What separates us from animals? What makes us special? What makes us unique? The central premise of the book is to both show how animals (‘animals’ excludes ‘humans’ here) are more intelligent than we may think, but to also challenge the ‘moving of the goalposts’ by scientists with respect to high animal cognition.

For too long, animals have merely viewed been viewed as beings that react to stimulus alone (the ‘Cartesian view of animals as dumb automatons’ championed by Ernst Mayr) or as creatures that evolved to have useful instincts (while the latter is true, it does not paint the whole picture).

This post offers a glimpse peek into animal intelligence, particularly on areas that were previously considered to be uniquely human. The questions posed in the post title and at the start of this section will not necessarily be answered. Instead, if you are interested in finding out, I would highly recommend getting the book. Instead, this serves as the highlights that I have chosen. I do not see this as a substitute for reading the book. There’s a lot that I haven’t included, particularly a lot of the commentary that brings the stories to life.

The weather outside is frightful

As the days started to get colder in early November, one morning, Franje, a female chimpanzee, decided to collect all of the straw from her bedroom. Carrying it under her arm on the island at Burgers’ Zoo, she made a nest to stay warm outside with her son. Most notably, she decided to take the straw out of her room while it was warm inside the heated building. She was not reacting to the cold, but, as one plausible explanation goes, she had anticipated the coldness that would follow based on the shivering she experienced the day prior.

So what? She must have seen someone else do it before. No, Franje had never done this before, and the experimenters had not seen any other chimpanzee do what she did, ruling out both imitation and rewards for behaviour. Was this a sign of future planning? That’s too big a leap to make from one observation alone, but it does strongly hint at that.

We hit the jackpot

This is one of my favourite stories from the book. At Burgers’ Zoo one morning, scientists showed chimpanzees a crate filled with grapefruits. The colony was in the building at the time, where it spends the night, which is connected to a large island, where they spend their day. The apes were interested in watching the crate being carried through a door that led to the island. When the scientists returned to the building with an empty crate, pandemonium ensued. Twenty-five apes started “hooting and hollering in a most festive mood, slapping one another’s backs”. De Waal notes that he had previously never seed any animals so happy about food that wasn’t there. The apes deduced that the grapefruits must be on the island to which they would be returning to the next day. Trial-and-error learning is ruled out since this was the first time (and a one-off event) that this procedure happened.

Many apes ran straight over the point where the experimenters had hidden some grapefruits in the sand. The only way to know was from a few yellow patches that were visible. Like the others, Dandy, a young adult male, did not slow down after running over the spot. However, when the others started falling asleep in the sun, Dandy went back to that spot and dug it up to retrieve the precious grapefruits. Had he retrieved them when he first saw them, he would likely have lost them to the dominant males in his colony.

Small acts of kindness

Here’s just one example mentioned described in the book. The primatologist Jane Goodall observed how the daughters of Madam Bee, a chimpanzee in the wild, had grown too old and frail to climb into fruiting trees herself. Her daughter would kindly bring her some in addition to collecting some for herself. This shows that apes are not only able to devise ingenious solutions but also are able to comprehend another’s problem. That’s a fundamental ingredient in kindness and one we likely take for granted in ourselves.

Tool use

Humans are tool masters. Surely that’s what separates us from the rest of the animal kingdom?

“I feel that scientists holding to this definition [of humans being the only tool bearers] are faced with three choices: They must accept chimpanzees as man, they must redefine man, or they must redefine tools.” – Louis Leakey

Here is one example out of many from the book of tool use shown by animals. Apes get most of their nutrition through seasonal fruits. When the supply of these is low, they opt for either nuts or palm pith. The latter is obtained through “pestle pounding”: a chimpanzee will stand on the edge of the tree crown, knocking the top with a leaf stalk. This makes a deep hole that the fibre and sap can be retrieved from. Chimpanzees rely on tools in order to survive.

As with all apes, chimpanzees appear to think before they act. This is especially the case for orangutans, but this also true for chimpanzees and bonobos despite being prone to being overexcited. They all seem to consider what effect their actions will have. This translates to being able to figure things out in their head instead of having to resort to trying it out to see if it works. As with our own species, a combination of the two – thinking about something and using trial-and-error – is used.

Empathy

Empathy is crucial for survival, and is something that we share with all mammals. Similar to how human parents need to be attuned to the desires of their children, mammalian mothers have to be sensitive to the emotional states of their offspring. Are they cold? Hungry? In danger?

On one occasion, an alpha male chimpanzee saved the life of a juvenile at a Swedish zoo. The juvenile had entangled himself in a rope and was choking to death. The alpha lifted the youth up (removing the rope’s pressure on the juvenile’s neck) and carefully unwrapped the rope from his neck. This required the alpha to understand the suffocating effect of ropes. If the alpha had pulled at the juvenile or the rope, he would have only made matters worse.

