At SciTechDaily, the Max Planck Institute of Animal Behavior tells us that “Fish in the wild can tell humans apart! A study found that seabream recognize individual divers, following those who feed them while ignoring others.” (The exclamation point is theirs.)

For years, scientific divers at a Mediterranean research station noticed a curious problem — local fish would follow them and steal food meant for experiments. Even more intriguing, the fish seemed to recognize and target specific divers who had fed them before, while ignoring others. To test whether wild fish could truly distinguish between individual humans, researchers from the Max Planck Institute of Animal Behavior (MPI-AB) in Germany conducted a series of experiments. By varying their diving gear, they discovered that fish in the wild can indeed tell people apart using visual cues…

Scientists set out to answer a question that had never been tested in wild fish: can they tell people apart? While some studies have shown that certain captive fish, like archerfish, can recognize human faces in controlled lab settings, there was little evidence that wild fish could do the same.

“But nobody has ever asked whether wild fish have the capacity, or indeed motivation, to recognize us when we enter their underwater world,” explains Maëlan Tomasek, a doctoral student at MPI-AB and the University of Clermont Auvergne, France.

“Scientists Discover Wild Fish Can Recognize and Follow Specific Humans,” February 18, 2025

The wild fish told the divers apart by their diving gear. From the open access paper:

Many animal species have been shown to discriminate between individual humans in captive settings and may use a variety of cues to do so.Empirical evidence remains scarce for animals in the wild, however, particularly in aquatic contexts. For the first time, we investigated discrimination of individual humans by fish in the wild. We first trained two species of fish, saddled sea bream Oblada melanura and black sea bream Spondyliosoma cantharus, to follow a human diver to obtain a food reward.We then investigated whether they could discriminate between two human divers and follow the correct one in an operant-conditioning paradigm. Weshow that both species were able to quickly learn to discriminate between the two divers when they wore different diving gear. However, they showed no preference when both divers wore identical gear, suggestingthat discrimination is based predominantly on visual cues from the dive gear. We discuss the implications of these results for ethical considerations and research practices.

Wild fish use visual cues to recognize individual divers” by Maëlan Tomasek, Katinka Soller and Alex Jordan, 1 February 2025, Biology Letters. DOI: 10.1098/rsbl.2024.0558

But what did the experiment actually demonstrate?

Fish are not very smart compared to, say, crows. But why should we be surprised that the wild fish would learn to detect a visual signal that means that food is available? Isn’t picking up signals of various kinds — sight, sound, smell — how animal life forms usually detect food?

We needn’t be surprised that fish learned to detect a new signal (different colored flippers) either. If life forms didn’t know how, in principle, to detect new signs of food, their lineages would have died out ages ago. Environments are constantly changing.

The fact that captive fish can “recognize human faces in controlled lab settings” also shouldn’t be a surprise if the humans have any impact on their environment.

This finding useful, of course, in understanding fish minds. But we should place it in a context. For example, the researchers write,

The fact that wild bream can discriminate between divers adds scientific evidence to the numerous accounts suggesting differentiated relationships between fish and specific humans [17]. Individual discrimination is required for specific bonds between humans and non-human animals, and our results suggest that this possibility should also be considered in taxa such as fish. Indeed, this ‘inevitable bond’ also has implications for research, influencing for instance how animals will react to different experimenters

Bonds? Are they kidding? The lab fish do not need to know that the faces are part of human beings. Or even that we are human beings. Or even that emotional bonds of some kind are a “thing.”

All the fish need to know is what sort of change to expect from the presence of a human, whether a lab technician or a diver. If that change is a food reward, well, follow the rewarding face or the winning flipper, right?

Of course, the fish may turn out to be smarter than we used to think, as the octopus and the lobster did. But we should be cautious about importing human assumptions about what the level of intelligence demanded by the perennial quest for food means.

Because the complexity of animal intelligence is a new idea to take into account, there is a risk of assuming far too much from far too little. At Issues, for example, science write Brandon Keim writes,

Today the scientific conversation has moved well beyond whether or not animals are intelligent. The most interesting and adventurous questions are now: What sort of intelligences might yet be found? How can welfare be assessed in species very different from humans? What is the interplay between instinct and reflection? What sorts of meanings do places hold for animals? How do animals understand death? Can animals have a sense of beauty? How does cognition shape ecology?

“When That Chickadee Is No Longer “A Machine With Feathers”,” Spring 2025

The obvious risk here is to lurch from ignoring the clever ways life forms learn to find food and protect themselves to a relentless attempt to find human mental and emotional qualities in all sorts of life forms that don’t have or need them. Efforts to protect environments or alleviate suffering could easily be hijacked by a need to see ourselves in everything.