Zero is one of the most profound ideas in the history of mathematics. It took human civilisations thousands of years to conceive of nothing as a number. Honeybees, with brains containing fewer than one million neurons and no history of philosophy or arithmetic, appear to understand it naturally. That discovery shook the world of animal cognition and changed what scientists think intelligence means.
In 2018, a team of researchers at RMIT University in Melbourne published a study in the journal Science that sent ripples through the scientific community. They had trained honeybees to understand numerical quantities and then tested whether the bees could spontaneously place zero correctly below the number one on a numerical scale, without ever being trained to do so. The bees could. They were doing something that young human children, and many other animals tested in similar experiments, consistently struggle to do. The implications were extraordinary.
To appreciate how remarkable the bee discovery is, you need to understand why zero has always been conceptually hard. Most numbers refer to something you can point at. One apple. Three flowers. Seven bees. These are concrete quantities that map directly onto objects in the world. A child can grasp them by counting real things.
Zero is different. Zero refers to the absence of something. It requires the mind to treat nothing as something, to assign a numerical value to emptiness, and to place that emptiness in a logical relationship with other numbers. This is an abstract leap that requires what cognitive scientists call symbolic representation, the ability to let a symbol stand in for a concept that has no physical form.
The history of human mathematics reflects this difficulty. Ancient Egyptian and Babylonian number systems had no symbol for zero. The Romans had no zero and their numerical system was notoriously clumsy for complex calculation partly as a result. The concept of zero as a number that could be calculated with was independently developed in India around the 5th century CE and transmitted to the Arab world before reaching Europe. For most of recorded human history, zero was not understood as a number at all.
The study was designed with meticulous care. Researchers from RMIT University and the University of France used a two-phase approach. In the first phase, they trained bees to understand the concept of less than. In the second phase, they tested whether bees would spontaneously extend this understanding to include zero, which they had never been specifically trained to recognise as a quantity.
Bees were presented with two cards, each showing a different number of shapes ranging from one to five. One card always showed fewer shapes than the other. Bees that flew to the card with fewer shapes received a sugar reward. Bees that chose the card with more shapes received a bitter quinine solution. Over many trials, individual bees learned to consistently choose the smaller number.
Once bees reliably understood less than, researchers introduced a new card the bees had never seen before: a completely blank card showing no shapes at all, representing zero. This blank card was then paired with cards showing one, two, three, four, or five shapes. The question was: would a bee trained to choose fewer shapes treat the blank card as less than one?
The bees chose the blank card significantly more often than chance when paired with cards showing any number of shapes. They correctly placed nothing below one, two, three, four, and five on a quantity scale without being trained to do so. The closer the comparison number was to zero, the less certain the bees were, which mirrors the same pattern of hesitation seen in animals and humans near the boundary of a conceptual category.
Researchers carefully varied the size, shape, colour, and arrangement of the symbols on each card to ensure bees were responding to quantity and not to visual features like total ink coverage or overall brightness. The results held across all variations, confirming the bees were processing numerical quantity, not surface-level visual patterns.
We were not expecting the bees to do this. We thought they might choose zero as less than one, but the confidence and consistency with which they did it across different conditions was genuinely surprising. These are animals with a brain the size of a sesame seed.
Professor Adrian Dyer, RMIT University, 2018The zero finding did not arrive in isolation. It built on a decade of research establishing that honeybees have a surprisingly sophisticated numerical sense. Before the zero study, researchers had already demonstrated that bees could learn to count up to four objects reliably, could distinguish odd from even numbers in some contexts, and could use numerical information to navigate and communicate.
The bee brain achieves this with architecture radically different from vertebrate brains. Bees have no cortex, no limbic system, no amygdala. The structures associated with higher cognition in mammals are simply absent. Yet something in their neural organisation supports numerical reasoning powerful enough to handle one of the most conceptually demanding ideas in mathematics.
This forces a fundamental question in cognitive science: if such a small, structurally simple brain can represent the concept of nothing, what does that tell us about the nature of intelligence itself? The conventional assumption has been that complex cognition requires large, complex brains. Bees suggest this assumption needs revision.
Before 2018, the ability to understand zero as a numerical concept had been confirmed in only a small number of species. Each confirmation came as a scientific surprise because it required experimental evidence that an animal was not just ignoring absence or responding to visual simplicity, but was actively placing emptiness on a number line and using it in comparative judgements.
Trained chimps demonstrated zero comprehension in the 1980s, placing empty sets below sets of one in numerical tasks. Considered less surprising given their genetic proximity to humans.