At the Burgers’ Zoo, the keepers had hosed out some rubber tires when cleaning and hung them all on a horizontal log that extends the climbing frame. The chimps usually use these tires as drinking vessels. A female chimpanzee, Krom, wanted one of the tires that still had water in it. The tire she wanted was at the end of the row. She was unable to remove it by pulling at the tire. For over ten minutes, she kept on trying to pull the tire out while the other chimps ignored her. That is, all except Jackie, was a seven-year-old that Krom had taken under her care as a juvenile. As soon as Krom decided to give up and walk away, Jackie approached the tires and started pulling the tires in front of the last one off the log. When he got to the last one, he carefully took it off the log to avoid spilling any water and handed it straight to Krom. Without acknowledging Jackie in any way (which is saddening), Krom started scooping the water out of the tire as Jackie left. This showed that Jackie was able to both understand what Krom had wanted and was thoughtful enough to help her out.

Capuchins can be generous and are social eaters, like our species, sitting together in groups eating. When a pregnant female hesitates to go to the floor to collect her own fruits (capuchins are arboreal, and so feel safer higher up), other monkeys have been observed bringing more than they need and giving her some.

In one experiment, capuchins were separated with a mesh wide enough for them to push an arm through. One of the monkeys was given a small bucket with apple slices. The monkey with the apples usually shared some food with their empty-handed counterpart. They would sit next to the mesh divide and let the other one take food out of their hands or mouth. What is most astonishing about this is that the monkey with the apples did not need to share one slice; they could have stayed far away from the mesh and devoured the apples by themselves. If a capuchin saw that another had already eaten, however, it would not want to share any food with the other. On the other hand, if a monkey’s partner had already eaten without the other’s knowledge, the provisioned monkey would still share with the other. Food is precious, and a monkey would not want to share it with a monkey that it thinks is sated because it just saw it eat a large meal.

Finders keepers

Charles Menzel let a female chimpanzee called Panzee watch as he hid food in the pine tree forest surrounding Panzee’s enclosure. Menzel would dig a hole in the ground to hide M&Ms or put a piece of candy in some bushes. Panzee was in her enclosure while Menzel was hiding the food and, therefore, required help from humans to retrieve the desired food item. Sometimes, Menzel would hide food after everyone else had left, which meant that Panzee had to wait until the following morning to see anyone that she could try to recruit for her cause. The following morning, the caretakers arrived, unaware of the experiment Menzel was conducting. In general, the caretakers have a high opinion of the apes’ mental skills, which is important because it meant that they would take them seriously. At first, the caretakers were surprised by Panzee’s behaviour but understood before long what she wanted them to do. Panzee would point, beckon, pant and call to help the caretakers find the items in the forest. Absent of her instructions, the caretakers would be none the wiser about where to look. Panzee never pointed in the wrong place or asked them to go to a place they had already visited, showing a clear ability to recall where the items were and what had already been found. This is much harder than it sounds. Don’t forget that Panzee had to communicate with a member of another species.

One young female grunted at De Waal from behind a fence with shiny eyes (suggesting she knew something) alternated with pointed stares at the grass near De Waal’s feet. De Waal was confused about what the young female wanted until she spat on the grass. This helped him notice a small green grape in the grass. After giving her the grape, she ran to another spot and repeated her actions to collect three grapes that the caretakers had dropped.

Aping

Victoria Horner and Andrew Whitten ran experiments on twelve orphan chimpanzees at Ngamba Island, a sanctuary in Uganda. The juvenile chimps grew attached to Horner and started to follow her lead. In this experiment, apes proved smarter than humans. Horner would show the juveniles that pushing a stick into holes in a plastic box would make candy come out of those holes. The catch here was that there was only one hole that actually released any candy. When the box was made out of black plastic, it was too hard to determine which holes were the dummy holes. With the transparent box, it was clear. With the transparent box, the chimpanzees only followed the steps Horner made on the hole that released the candy. By constrast, human children copied everything that Horner did, including the moves that led to no candy on the dummy holes. This highlighted that the human children did not grasp the problem itself and resorted to mere imitation to get the candy. The apes, on the other hand, displayed selective copying.

The word fashion was coined by Köhler in reference to animals. His apes used to invent new games regularly. They would march in single file around a post, in synchronisation to the same rhythm. They focused on stamping one foot while the other touched the ground lightly. If this wasn’t amusing in and of itself, they also moved their heads from side to side in the same rhythm. Or as De Waal puts it: “as if in a trance”. One meme was observed in a chimpanzee sanctuary in Zambia where one female was the first to place a strand of grass into her ear. As years went by, other chimpanzees copied her “look”.

