Jonathan Balcombe was born in England, raised in New Zealand and Canada, and has lived in the United States since 1987. He has three biology degrees, including a PhD in ethology (the study of animal behavior). Formerly De­part­ment Chair for Animal Studies with the Humane Society University, and Senior Research Scientist with the Phys­icians Committee for Responsible Medicine, Jonathan is currently Director of Animal Sentience with the Humane Society Institute for Science and Policy, in Washington, DC.

Jonathan has published more than 50 scientific papers on animal behavior and animal protection and has contri­buted numerous articles to scientific journals, magazines, and blogs on a variety of animal issues including, animal wel­fare, animal behavior, animal research, and veganism. He also speaks all over the world at conferences, cam­puses, and other venues, including a recent TEDx talk on the inner lives of fish, and has written five books on animals, four of which explore the inner lives of animals (Pleasurable Kingdom, Second Nature, The Exultant Ark, and most recently, What a Fish Knows), with scientific and anecdotal proof that animals do not exist merely to survive and procreate, but that they have independent, fulfilling lives rich with emotion.

We are privileged to discuss all of this with him.

What do you think are the primary reasons fish are so often unrecognized as sentient?
Relatively speaking, fishes are alien to our sensib­ilities. They evolved in a very different physical milieu to ours. Living in water, fishes don’t trigger our sympathies the way mammals do. We can’t hear the sounds they make when they are upset or in pain, and they don’t blink (they don’t need to since their eyes are constantly bathed in water). It was only in the 20th Century that technological advances in SCUBA and underwater photography were able to witness the com­plexities of fish life. Little wonder that most humans con­tinue to think, falsely, that fishes are primitive and dim.

Humans often unfairly judge non-human intelli­gence based on human tasks; thinking animals are perceived as not so intelligent because they don’t act like humans. The truth is, as you point out, all animals are intelligent in the things they need for survival in their environments and circumstances. And many non-human animals demonstrate extraordinary intelligence. Can you give us some examples of fish intelligence? What are some amazing things people don’t realize fish can do?
Not only has science essentially put to rest the malevolent myth that fishes do not feel pain, science is also showing that fishes are intelligent, emotional, even Mach­iavellian. Among their achievements, fishes have person­alities; they plan, recognize, remember, court, play, parent, innovate, manipulate, collaborate, communicate with gestures, keep accounts, show virtue, form attachments, possess culture, fall for optical illusions, use tools, learn by observation, form mental maps, and behave differently according to who’s watching (so-called audience effects).

Here’s a bit more detail on some of these capacities:

• On reefs, a hungry grouper fish will use a headshake signal to recruit a moray eel to go hunting. Working as a pair, they each have higher per capita hunting success than hunting alone. Groupers will also point to hidden prey, seek­ing to get the eel’s attention. Such “referential signaling” is only known from a handful of other, big-brained animals.
• Fishes have good memories, recognizing preferred shoal-mates probably for life. A recent study showed that archer­fishes recognize individual human faces. (They “voted” by squirting water at familiar images presented on panels above their tank.)
• Captive cods showed innovation and tool-use when some began to use the plastic tags on their backs to hook into a dangling food dispenser loop to get food slightly faster than if they tugged the loop with their mouths.
• Cleaner fishes outscored great apes (chimpanzees and orangutans) and monkeys (and a fish researcher’s 4-year-old daughter) on a cognitive task involving ephemeral and permanent food sources.
• Herrings communicating by farting. (no kid­ding!)
• Various fishes fall for the same optical illusions we fall for, indicating that a fish has beliefs and that these beliefs, like ours, may be fallible.
• Fishes feel pleasure. Groupers, manta rays, moray eels, and various sharks are among many kinds of fishes that will approach trusted divers to be rubbed and stroked.

There is a perception that intelligence is part of sentience, although it is not the case. Even so, do you think if people knew how intelligent fish are, it would be easier for them to accept that fish are sentient?
In my writing and speaking about animals, I am hoping that the information spawns reflection and, in turn, behavioral change. Research shows that many people never­theless remain so entrench­ed as to be unmoved by informa­tion. However, there are many open-minded “fence-sitters” who can be affected by new information, especially when it has the stamp of legitimacy that science provides. And I believe it is that demographic that makes up most of my audiences.

