.

Is absence of language in nonhuman great apes morally relevant?

The capacity for language has figured as a morally relevant ability in multiple animal ethics theories. Frey argued that language is a required capacity in order to have beliefs and desires and therefore interests. Carruthers claimed that language is a necessary ability to phenomenally experience mental states, argueing that nonlinguistic animals do not have sentience. In the Great Ape Project (GAP), set up by Singer and Cavalieri, the results from the studies with signing apes were used as an argument for equality among all great apes (human and nonhuman).

The author analyzed the archives of all the signing ape projects and carried out a systematic study of the use of signs by the famous signing chimpanzees. The results of his study were that there was no evidence for a linguistic capacity in these apes. If one considers all the results from the various ape language studies (including those that examine the use of lexigrams by bonobos such as Kanzi), one can conclude that nonhuman great apes are able to understand hundreds of words or signs, but when it comes to combining symbols in a meaningful way (grammar) there is no solid evidence that the ape subjects are able to do so. Also, when it comes to the motivation for (symbolic) communication it seems that there is a qualitative difference between human and nonhuman great apes. The subjects of ape language studies use symbols more as a tool to acquire things from humans rather than use it for a rich variety of motivations as humans do. Tomasello has suggested that humans are more focused on cooperation, with nonhuman great apes focusing more on competition in their communication. Until new evidence comes forth, we have to conclude, then, that only human apes have the capacity for language.

Where does this conclusion lead to, when it comes to our morality towards nonhuman great apes? The position held by Frey and Carruthers is considered incorrect. It is not our linguistic terms for different conscious states that make them phenomenally aware, but the emotional feel of various conscious states has primacy, to which we humans then add a linguistic label. Arguing for equality among all great apes based on the capacity for language, like the GAP has done, however, is also incorrect, now that these new studies have shown that there is no evidence for the linguistic claims of the ape language researchers. Nonhuman great apes thus appear to be qualitatively different from human apes. It is, however, a matter of argument whether higher cognitive abilities such as language or rich motivations for communication are morally relevant or not. The author argues that in our morality towards humans we consider qualitative differences in cognition or motivation to be irrelevant for moral equality (cf. the argument from marginal cases). Among humans, the presence of sentience or phenomenal consciousness is considered a sufficient condition for a morally equal status. In order to avoid the risk of being speciesist by limiting equality to humans only, equality should be extended beyond humans to include all beings capable of sentience or phenomenal consciousness. Thus, equality for all great apes, nonhuman and human, is still arguable, despite the absence of language in our nonhuman cousins. Indeed, with our current scientific knowledge, equality should be extended to all nonhuman animals.

I hope these abstracts have stirred up your interest. I would like to hear from you what you think of them. You can register for the conference by clicking here. A cheaper ‘early bird’ registration is still possible until April 27. Looking forward to meeting you at Minding Animals this July!


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

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: estebanyes@gmail.com


– 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

Registration for new Hovo courses now open!

In 2011 I will be presenting my course Communicatie en taal bij dieren at still further institutes of the Hoger Onderwijs Voor Ouderen – HOVO (Higher Education for older people). My course on the many wonders of animal communication and the intriguing history of scientific research on possibly teaching a human language to nonhuman animals, has received wide interest.

This new year I will be giving my course at the HOVO Brabant Seniorenacademie at their location at Tilburg University. It will consist of 10 lessons on Thursday morning, starting on 27 January and ending on 7 April 2011. For the HOVO Leiden I will be giving the course in 8 lessons on Tuesday afternoon, starting on 22 February, with the last lesson on 12 April 2011. Registration for both courses is now open. You can find more information and register by clicking here for HOVO Brabant and by clicking here for HOVO Leiden.

