One month before Mama the chimpanzee turned 59 and two months before Professor Jan van Hooff’s 80th birthday, these two elderly primates, who had known each other for more than 40 years, had an emotional reunion.
Mama, emaciated and near death, was the long-time queen of the chimpanzee colony at Burgers’ Zoo in the Dutch city of Arnhem.
Jan, with his white hair standing out against a bright red rain jacket, was the biologist who set up that colony in the Seventies and wanted to make one final visit to its ailing matriarch.
Many emotions long-thought to be uniquely human can be found in all mammals, from voles to elephants, dolphins and whales. Dogs (file image) trained to lie still in MRI scanners show the same brain activity when they are expecting to be given a frankfurter to eat as businessmen have when they’re promised a monetary bonus
This was a first for them both. Even though they had shared countless grooming sessions through the bars of her night-cage, chimpanzees are so mercurial that the only humans safe in their presence are those who have raised them.
That was not the case for Jan with Mama, but the fact she was so weak changed the equation.
As Jan approached with a few friendly grunts, Mama remained curled up in a foetal position in her straw nest and didn’t look up. But when she did see Jan, her face broke into an ecstatic grin and she yelped the soft, high-pitched sound reserved for moments of great emotion in chimpanzees.
Reaching for him as he bent down, she stroked his hair gently, then draped one of her long arms around his neck to pull him closer, rhythmically patting the back of his head in a comforting gesture that chimpanzees use to quiet a whimpering infant.
Research has shown Chimpanzees are one of the key species in showing gratitude. They are complex creatures, are always seeking dominance and demonstrate human expressions
She had sensed his trepidation about invading her domain and was letting him know not to worry. She was happy to see him.
Mama died a few weeks later, and when Jan’s video of their goodbye was seen by millions of YouTube viewers worldwide, people were profoundly moved by the way she had embraced him.
It made them realise that a gesture that looks quintessentially human is, in fact, a general primate ‘pattern’, and it’s often in the little things that we best see the evolutionary connections between other species and ourselves.
Those connections apply to 90 per cent of human expressions, from the way hairs stand up when we are frightened, to men — and male chimpanzees — slapping each other’s backs in exuberance. The connections are found in many other mammals, too, because our bodies all have the same basic structure. Indeed, our brains are generally so similar that the treatment of human phobias is based on studies of how fear manifests itself in the brains of rats.
Dogs trained to lie still in MRI scanners show the same brain activity when they are expecting to be given a frankfurter to eat as businessmen have when they’re promised a monetary bonus.
Scientists are gradually beginning to accept that humans are not the only species with the capacity to feel emotions.
After four decades of research into animal behaviour, including thousands of hours watching Mama and the other chimpanzees, the question for me has never been whether or not animals have emotions, but how science could have overlooked them for so long.
I believe that many emotions long-thought to be uniquely human can be found in all mammals, from voles to elephants, dolphins and whales.
Chimpanzee who showed GRATITUDE
During the time I was observing Mama, I never saw a single disagreement between her and Kuif, her female sidekick and best friend. They groomed each other frequently and always supported one other. My own relationship with Kuif, however, was fraught.
Chimps are always seeking dominance, and Kuif often tried to grab me aggressively. But then things improved.
She had lost several babies because she couldn’t produce enough milk. Every time one died, she went into a depression, rocking and making heart-rending screams. Seeing her suffer again and again, I taught her to bottle-feed and, from then on, she became the most caring mother imaginable. She would even remove the bottle if the infant needed to burp — something we hadn’t taught her.
After this, Kuif showered me with affection whenever she saw me. I took this as a sign of gratitude, an inference supported by the behaviour of Wounda, a chimpanzee rescued from poachers and cared for at a rehabilitation centre in the Republic of Congo.
A video of the moment Wounda was released back into the forest in 2013 shows her walking away, then returning to hug the people who had taken care of her, as if realising it wouldn’t be nice to disappear without thanking them.