Alex, the famous research parrot studied by Dr Irene Pepperberg, produced the label none when shown an empty tray, suggesting spontaneous zero understanding.
Crows were shown to spontaneously place empty sets at the low end of a numerical scale in 2015, before the bee study and considered a landmark finding in corvid cognition.
Elephants show some evidence of zero-like behaviour in certain foraging contexts but have not been confirmed to place zero on a number line in controlled laboratory conditions.
Recent studies suggest archerfish may respond to empty sets differently from small sets, hinting at proto-zero understanding, but evidence remains preliminary and contested.
Confirmed in 2018 at RMIT. The most shocking addition to the list given the tiny brain involved. Bees spontaneously placed blank cards below cards showing one shape, without specific training for this task.
A reasonable question after all this is: why would a bee need the concept of zero in the first place? What ecological pressure could have driven the evolution of this capacity in an insect whose apparent concerns are flowers, hive temperature, and colony survival?
Researchers have proposed several possibilities. Foraging decisions require bees to compare quantities continuously. A bee assessing two flowers must judge which has more nectar remaining. A flower with nothing left, effectively a zero-value target, must be distinguishable from a flower with a small amount remaining to prevent wasted foraging time. The ability to treat nothing as a distinct quantity rather than merely an absence might make foraging decisions more efficient.
Another possibility, and one that cognitive scientists find particularly interesting, is that numerical reasoning in bees may be a byproduct of other cognitive adaptations rather than a directly selected trait. The same neural mechanisms that allow bees to count landmarks, assess flower quality, and communicate precise distances may incidentally generate zero comprehension as an emergent property. Intelligence, in other words, may be more about the architecture of information processing than about specific evolved traits.
The bee zero study sits within a broader revolution in animal cognition research that has been unfolding for several decades. Scientists used to believe that higher cognitive functions were the exclusive province of vertebrates with large brains. Tool use, planning, numerical reasoning, and abstract thought were considered markers of intelligence that separated humans and a small number of close relatives from the rest of the animal kingdom.
This view has been dismantled systematically by research. Crows make and use tools. Octopuses solve multi-step problems. Fish recognise individual faces. And honeybees understand zero. The pattern suggests that complex cognition emerges in many different forms across many different architectures, driven by ecological pressure toward efficient information processing regardless of the substrate it runs on.
For bees specifically, the findings have practical implications that go beyond pure science. Understanding how bee brains process numerical information could inspire new approaches to artificial intelligence. A system that achieves sophisticated reasoning with one million neurons is doing something worth studying closely. The efficiency of bee cognition, the ability to achieve so much with so little, is precisely the quality that AI researchers most want to replicate in low-power computing systems.
Several research groups are now studying the neural architecture of bee brains specifically to understand how they achieve efficient numerical processing. The mushroom bodies of the bee brain, structures that handle learning and memory, have been modelled computationally and used to develop algorithms that match or exceed human-designed approaches in certain navigation and classification tasks. A creature that can handle the concept of zero with a brain smaller than a pinhead is teaching computer scientists things that decades of theoretical work had not revealed.
It is worth pausing here to connect these extraordinary cognitive findings back to the physical object at the centre of everything: the honeycomb. The bees who participated in the zero experiments were not laboratory curiosities. They were the same species of bee that builds the hexagonal wax structures that Tru-CocoB harvests and delivers as raw honeycomb.
Every piece of raw honeycomb is built by bees that can count, that can learn abstract rules, that can communicate complex spatial information through dance, and that appear to understand the numerical concept of nothing. The honeycomb they build is not a simple reflex product. It is the output of a colony intelligence that has no single seat, no central brain, no executive decision-maker, but that collectively achieves engineering precision, resource management, and adaptive behaviour that continues to astound researchers who have spent careers studying it.
When you eat raw honeycomb from Tru-CocoB, you are eating something produced by one of the most cognitively sophisticated creatures on earth, scaled to its size. That context does not change the taste, but it changes what the taste means.
Human mathematicians took thousands of years and multiple independent civilisations to fully grasp zero as a number. Honeybees appear to understand it as a natural extension of the quantity-comparison abilities they evolved to survive. Whether this constitutes true abstract reasoning or a functional approximation that mimics it is still debated by scientists. What is not debated is the result: a creature with one million neurons and no mathematical education consistently placed nothing below one, spontaneously and correctly, in rigorously controlled experiments. The bee did not know it was making history. It was just doing what bees do. As it turns out, what bees do is considerably more than most of us ever imagined. The honeycomb on your plate was built by an intelligence that understood zero before most of human civilisation did.