The programme of my course Communicatie en taal bij dieren will consist of the following lectures:

  1. Communication and human language: Characteristics and definitions. Language development in human children.
  2. Natural communication of animals. Goals and modalities. The honeybee dances. The alarm calls of vervet monkeys and prairie dogs.
  3. Natural communication of animals. The songs and calls of birds. The communication of wales and other animals.
  4. Natural communication of the great apes: chimpanzees, gorillas, orangutans and bonobos.
  5. Language research with great apes. History. Experiments with spoken language and sign language. The world famous signing apes: the chimpanzee Washoe, the gorilla Koko, and the orangutan Chantek.
  6. The ape language controversy. Research with the signing chimpanzee Nim. Methodological pitfalls and errors in interpretations and conclusions.
  7. The recent use of signs by chimpanzees in interactions with humans. Systematic study and conclusions with regard to the linguistic nature of signing by great apes.
  8. The language research with the world famous Kanzi and other bonobos who communicate with lexigrams. Interpretations and conclusions.
  9. Language research with other animals: dolphins, sealions, Alex the parrot.
  10. How did human language evolve?

The courses will be given in the Dutch language, but passive knowledge of English is required, given that some of the videos and films that I’ll be showing at the lectures are in English without subtitles. Accompanying study material will consist of a reader/syllabus with major articles or book excerpts on the subjects of animal communication and language research with nonhuman animals. The powerpoint presentation of each lecture will be made available to those attending the course.

If Tilburg or Leiden are too far from where you live, don’t worry. I am in touch with several other HOVO institutes about giving my course in the Summer or Autumn of 2011. I’m looking forward to meeting you at one of my courses!

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My work discussed in a fascinating book on the origins of human language

In 2008 MIT Press published Michael Tomasello’s book Origins of Human Communication, which was based on lectures that Tomasello gave in Paris in 2006. The book is a fascinating account of how human language may have evolved out of ape gestures. Based on the latest scientific knowledge on the use of gestures by apes and language development in human children, Tomasello makes a quite plausible and elegant argument that human language has had its origins in great ape gestural communication. This is because ape vocalizations are not learned. The vocalizations are used inflexibly, tied to the emotions that give rise to them. Great ape gestures, however, show much more flexibility and the use of gestures is learned during development. Great apes also use their gestures intentionally, they wait for a response from their conspecifics and will repeat or adjust the gestures if there has been no response. Though Tomasello has of course no clear-cut story of how exactly human language may have evolved, the argument for a gestural origin is solid, given these differences between great ape vocalizations and gestures. Tomasello divides great ape gestures into attention-getters and intention-movements. A gesture such as a mother asking her child to climb on her back, is an example of an intention movement: the movement of the gesture shows the intention that the mother wants to take place. The use of gestures by great apes is, however, limited to making requests to and demanding actions from others. In contrast, human communication includes motives for helping and sharing, which results in three basic motives of human communication: requesting (requesting help), informing (offering information) and sharing emotions and attitudes (bonding). These motives have come about because unlike nonhuman great apes, who have a comprehension of individual intentionality only (they know what the goals are of separate individuals), humans have skills for what is called shared intentionality: human individuals have a common conceptual ground, they have shared goals and attention and communicate with cooperative motives. These skills and motives arose in a context of mutualistic collaborative activities. Originally starting with pointing and using iconic gestures (pantomiming), humans experienced a “drift to the arbitrary,” eventually resulting in the linguistic conventions that we now know. Even grammar thus originated in human cooperative communication, because the human motives for informing and sharing needed the possibility to communicate about events displaced in time and space and to share further information about events and people that can only be expressed by certain aspects of grammar. mark the particular roles of participants and to relate events to one another as in stories and narratives. Grammatical constructions would have come about by a conventionalization process and there would thus be no need to infer a universal grammar such as Chomsky proposed: grammar is learned, not innate. The fact that grammar is part of every human language is because it is functional and necessary for our particularly human way of cooperative communication, not because grammatical rules are hard-wired in our brains.

I know this is a very short summary of Tomasello’s argument for the gestural origin of human language, so I advise you to read the book in order to understand his full argument. The book is written in a very clear and convincing style and is understandable for most lay persons with some academic background.