There are similar accounts of netted or beached dolphins and whales who were rescued by human divers. Many have returned to their rescuers and nudged them or lifted them half out of the water before swimming off — the cetacean way of saying ‘thank you’.
The grumpy dog who had Food envy
Researchers at the University of Vienna have shown that dogs are fully capable of envy.
First, the team at the Clever Dog Lab trained two dogs to offer up a paw for no reward. Both were happy to do so. But if one dog received a piece of bread, the other would give up and refuse. Capuchin monkeys behave similarly.
Dogs (file image) are capable of envy, according to researchers at the University of Vienna. Clever Dog Lab trained two dogs to offer up a paw for no reward. Both were happy to do so. But if one dog received a piece of bread, the other would give up and refuse
Looking for their sense of fairness, I once placed two monkeys side by side and asked them to perform a simple task in return for slices of cucumber. They happily did so. But when I started rewarding one monkey with a grape instead, there was drama.
Even though her reward was unchanged, the one still receiving cucumber went ‘on strike’ and began hurling the slices at me.
Incidentally, when I published a short video of that experiment online, it went viral.
People recognised their own behaviour in the monkey’s and wrote to tell me they had forwarded the clip to their bosses to let them know how they felt about their salaries.
Why voles can feel broken-hearted
The standard way to dismiss animal feelings is to shift the argument on to biological imperatives. If you propose that an animal shows pride, you’ll be told that it just puffs itself up to look larger and more intimidating, whereas if you suggest that an animal is afraid, you will hear that they don’t need to feel fear as long as they can escape danger.
Above all, if you suggest two animals love each other, the answer will be that they don’t need to because all that matters is reproduction. Even if we view human romantic love as special, the neural mechanisms involved in creating bonds within other species are strikingly similar to our own.
The meadow vole lives a promiscuous life while the prairie vole forms pairs in which male and female mate exclusively and raise pups together
People in love have higher levels of oxytocin in their blood than single people. The hormone’s functions include shielding us from sexual experiences with outsiders. When married men are given oxytocin in a nasal spray, they feel uncomfortable around attractive women and prefer to keep their distance.
The same hormone shapes the love lives of two species of vole found in North America. While the meadow vole lives a promiscuous life, the prairie vole forms pairs in which male and female mate exclusively and raise pups together. The latter have far more oxytocin in their brains, resulting in an intensely positive association with sex and an ‘addiction’ to the partner they mate with.
Prairie voles (file image) have more oxytocin in their brains, resulting in an intensely positive association with sex and an ‘addiction’ to their partner than other vole species
If they lose their mate, they show chemical changes suggesting stress and depression and become passive in the face of danger, as if they don’t care any more whether they live or die — the vole’s equivalent of a broken heart.
Mammals that really care
You’ll have heard of guide dogs, but perhaps not of a seeing-eye elephant such as Mae Perm, the resident of an open-air sanctuary in Thailand. Whenever her blind friend Jokia was upset or spooked, Mae Perm would rush to her side, make reassuring noises and caressing her with her trunk or placing it in the other elephant’s mouth.
This made her very vulnerable (nothing is more sensitive and important to an elephant than the tip of its trunk) and Jokia did the same by placing her trunk into Mae Perm’s mouth.
Chimpanzees anticipate others’ needs and seek to make them feel comfortable. Whenever Mae Perm’s blind friend Jokia was upset or spooked, she would rush to her side at an open-air sanctuary in Thailand
When I was studying bonobos at San Diego Zoo, the keepers had cleaned the moat surrounding their enclosure and were about to refill it when the group’s alpha male, Kakowet, started screaming and waving his arms at them, almost as if he was talking.
It turned out that several young bonobos had jumped into the dry moat and couldn’t get out. Since apes don’t swim, they would have drowned, but thanks to Kakowet they were all rescued with the help of a ladder, save the smallest one who he pulled up himself.
This anticipation of others’ needs was also seen at the American primate research centre where I have worked for 25 years. When our former alpha male, Amos, was dying, a female called Daisy often visited him in his bedroom, tenderly grooming him and stuffing soft wood wool between his back and the wall.