Some alpha males would storm around while banging on a metal door to make his presence be heard. It is a scary thing to behold; mother chimpanzees keep their children close by. After the alpha male is finished, young infant males would copy their role model by banging on the same door.

Social skills

Hierarchy is everything with chimpanzees. When two females are tested inside a building at the same time, one will go through the task while the other will wait. The latter hardly takes rewards and does won’t even touch the puzzle box, computer or whatever apparatus is being used. The reason for this isn’t to do with interest: the second female may be equally (if not more so) eager to carry out the task than the first. It is a matter of submission. The second “knows her place”, so to speak, and allows the first to dominate. This holds true even if the two females get along well out in their group and are the best of friends.

Conflicts are hardly ever just between two individuals. Chimpanzees tend to bring others into the fold. There could be ten or more chimpanzees running around, threatening and chasing one another. Every individual tries to form as many allies as possible to strengthen their position. Chimpanzees that were losing would try to recruit their friends by stretching out an open hand in desperation. They also were proactive in trying to mollify the friends of their rivals. To know who the friends of your enemies are requires ou not only to recognise your relations with B (your enemy, say) and C (the friend of your enemy, B) but also how B and C relate. De Waal refers to this interconnected triangle as triadic awareness. He also points out that without triadic awareness, human society could not operate.

Captive chimpanzees go beyond respecting those of higher rank to themselves. When the director of a zoo visited and started ordering people around (e.g. telling them what need to be cleaned, what needed to be moved, what could be done better, etc.), he portrayed himself as the alpha that others feared and were submissive to. Even though the chimps had hardly interacted with him, they treated him with the utmost respect by making submissive grunts to him from far away, something that they did not do for anyone else.

Cooperation

In the 1930s, Meredith Crawford ran an experiment to test the cooperation on apes. Food had been put on top of a box. Two youngsters, Bula and Bimba, had to pull at the ropes attached to their box outside their cages. However, the box was too heavy for one of them to pull by themselves. Their pulling was astonishingly synchronised (De Waal describes as “so well coordinated that you’d almost think they were counting – ‘one, two, three … pull!’”). In the second part of the test, Bula had been fed so much that she wasn’t as motivated to pull so much to get more food. Bimba got her compatriot to help by pushing Bula’s hand towards the rope or by a poking her. After the food had been reached, Bula didn’t collect much and left nearly all of it to Bimba. Why did Bula work so hard if she wasn’t interested in the reward? Reciprocity is the likely answer. Bula and Bimba live together, and so she did a favour for her friend with the expectation that when she next needs help, Bimba will be there for her. The cooperative pulling paradigm has also been tested on monkeys, hyenas, parrots, rooks, elephants and more.

Primates tend to prefer partners that cooperate eagerly and share the rewards. Capuchin monkeys tend to share more food with a partner that helped them retrieve the food than a partner whose (little) help was not needed. When chimpanzees go hunting, they prefer to share with fellow hunters than those that did not participate. The alpha male is not excluded here – if he didn’t help, he doesn’t deserve any. No free riders.

Chimpanzees are considered by some to be violent and aggressive. This description is based on how they treat neighbouring clans in the wild. This should not be an argument against their cooperative nature, though. On average, the murders on a field site occur every seven years. We should not forget that our own species considers forming allies and going to war as being cooperative. Chimpanzees hardly ever attack neighbours solo. Scientists not too long ago tested chimpanzees’ cooperation at the Lincoln Park Zoo in Chicago. They were able to fish for dipsticks for ketchup stored in holes in an artificial termite mound. At the start of the experiment, there were enough holes for everyone to fish by themelves. Every day, one hole was removed. Before long, there were hardly any. The holes could have been monopolised by a greedy chimp, but that wasn’t the case. Each chimpanzee took turns and patiently waited for their turn. That may seem to be the polite sort of thing that the British do, but I’m not sure. If we were tested and there was a scarcity of food (assuming we didn’t know it was a short-lived experiment), I reckon pandemonium would ensue, with more pushing and shoving than what you see in the Tube (London underground) at rush hour. Nonetheless, there’s no doubting that human cooperation is on a level of its own. We have organised ourselves at scale at a level not seen (as of yet, anyway) by any other species in nature.

Do animals think about the future?

Monkeys utilise their past experiences to make future ones, such as whether there is a safe landing pad for their jump between two trees, whether the branch is strong enough to handle the impact and so on. These are critical life-and-death decisions for them. The matriarch of an elephant herd in a drought may suddenly recall a drinking hole miles away that only she knows about. The other elephants trust her, and it may take days to reach the place where the water is. From a survival perspective, animals cannot afford to remain in the present because the present is ephemeral. However, most of the time, they think only about the near future, as opposed to the distant future.

