Key Takeaway:
Research shows that some animals form surprising partnerships, challenging traditional views on how intelligence evolves in the animal kingdom. For example, Octavia and Finn, a day octopus and coral trout, work as a team, each bringing unique skills to the hunt. Other species have also developed remarkable partnerships, such as the greater honeyguide bird and humans, which engage in cross-species conversations. In the underwater world, cleaner wrasse remove parasites from larger “client” fish, but these relationships involve strategic decision-making. The most captivating example of marine collaboration is between octopuses and fish, which are solitary animals but show social sophistication. A blend of ecological and cognitive factors likely underpin these partnerships, with dietary overlap, cognitive abilities, habitat complexity, and timing playing crucial roles. This idea broadens the way scientists think about social intelligence, showing that the capacity to collaborate can arise wherever there’s something to be gained from working together.
In the ever-shifting natural world, competition has long been cast as the dominant theme. Predator and prey. Survival of the fittest. Yet behind this familiar narrative lies a subtler, more collaborative story—one in which species reach across boundaries to form surprising partnerships. These unexpected alliances are not only fascinating, but they’re also challenging long-held assumptions about the roots of intelligence and cooperation.
Among the most intriguing examples are marine pairings that seem more like scenes from a science fiction epic than reality. On tropical coral reefs, recent research has shed light on a remarkable hunting duo: a day octopus and a coral trout. What appears at first to be a one-sided game of opportunism—fish trailing an octopus in hopes of snatching flushed prey—has turned out to be far more complex. It’s not just shadowing; it’s strategy.
These octopuses and their piscine companions don’t simply coexist during the hunt. They collaborate. The trout performs body gestures—hovering vertically near crevices to flag hidden prey—while the octopus responds with a swift, precise reach to flush it out. And when a partner isn’t contributing? The octopus might deliver a swift “punch” to bring them in line. It’s a surprisingly coordinated exchange between two creatures with vastly different anatomies, and it suggests a level of social nuance rarely associated with solitary animals like the octopus.
This kind of interspecies cooperation is not limited to the sea. On land, birds and mammals are also building surprising bridges. The greater honeyguide, for instance, has learned to lead human honey-hunters to beehives using calls and flight patterns. Once the humans break open the hives and gather the honey, the bird returns to feast on the leftover wax and larvae—its preferred delicacy. Such a partnership has been shaped over generations, an evolutionary dance built on mutual benefit and trust.
Not all alliances are so harmonious. In the African savannah, the fork-tailed drongo keeps a lookout for meerkats, warning them of nearby predators. But the drongo is a trickster as well: occasionally issuing false alarms to clear the area and snatch abandoned prey. This blend of cooperation and deception reflects the delicate balance between self-interest and mutual gain.
In the underwater realm, these social dynamics take on another dimension. Cleaner wrasse operate what are effectively fish “spa” services. Larger reef fish line up patiently at cleaning stations to have parasites nibbled off their skin. But even here, trust can be tested—cleaner wrasse sometimes cheat, biting into protective mucus rather than parasites, prompting clients to abruptly end the session. These interactions aren’t random—they reflect strategic decisions made by both cleaner and client, hinting at a kind of social negotiation.
What ties all these examples together is the growing recognition that collaboration isn’t just a human—or even a mammalian—trait. Scientists are now beginning to see that intelligence can be shaped not just by intra-species relationships but by the challenges and opportunities of cross-species interaction.
A recent breakthrough came when researchers, combining camera data and behavioral analysis, observed octopuses and coral trout cooperating in ways once thought implausible. These findings, published in 2024, have opened new windows into the cognitive landscapes of these creatures. By studying motion patterns and responses, scientists could piece together how these animals communicate, coordinate, and adjust to one another—sometimes in real time.
Why do these partnerships arise? The answer lies in a cocktail of ecological and cognitive ingredients. Species that share similar prey are more likely to benefit from cooperative foraging. But collaboration also demands a capacity for behavioural flexibility—adjusting one’s actions based on a partner’s cues—and a degree of self-restraint. The fish must wait for the octopus to act; the octopus must interpret the fish’s signals. All of this plays out in visually complex environments like coral reefs, where communication relies heavily on sight. It helps, too, that both are active during daylight hours, ensuring their cues don’t get lost in the dark.
Beyond just the practical benefits, these interactions suggest deeper cognitive abilities. Some researchers propose that animals engaging in such coordinated behavior may be using skills related to “theory of mind”—the ability to perceive another’s perspective or intention. While this idea remains controversial, especially in non-social animals like octopuses, the fact that they can read and respond to another species’ cues is compelling.
Such insights challenge the long-standing notion that intelligence is tied solely to social living within a species. Until recently, the dominant view was that complex cognition evolved primarily in species with tight-knit social groups—primates, elephants, dolphins, or certain birds. But partnerships like those between octopuses and fish suggest intelligence may also be forged in the fires of interspecies collaboration.
A new wave of research is taking these ideas even further. One initiative, funded by the National Geographic Society, is developing robotic fish designed to engage with day octopuses. By controlling one side of the interaction, researchers hope to decode the subtle communication cues exchanged during joint hunts. This intersection of biology and robotics might offer answers to questions that have long eluded scientists: What does the octopus perceive when its partner fish signals? How does it decide to respond—or retaliate?
Ultimately, these revelations carry broader implications for how intelligence is understood, defined, and studied. They suggest that mental sophistication might not only emerge within tightly knit communities, but also through necessity—when the environment demands cooperation, even between the most unlikely of allies.
As our understanding of animal cognition deepens, it becomes clear that no species evolves in isolation. Whether in coral reefs, deserts, or forests, collaboration can be a powerful force, one that pushes the boundaries of intelligence—and rewrites the rules of survival.