In What a Fish Knows, you often specifically note when fish are unharmed by experiments and when they are released afterward. I did worry, as I read, about the fish used for study and found comfort in these notations. How do you reconcile the need to use fish to learn about fish, especially in the situations where the outcome for the individuals is not a good one?
I wish it were routine for researchers to treat their subjects with respect, and to work under the principle of virtually no harm. In reality, many of the studies I cite do cause harm. I cite them in hope that their findings will ultimately serve fishes by advancing our respect and appre­ciation for their lives. But, in doing so, I make sure to qualify that my citing a given study is not synonymous with an endorsement. Scientists are innovative, and I believe we can design studies to demonstrate all aspects of animal intelli­gence and emotionality without deliberately harming ani­mals. I laud the growing number of scientists who are striving to adhere to that principle.

“Fishes are alien to our sensib­ilities. Living in water, fishes don’t trigger our sympathies the way mammals do. We can’t hear the sounds they make when they are upset or in pain. Little wonder that most humans con­tinue to think, falsely, that fishes are primitive and dim.”

You have said that, historically, science has been reluctant to attribute consciousness to any­thing other than humans. It is often argued that a fish’s reaction to pain is simply a stim­ulus response. Numerous studies have proven that fish do have a pain response, which re­quires conscious recognition of pain. Science has proven fish consciously feel pain. What are some of the studies proving this?
A 2010 book by Pennsylvania State Uni­versity fish biologist Victoria Braithwaite titled Do Fish Feel Pain? summarizes detailed experiments conducted on anesthetized trout showing they have the same types of differentiated nerve receptors for mech­anical, chemical, and heat stimuli that we have. Also, that these receptors send signals to the fish’s brain, and that, in turn, behavior changes indicating aversion to these noxious stimuli. Gill beats increased following an injection with acid, but not so much following an injection with a mild saline solution. Acid treated fishes also spent more time hanging near the bottom of their tank, they took longer the resume feeding, and some fishes rubbed the injected area against the gravel or aquarium glass, as if trying to soothe it. The trout also lost their normal fear of a foreign object (a construction of Lego blocks) placed in their tanks. Thus, a putatively painful stimulus (vinegar) appeared to impair trouts’ ability to perform a higher order cognitive behavior—awareness and avoidance of a novel object. The research team conjectured that the pain of vinegar so dis­tracted the afflicted trout that they were unable to perform normal survival behaviors.

What I find most convincing of fish pain studies is that known painkilling drugs suppress the apparently painful responses. For example, abnormal behaviors vanished and feeding resumed much sooner if acid-treated trout are given pain relief. In a clever study by another fish pain expert, Lynne Sneddon of the University of Liverpool, zebrafishes injected with painful acid were willing to pay a cost to get pain-relief. Individuals who had received an acid injection swam into a normally avoided barren chamber of their tank, but only after Lidocaine had been dissolved there; zebra­fishes injected with benign saline solution continued to avoid the barren chamber. For a recent, in-depth discourse around the so-called fish pain “debate,” I direct readers to dozens of commentaries in the open-access journal Animal Sentience.

Given these studies, why do you think there is still a debate? Are people reluctant to believe fish feel pain and, if so, why?
Fish pain is an inconvenient truth. It is both practic­ally and morally easier to continue activities that harm a victim when one believes the victim unworthy of consider­ation. Many people—commercial fishers, aquaculturalists, aquarium collectors, supermarket chains, and of course, consumers—profit or otherwise gain from the belief that fishes are incap­able of pain and suffering.

