“Theory of Mind”: Capybara Intelligence

There is a long tradition of humans trying to demean animals, their intelligence and emotions. Nowhere is this more insidious than in the field of ethology/animal behaviour. Fortunately this is slowly changing partly due to more sophisticated research technology and partly due to the enlightened research and books by eminent ethologists like Marc Bekoff, Jonathan Balcombe and Jane Goodall among others.

In his important book “Beyond Words. What Animals Think and Feel“, Carl Safina lambasts those ethologists who deny “Theory of Mind” to most animal species. He writes: “Theory of Mind is probably the most underappreciated (in other animal species), oft denied aspect of nonhuman minds.

Choco looking very happy trough

Choco enjoying the Onsen experience from the safety of the water channel. A behaviour he pioneered and which many of the junior capybaras now copy. (See below)

Theory of Mind has a number of different interpretations but broadly speaking it is the ability of an animal to pick up sensory cues which enable him/her to foresee a situation which is about to develop or which the animal wants to influence, and decide on a course of action that will allow the animal to control the outcome and secure a successful result. This means the animal understands what is about to happen and can work out a strategy in advance which it then puts into practice. Carl Safina writes “Theory of Mind basically means understanding that another can have thoughts and motives that differ from yours, or from another animal”. I have put more comments and explanations from Carl Safina on Theory of Mind at the end of this blog.

The following are some of the many examples of capybara behaviour I have witnessed which demonstrate Theory of Mind.

In August of 2015 Donguri injured her right hind leg. The pain was so great that she could barely walk and she often hopped on three legs. Immediately after her injury she made her way to the “hospital room” where sick capybaras are sometimes housed, and stood in the doorway waiting for a keeper to notice her plight and attend to her injury.

Donguri leg injury waits hospital room 2015

Donguri has injured her leg quite seriously. She hobbles to the “hospital room” where sick capybaras are sometimes treated and waits for the keeper to notice her plight.

This showed Theory of Mind. Donguri had a problem and she devised a solution. She knew that one of the roles the humans played in the lives of the capybaras in her herd was to tend to capybaras who were sick or injured. I assume that she had noticed a successful outcome to the humans’ treatment of some of these capybaras. So in going to the “hospital room” Donguri was asking for medical help, which she received with the arrival of the vet shortly after.

About two days later Donguri positioned herself in the centre of the petting area of the capybara enclosure and hobbled around in circles. I have never seen her do this behaviour before so I believe she was trying to attract attention to the fact that she was still suffering and needed more help or more medication.

You can see this behaviour in my video: “A Sad Capybara Story With a Happy Ending”.

As a corollary to this, when the keepers give a capybara a pill they always try to disguise it, sometimes hiding it wrapped in a bamboo leaf. I do not believe Donguri was fooled by this. On another occasion when she ate too many leaves of a bush that was toxic and vomited, I gave her a food pellet. She took the pellet eagerly but then hastily spat it out as if it was not what she had expected. She would have sensed my concern about her health as I sat beside her while she was obviously suffering. (Capybaras are very sensitive to human emotions.) The evidence suggests that she assumed I was giving her a pill to treat her illness, and she had no interest in a food pellet. She views me as a source of food, pellets and bamboo, and her behaviour when taking the pellet and then spitting it out indicated quite clearly that she had expected something other than a food pellet, and given the fact that she was unwell the obvious conclusion is that she expected treatment, i.e. a pill.

Choco in trough distant view

You can see Choco relaxing in the water channel under the white arrow on the left. In the foreground are the more senior capybaras enjoying the Onsen in the conventional manner

The capybaras at the top of the hierarchy at Nagasaki Bio Park control access to the Onsen bath. Most of the junior capybaras are excluded. The senior capybaras, who are all female, particularly do not want neutered male capybaras in their Onsen. Choco and Doughnut are the only neutered males. Choco came up with a solution to this problem and in doing so pioneered a behaviour which other junior capybaras then imitated. The hot water to the Onsen bath flows through a wooden channel, the width of which is about one foot. One day Choco decided to jump into this water channel where he could spend several hours relaxing in the hot water with his nose under the small pipe from which the water flows. He was thus able to enjoy all the benefits of the Onsen bath without attracting any antagonism from the senior capybaras.

This behaviour demonstrates Theory of Mind in that Choco was able to envisage and invent a new behaviour which would allow him to get what he wanted, i.e. relaxing in hot water, in a place which would not put him in direct conflict with the senior capybaras.

Choco is an exceptionally intelligent and creative capybara who has pioneered several new behaviours to the benefit of other junior capybaras.

He has learned how to open the gate to the capybara enclosure and often goes out to feast on any grass he can find. Some of the other capybaras take advantage of this opportunity to escape.

When he was only one-year-old and much smaller, he found himself near the bottom of the hierarchy. As he was not getting enough to eat, he started going inside the monkey house and eating the monkey’s breakfast. Surprisingly, the capuchin monkeys tolerated him but when other capybaras, Ryoko and Aoba, followed his example the monkeys chased them away. It is interesting to speculate on why the monkeys accepted Choco. There is no doubt he has an easy, gentle charm. He is very calm and fearless. The monkeys enjoy taunting and upsetting those capybaras who react the most and become most upset.