It was as if she realised he was in pain and would be better off leaning against something comfortable, like the way we arrange pillows behind a patient in the hospital — behaviour that in humans would certainly be attributed to sympathy.
Apes love a bit of slapstick
Aristotle thought that laughter was what set humans apart from beasts, and many psychologists still doubt that any animal laughs for joy or because something is funny.
But it’s well known that apes love slapstick movies, probably because of all the physical mishaps. When a person they like walks toward them and slips, their first reaction is worried tension, but if the person turns out to be fine, they laugh with apparent relief, the way we do in similar circumstances.
Apes understand jokes of deception as well as having an appreciation of slapstick movies because of all the physical mishaps
In my experience, chimps certainly do have a sense of humour. At Burgers’ Zoo, a colleague once tested their response to predators by donning a panther mask.
Always alert, Mama and the other chimpanzees pelted the ‘predator’ with sticks and stones until, after several confrontations, he took off the mask to show his face.
At that point, Mama’s angry expression changed to a laughing face which she held for a while, suggesting that she saw the joke of his deception.
Jackdaw who mourned its mate
There are many stories of dogs’ loyalty to their owners even in death, including Greyfriars Bobby, the terrier who guarded the grave of his owner in Edinburgh for 14 years, before his own death in 1872.
The same loyalty apparently drives other animals. Elephants will gather the ivory or bones of a dead herd member, holding the pieces in their trunks and passing them around.
Terrier Greyfriars Bobby is an example of dogs’ loyalty as he spent 14 years guarding the grave of his owner in Edinburgh. Here a statue has been made of the beloved dog to pay tribute
One chimp mother in a West African forest carried her dead infant for 27 days.
Dolphin mothers may keep a dead calf with them for days, and comparable behaviour has even been seen in birds.
When the mate of one of my tame jackdaws disappeared, he called for days while scanning the sky. When she failed to return, he gave up; and when he died a few days later, it was my turn to mourn.
And the elephant in the room . . .
The possibility that animals experience emotions like humans do makes hard-nosed scientists feel queasy.
For many years, it was suggested that consciousness depends on the number of neurons in one’s brain, so the recent discovery that elephants have three times more such nerve-cells than us could trouble those scientists.
Do we need to rewrite the story of human consciousness? What proof is there actually that we are more conscious than the elephant?
Elephants (pictured in Ayutthaya on December 23) have more genes dedicated to smell than any other species which makes the common thought that the mammal is less aware of its own physique and surroundings come into question
This animal has a three-ton body and 40,000 muscles in its trunk alone (not to mention a penis with which it can pick up objects); it must carefully orchestrate every step (think of tiny calves walking between the legs of their mothers) and has more genes dedicated to smell than any other species.
I would question how certain we can be that the elephant is less aware of its own physique and surroundings than we are. But of course it has long suited us to assume that animals are dumb automatons devoid of feelings and awareness, as science has done for a long time.
This animal (pictured at the Addo Elephant National Park) has a three-ton body and 40,000 muscles in its trunk alone
That they are not, presents us with a serious moral dilemma, and in this era of factory farming, animal sentience is, you might say, the elephant in the room.
There are thousands of animals in zoos, millions in labs, and millions more in human homes, but literally billions and billions in the farm industry.
I am too much of a biologist to question the natural circle of life and I have no problem with meat-eating in itself. But there is a lot wrong with how we treat, raise, transport and slaughter animals. The conditions are often degrading and sometimes plainly cruel and for that reason I have banished nearly all mammalian meat from my kitchen.
In my professional life, I hope to do far more. It’s up to scientists like me to push for a new appreciation of our fellow travellers on this planet and help make a reality of my prediction that a science of the emotions will be the next frontier in the study of animal behaviour.
Adapted from Mama’s Last Hug by Frans de Waal, published by Granta at £14.99. © Frans de Waal 2019. To order a copy for £12 (offer valid to January 10, 2020; P&P free), visitmailshop.co.uk or call 01603 648155.