I was especially surprised to learn that fish are not silent, that in reality they have more ways of producing sound than any other vertebrates. I think this very important discovery is too little known because a fish’s supposed silence contributes to the mistaken assumption there is no communication. What is the technology that allows humans to “hear” fish? What sounds do fish make? How do fish use these sounds to communicate?
Having ears that evolved for processing vibrations in air and not water, we were deaf to most of the sounds fishes were making. It is only in the past century, as underwater sound-detecting technology improves, that we have come to realize how important sound is in fish communication and society. With their varied acoustic toolkit, fishes produce a veritable symphony of sounds, especially in the percussion section. Among the descriptors we have found for them are hums, whistles, thumps, stridulations, creaks, grunts, pops, croaks, pulses, drums, knocks, purrs, brrrs, clicks, moans, chirps, buzzes, growls, and snaps. So notable are the sounds of some fishes that we have named them accordingly: grunts, drums, trumpeters, croakers, sea robins, and grunters. Those herring farts I mentioned earlier appear to function acoust­ically as a means of communication among the school in the dark of night, when visual cues are ineffectual.

Fish have relationships and social lives, but many people probably only visualize a school of fish when thinking of fish living together. Can you explain the difference between a shoal and a school and some of the kinds of relationships fish have in each?
The fundamental social unit for fishes is the shoal or school. A shoal is a group of fishes who have gathered together in an interactive, social way. Shoaling fishes are aware of each other’s presence, and they seek to remain in the group, but they swim independently, and individuals may be facing in different directions at any given time. A school of fishes is a special case of shoaling, in which fishes swim in a more orderly fashion, each going the same speed and in the same direction and each spaced a fairly constant distance from the other. A shoal of fish is likely to be foraging, where­as a school—such as a million herring migrating east­ward along the South African coast—are schooling. Schools tend to be longer-lasting than shoals.

With over 33,000 known species, fishes have a wide range of social behaviors, most still unknown to us. Among those we have witnessed includes elaborate courtship and mating behaviors, parenting, mutual protection, interspecies cooperation, and virtue. The cleaner-client mutualism—in which so-called client fishes of over a hundred species receive parasite-removal services and spa-treatment massages from cleanerfishes—is one of the best studied and most complex of all known symbioses in nature. An example of interspecies referential communication, wherein groupers use a head-shaking gesture to invite known moray eels to go hunting with them on the reef—is a high-level cognitive behavior that is (so far) vanishingly rare in non-human animals.

“With over 33,000 known species, fishes have a wide range of social ­behaviors, most still unknown to us. Among those we have witnessed ­includes elaborate courtship and mating behaviors, parenting, mutual ­protection, interspecies cooperation, and virtue.”

Since fish within a species look so much alike to the human eye, can you talk about how fish tell each other apart?
Fishes are very visual, so visual cues are likely important in individual recognition among many species. It was recently discovered some fishes at least are subject to the “face-inversion effect,” which simply means that they struggle to recognize a familiar fish face when that face is presented upside-down. Humans also have the face-inversion effect. Another study, published in 2016 by a team of Ger­man researchers, confirmed what aquarium fish keepers have been claiming for generations: that fishes can recognize human faces!

The sense of smell is also important in fish commun­ication, and I suspect that some species may use it to recog­nize individuals.

Emotions are complex and, as you point out, easier to prove by anecdote than by science, but there has been documentation of fish experiencing emotions, including pleasure. What are some of your favorite stories of fish showing emotion?
It’s pretty clear that fishes can form attachments to one another, and they can become bonded to their human guardians, too. Several readers wrote to me about the games and affection they shared with individual pet fishes, and one can watch online videos of pet fishes who swim into the hand to receive gentle caresses and other pleasurable or playful interactions.

A woman in Seattle is greeted by her 9-year old puffer­fish when she comes home from work. They gaze into each other’s faces for minutes. “He usually outlasts me,” she says. Another correspondent described her games of “chase” with a blue discus fish. She would dart left and right next to the aquarium glass, and Jasper would follow her. Then, as they tired, she would cup her hands and immerse them in the tank. Once her hands were filled with water, Jasper would tilt onto his side and swim into the cup, where he would rest happily while his human gently stroked his side with her thumbs. No surprise that some fish-keepers mourn the loss of their finned “pets” no less intensely than we do the loss of a beloved cat or dog. And if you doubt that fishes can devel­op trust for a human, or that a gentle caress feels good to them, then you are not logging enough hours on YouTube.