Choco in monkey house 2014

Choco coming out of the monkey house after eating the monkeys’ breakfast

“It is amazing how smart capybaras are and unlike most of Brazil’s fauna. They learn the dynamics of the traffic. They know when to stop and how to cross the streets.” Several of my friends who study Brazilian fauna have told me this. They have witnessed families of capybara trying to cross the busy streets. The capybaras wait until the traffic gives way.

“É impressionante como são inteligentes e ao contrário da maioria dos outros animais da nossa fauna, aprendem a dinâmica do trânsito, e como parar ao atravessar ruas. Já testemunhei algumas famílias tentando atravessar, paradas esperando até alguém dar passagem.”

When Marvin (a human) has to leave Romeo and Tuff’n alone in the house he separates them by putting up a barrier which divides the home in two. One capybara gets to be in the bedroom with access to the back garden and swimming pool while the other capybara has access to the living room and front garden. Tuff’n likes to play fight with Romeo but this escalates and Romeo sometimes ends up wounded. Marvin likes to give Romeo access to the back garden so that he doesn’t see Marvin leave. Romeo is bonded with Marvin and gets upset when Marvin leaves the home. Capybaras are herd animals and prey animals and if a member of the herd disappears it probably means they have been killed by a predator. Tuff’n is bonded with Romeo so as long as Romeo is around Tuff’n is happy, he is not upset if Marvin leaves the home. Tuff’n senses what Marvin is about to do and he knows Marvin will try and lure him into the front area. To avoid this he ensures that he is in the bedroom or back garden before the barrier goes up. Whether he prefers the back garden area or whether he just wants to do the opposite of what Marvin wants him to do rather than being controlled by Marvin, is open to debate. Perhaps, like most rodents, he just wants to be in control of his life rather than be controlled by humans.


Romeo and Tuff’n want to go to the park. They are waiting here to communicate to Marvin that it is time for them to be taken to the park. They have worked out and adopted this behaviour because they can envisage an activity which they will enjoy and they know that by waiting on this mat they will successfully communicate their wishes to Marvin.

One day Marvin was working in the garage and forgot to give Romeo and Tuff’n their afternoon corn at the usual time. On leaving the garage Marvin noticed Romeo sitting by the gate into the front garden. As Marvin entered the front garden Romeo stood up on his hind legs and put his paws on Marvin’s chest. He then looked Marvin straight in the eye. As he did so Tuff’n came over and barked “Corn, Corn”. Tuff’n usually announces the arrival of corn with a vocalisation that comes across as a realistic rendition of the word “corn”.

Tuff’n likes to play with his cushion in the pool. In order to be able to reach the cushion once he is in the pool he has to drag it to the edge of the pool before he jumps in. He then jumps into the pool, swims over to the cushion, pulls the cushion into the water and plays with it. This behaviour shows how Tuff’n is able to visualise or think through in advance a course of behaviour that will allow him to achieve his aim, i.e. pulling the cushion to the edge of the pool so that he can reach it when he is in the pool.

When Elizabeth or Marvin are injured or unwell Romeo and Tuff’n sense their suffering and come over, often laying their heads on the injured area. If their humans spend the day in bed the capybaras will spend the day lying on the bed showing an understanding of the humans’ suffering and a desire to show sympathy, affection and make them feel better. Capybaras are very sensitive to emotions, both the emotions of other capybaras and to the emotions of humans. They become very upset if humans argue in their presence. They need to be sensitive to the mood and emotional state of the other capybaras in their herd in order to avoid aggression.

Deception, the ability to deceive, is also cited by ethologists as proof of “Theory of Mind”. On one occasion I was visiting Garibaldi Rous. He had been rolling in the mud and knew that he was not allowed to go inside the house when he was covered in mud. So he took a circuitous route around the garden before suddenly veering off to the left and into the house.

In all these examples the capybara knows what is about to happen and has worked out, or invented, a strategy, a course of behaviour which solves his problem and ensures a successful outcome. This is evidence of “Theory of Mind”.

Humans often judge animals by behaviours which are appropriate to the lives of humans but not to the lives of the animals they are testing. Humans would fail miserably in many of the situations in which the different animal species excel.

As Carl Safina writes, most animal species could not go about their daily life without Theory of Mind. “The term “Theory of Mind” was coined in 1978 by researchers testing chimpanzees. With an impressive lack of human insight into what could be an appropriate context or meaningful to a chimp they devised an experiment so artificial” that, as sometimes happens, the academically generated concepts failed to elicit the capabilities that the scientists were trying to investigate. (For the full description of these absurd tests please see page 244 of Carl Safina’s book “Beyond Words. What Animals Think and Feel.” As Carl Sarafina writes “any ecologist who watches free living animals feels humbled by the depth and nuance of how they negotiate the world” and how easily they evade human observation as they go about their daily lives keeping themselves and their babies alive. Many animals, like capybaras, are highly skilled in reading body language and use other senses, including a sense of smell, to detect and authenticate a situation.

Carl Safina writes “Rather than “testing” animals in contraptions and setups where they cannot be who they are, we might simply define the concept we are interested in, then watch the animals in situations appropriate to their lives. Real life behaviours and decisions cannot always be elicited under experimental lab conditions. Do animals show an understanding that others hold different thoughts and agendas and can even be fooled? Yes. It is happening all around us. But you have to have your eyes open. Lab psychologists and philosophers of behaviour often don’t seem to know about how perceptions function in the real world. I wish they would go outside and watch.”