Chapter 6 is about the possible evolution of grammar and it is here that Tomasello gives ample space to discussing my work with the signing chimpanzees. He mentions that there has been a controversy about the lack of grammatical structure in the use of signs or lexigrams by the great apes in the language projects, because of a lack of systematic and quantitative data. My work with Washoe and the other signing chimpanzees has been exactly that: a large systematic analysis of the way the chimpanzees use their signs. My study is then presented by Tomasello on a par with the study of Sue Savage-Rumbaugh and Patricia Greenfield (published in 1990) of the way the bonobo Kanzi used his lexigrams. Both studies are the only ones in ape language research that systematically analyzed the videotaped behaviour of these ape subjects. Tomasello discusses the results of my study in several pages, presenting my conclusions on the communicative intentions or functions of the apes’ signed utterances and the lack of grammatical structure in the sequences of signs that the chimpanzees produced. He presents the only ordering that I found in the apes’ sign combinations: the chimps used object and action signs first, and a point (to the requested object or to the human) and signs that functioned as wild cards (pleasing the human) last. He quotes my 2005 conclusion in the Journal of Comparative Psychology:

“The object and action signs are produced first because these are the more important or salient signs of the (usually request) utterances, specifying what is requested. The request markers THAT/THERE/YOU/GOOD/HURRY are produced last because they are less important (not specifying what is requested) and function to add emphasis or to spur the human into action.” I feel great my work is being discussed in this great book and I’m grateful my hard work is now of use in theories and conclusions about ape communication and the evolution of human language.”

Michael Tomasello (1950) is a psychologist who originally worked at Emory University, Atlanta (where he did a lot of research on the apes at the Yerkes National Primate Research Center). Since 1998 he is professor at the Department of Developmental and Comparative Psychology of the Max Planck Institute for Evolutionary Anthropology (of which he is co-director) at Leipzig University, Germany. His research staff continues to do important studies on all four great ape species’ communicative behaviour and social cognition. The Koninklijke Nederlandse Akademie van Wetenschappen (Royal Dutch Academy of Sciences) has rewarded him the 2010 Dr. A.H. Heineken Prize for Cognitive Science.

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Ape language videos on YouTube

YouTube is an amazing site. It’s incredible how many videos people have uploaded to it. I use it a lot to find videos with medieval and renaissance music, which is a music genre I am especially fond of. I also love to find videos about things from my childhood and past to sit back in nostalgia. There are also quite some videos on YouTube about ape language research. I would like to draw your attention to the following interesting films and documentaries about ape language that have been put on YouTube. In 1976 the Franco-Swiss movie director Barbet Schroeder (known from films such as Barfly) made the movie Koko, le gorille qui parle (Koko, the talking gorilla). The film shows the how signing gorilla Koko lives and signs with Penny (Francine) Patterson, who taught signs to Koko and continues to study her signing up to this day. It also includes several parts with Roger Fouts and the signing chimpanzees Washoe and Ally at the Institute for Primate Studies at the University of Oklahoma, where they lived in the 1970s. You can watch the whole movie in 8 videos on the YouTube channel of tehinfidel. Click here to go to the first video of the movie and find the other seven parts of the movie. Another great ape language documentary is ChimpTalk, made by the BBC’s Horizon programme in 1993. It shows the history of the language projects with chimpanzees and has great parts showing the signing chimpanzees Washoe and Nim Chimpsky, as well as the lexigram using bonobo Kanzi. It also includes interesting interviews with the Fouts, Herbert Terrace and Sue Savage-Rumbaugh. Click here to go to the channel of Barbaste, who put the documentary there in 6 parts. Another very interesting YouTube channel with lots of ape language videos is that of J. Patrick Malone, a Ph.D. student in evolutionary psychology in Missouri. His channel is called PhD4NonhumanPrimates and includes several videos from the Gardners 1973 film Teaching sign language to the chimpanzee Washoe. Check out his channel by clicking here. The Great Ape Trust in Des Moines, Iowa, where the bonobos Kanzi and Panbanisha continue using lexigrams to communicate with humans has its own YouTube channel with multiple videos showing the apes using lexigrams. Click here to go to this channel. Finally, click here to go to my own YouTube channel. I haven’t uploaded videos there yet, but I have favorited many videos about animal communication and language research with animals and made a special playlist about this theme. Check out all of these interesting videos!

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Filed under Animal Communication, Language research with animals