Fish have feelings too
Under-the-sea society is much more complex than we imagine
By April 2017
It is hot on the boat ramp at Woollamia, near Jervis Bay on New South Wales’ South Coast. The water shimmers beneath the crowding mangroves, and the air is glassy with the sound of cicadas. Despite the beating sun, Joni Pini-Fitzsimmons, a masters student from Sydney’s Macquarie University, wears only a cap for protection as she stands staring into the shallows.
Pini-Fitzsimmons is here to observe the short-tail stingrays that gather in the inlet. Although they are usually solitary, the rays at Woollamia have begun to develop social behaviours and hierarchies as a response to competition for the refuse that drains from a pipe into the inlet from the fish-cleaning table behind the ramp.
Her research suggests – perhaps predictably – that the rays’ hierarchies are largely determined by size, with bigger specimens tending to dominate. (Short-tail stingrays often span more than 2 metres and can weigh up to 350 kilograms.) But her findings also reveal a surprising degree of variation in behaviours, with each of the 17 rays that inhabit the inlet – all females – seemingly possessing individual quirks, habits and personalities.
This observation, as Pini-Fitzsimmons freely admits, is partly projection. But as the first ray arrives, gliding through the inlet like the stealth plane it so resembles, it doesn’t seem entirely unreasonable. The massive ray, named Raylene by Pini-Fitzsimmons, is immediately recognisable from the semi-circular scar behind her eyes, the legacy of a fisherman’s hook. And, as Raylene sweeps in a long figure eight from the deeper water into the shallows by the pipe and out again, it is difficult not to be aware you are watching a creature with its own purpose and identity.
The idea that stingrays – or indeed fish in general – might have individual identities is not one that human beings find easy to accommodate. When we think of them – which is not often – it is usually as indistinguishable, interchangeable, slimy automatons with only the most primitive kind of awareness. It is an attitude embedded in our very language, the way the simultaneous singular and plural of the word “fish” elides their particularity.
A growing body of evidence suggests quite the opposite: that fish possess not just considerable intelligence but also identities, feelings and even the capacity for abstract thought.
In a way this shouldn’t be surprising, as fish form one of the most ancient groups of organisms on Earth. They are supremely adapted to their environments, and are more diverse than mammals or birds (to date more than 33,000 species of fish have been identified, outnumbering all other vertebrates combined), so to speak about them as an undifferentiated mass is as absurd as lumping together a sloth and a dolphin, or a chicken and a crow. So varied is the group that osteichthyes (bony fish) are genetically closer to human beings than they are to chondrichthyes (cartilaginous fish, such as rays, sharks, skates and sawfish).
One of the researchers exploring this new world of fish cognition is Culum Brown, Pini-Fitzsimmons’ supervisor at Macquarie University. His own research began with a study of rainbowfish, a small, colourful species native to Australian and New Guinean creeks and rivers.
Watch rainbowfish in a tank and, at least at first, it is difficult to imagine them as creatures possessed of much inner life. With their large eyes and sudden, twitchy motion they seem nervous, flighty. Yet watch a little longer and that twitchiness begins to look more like tensed caution, their rapid movements indicating not randomness but intention.
As Brown’s research revealed, not only do rainbowfish recognise each other, preferring to shoal with familiar individuals than strangers, they also have social hierarchies and lead complex social lives. They are also capable of learning to evade traps, and, having done so, of teaching these techniques to their shoalmates. Even more strikingly, rainbowfish will learn to associate a signal with food twice as fast as rats can.
The social and cognitive skills of the rainbowfish pale in comparison to those of the Great Barrier Reef’s cleaner wrasse. These small fish maintain “cleaning stations”, at which other fish stop and have dead skin and parasites removed by the wrasse’s nimble mouths.
The stations are popular, often attracting upwards of a hundred “clients”, and wrasse are capable of remembering and recognising each individual. Yet while they are skilled at their job the wrasse are not angels. Given the chance they will nip their unwary customers, stealing patches of flesh along with the parasites and dead skin. Unsurprisingly, the fish they bite in this fashion often respond badly, so wrasse choose their victims carefully, avoiding aggressive predators.
What’s more, wrasse seem to understand the impact a reputation for nipping will have on their popularity, not only nipping less if they know they’re being observed but also chasing after victims who respond badly and attempting to mollify them by rubbing their backs with their pelvic fins, a behaviour fish find calming.
This sort of Machiavellian behaviour seems to imply a capacity to attribute mental states to others, or what is called “theory of mind”. And while this concept has its detractors – some scientists argue that it fails to recognise the various and often fluid ways animals think – theory of mind is still a capability hitherto only observed in some primates, birds and dolphins.
Nor are the capabilities of fish exclusively social. Wrasse and tusk fish have been observed striking shellfish against rocks to crack them open, behaviour strikingly reminiscent of that found in crows and other birds. Cod held in an aquaculture facility were recently found to have taken to stealing food after learning that the tags on their fins could be employed to trigger a feeding device. One recent study even suggested that manta rays – which have the largest brains of all fish – are capable of recognising themselves in a mirror, a crucial test of self-awareness previously only seen in a handful of mammals and birds.
In recent years we have become increasingly aware of the cognitive sophistication of other animals: our assumption that they are dumb brutes giving way to evidence of abstract reasoning in parrots, the use of signature whistles as names among dolphins, displays of grief in elephants, and devious politicking among chimpanzees. Yet the notion that fish might display similar abilities remains difficult to assimilate.
The reasons for this are no doubt complex. At a very basic level, human interactions with fish are extremely limited, as are the opportunities to observe them in their natural environment. But there is little doubt the problem is also about a failure of imagination: their anonymous, expressionless faces and physical differences render them deeply “other”.
Another reason, however, may be that the concept is simply too confronting. If we were to accept that fish not only think but feel and suffer it would require us to consider the ways in which they are caught. Not coincidentally, Pini-Fitzsimmons has stopped eating fish since she began studying them, and while Brown has not, preferring to emphasise the importance of humane fishing practices, he is increasingly conflicted about this choice.
But perhaps it is time we made that imaginative leap. For as Raylene glides away into the deeper water her silent purpose underlines how little we understand of her and her world, and how transformative it might be were we to try.