This behavior is borne out by studies like one in which wild-caught surgeon fishes responded to stress by swimming up next to a moving wand to receive caresses, which caused their stress—measured as blood cortisol—to decline. Sta­tion­ary wands were ignored by these fishes, whose stress levels remained high.

One of my favorite quotes of yours is, “You don’t have to have fur or feathers to have personality; scales and fins will suffice.” Again, proving this is more anec­dotal, but you give several examples in your book. What is your experience with fish personality?
Once again, anecdotal observations show us that fishes are unique individuals. Some are more shy than others, some more bold, and some more creative and intel­ligent, for example. In a study published in 2017, British researchers subjected captive guppies to fearful situations, expecting the tiny fishes to show a “simple spectrum” of standard responses, with individuals reacting in basically the same way. They were surprised to discover that different guppies used different strategies to cope with the sudden appearance of a (model) predator, such as a heron or a larger fish. Some of the response strategies required more bravery than others. These behaviors were consistent over time within individuals, indicating that they reflect personality differences and not just random responses.

I have a friend who has a large elaborate koi pond. She loves her koi and spends a lot of time with them, naming them, noting their personality traits and indi­vid­ual coloring among the many fish. I asked her once if having the koi deterred her from eating fish at all. She said absolutely not, that she loved the taste of fish, and said the fish she ate was completely different from her pet fish. I know others with aquariums who think this way as well. People don’t have cats and then eat cats, so why is it easy to have this disconnect with fish?
We are like cats: We hate disruptions to our lives! Raised to eat fish, and taught that they are lesser creatures, cold-blooded, and incapable of thoughts or feelings (or, heaven forbid, pain!), our biases become entrenched. So much so that we can witness phenomena that touch us, yet remain blind to their deeper meaning. In the case of your friend, it is a failure to transfer empathy from one context to another. The koi swimming in the pond are compartment­alized from the salmon or tilapia who end up on her plate. In reality, they are, in all the import­ant ways—sentient, pain-avoiding, pleasure-seeking, possessed of a fierce will to live, etc.—moral equals.

Does the popularity and avail­ability of social media bring­ing issues into the main­stream give you hope that we will see change in the way we treat animals? What would be your advice for organiza­tions such as Animals Voice that use social media to bring about this change?
For those who labor toward a better world for animals, the pace of change can seem frustrating. But change is happening, and it is starting to accelerate. I take solace from humankind’s history of moral progress. Con­sider that only a few generations ago humans were mired in the atrocities of colonialism and institutionalized slavery, that women were denied voting rights, and that civil rights were widely accorded only to certain segments of society. Certainly, there is much work to be done in these and other moral domains, but moral progress ad­vances much, much faster than geological change, thank goodness! Today we are seeing unprecedented moral concern for animals. Hundreds of laws are being enacted to end some of the worst atrocities we inflict on animals. Veganism is enjoying a huge rise in popularity and cred­ibility.

“If you doubt that fishes can devel­op trust for a human, or that a gentle caress feels good to them, then you are not logging enough hours on YouTube.”

Investors the likes of Bill Gates and Richard Branson are pouring tens of millions of dollars into the development of alternative food technologies to replace the cruel, wasteful, and costly con­ven­tional meat from feeling animals. The government of China, a nation that now consumes nearly 40% of the world’s meat supply, has invested over $300 million in the develop­ment so-called “clean meat” produced in a lab and not from a living, breathing, feeling being.

There are many in the animal movement who scoff pessimis­tic­ally about these developments. I don’t. We need many doorways to progress, “many hands on many oars,” in the words of the animal rights philoso­pher Tom Regan. The best thing an individual can do to help fishes—indeed, any ani­mal—is to refrain from eating them.

Interview by Susan Barzallo, News and Associate Editor, The Animals Voice. To learn more about Jonathan Balcombe, visit his web site.