In the 1920s, Edward Tolman, a psychologist, bravely declared that he believed that animals were more than stimulus-response machines. They are not purely driven by incentives. Otto Tinklepaugh, Tolman’s student, designed a test for this. A macaque watched someone place a leaf of lettuce or a banana underneath a cup. As soon as the macaque was released, they would go straight for the cup with the hidden food. However if the experimenter replaced the banana with the lettuce without the macaque knowing, the macaque would simply stare at the reward. The macaque would then start angrily shrieking at the experimenter’s deceitfulness. It would take a while until the macaque had calmed down and opted for whatever the lousy reward was. This was strange because animals were meant to connect behaviour with any reward. It shouldn’t matter what the reward was.

De Waal and others tested an adolescent chimpanzee called Socko with a hide-and-find test. Through a window, Socko would watch a human hide an apple in a large tractor tire in the outdoor enclosure while the rest of Socko’s colony was kept inside and away from sight of the outdoor enclosure. The colony was then released, with Socko being released. He first went into the tire, checked the apple was still there and then left it alone and walked away. After twenty minutes, everyone else was occupied. The coast was clear. He then went to collect the apple. Had he took it straight away, he could have lost it to a more dominant chimpanzee. This test with Socko was only done once. Years later, the test was being redone. Socko was now the alpha male, so could not be chosen. As the alpha, he would have no reason not to consume the fruit straight away since no mortal chimpanzee would dare question him. A low-ranking female called Natasha was chosen, instead. The experiment was nearly the same as before. Natasha watched through the window and was the last to be released. This time, a hole was dug into the ground, and the apple was buried. The spot was then covered with sand and leaves. The concealment was so good that the humans hardly knew themselves where they put the fruit. Natasha knew, though. She walked over the spot and waited ten minutes until she felt she wouldn’t be disturbed. While she started to dig up the fruit, Socko watched Natasha with awe. “It is not every day that someone pulls an apple out of the ground”, as De Waal puts it. Instead of approaching Natasha and claiming the apple for himself, he ran straight to the tire and looked in the tire for an apple. He felt that if food was being hidden, the humans might have hidden it in the same place as before. This was after one experience that had happened five years before this incident with Natasha.

This may be a coincidence, but Gema Martin-Ordas has been testing the memory capabilities of lots of chimpanzees and orangutans to see how much they could remember from past events. The apes had to find the appropriate tool to retrieve either a banana or a frozen yoghurt. The apes had seen the tools being hidden in the boxes. They had no problem with this task. Three years later, after having gone through numerous other tests, the apes were sent to the same room with the same setup. The investigator present was also the same as before. The apes that had taken the test three years ago knew exactly what tool they needed and where to find it, solving the problem in seconds.

Karline Janmaat found that apes (in the Taï National Park in the Ivory Coast) had stellar memory of where they had eaten before. They predominantly checked trees where they had eaten before in previous years. If they found lots of ripe fruit, they would make a mental note and return a couple of days later.

Chimpanzees, like many teenagers, despise waking up before dawn. Yet, Janmaat observed a group making a long expedition to a particular fig tree where they had previously eaten. They left early to avoid the fig rush. Figs are sweet fruits that many forest animals, squirrels and hornbills among them, crave. By arriving early, they ensured they had access to as much as their empty stomachs desired. Even more impressively, they would wake up earlier if they had to travel further. This implies that they account for the time it takes to reach their destination when planning travel routes.

But what makes us unique?

All right, animals are intelligent. “But what does it mean to be human”. As De Waal points us, the “but” is telling. It is asking the responder to forego all similarities and pinpoint what differentiates us from our distant relatives. De Waal uses an iceberg metaphor: there is a large space of cognitive, emotional and behavioural similarities between us and the primates. The differences lay in the tip of the iceberg, where there are only a few dozen differences.

Mirror, mirror on the wall, who is the smartest of them all?

The debate with what the big difference is has been said to be opposable thumbs, cooperation, humour (seen a chimpanzee lately?), altruism, language or the anatomy of the larynx. The debate may have begun with a debate between Plato and Diogenes about a succinct definition of the human species. Plato proposed that humans were the only creatures that were at once naked and walks on two legs. Diogenes responded by bringing in a plucked fowl into the lecture theatre, letting it loose while announcing “Here is Plato’s man”. The definition was then extended to include “having broad nails”.

If I haven’t convinced you already…

Imagine seeing an animal and thinking of it in a completely different way to how you did before. That’s how I feel having now read this thoroughly insightful and accessible book.