Bees Have Brains Smaller Than a Sesame Seed — and They Can Still Do Math

Imagine being handed a math quiz where you had to identify which group of shapes had more objects — without using words, a pencil, or even a number line. Now imagine doing it with a brain the size of a sesame seed. That is exactly what honeybees appear to be pulling off, according to a new study from Monash University in Australia. Researchers there have confirmed something that has been debated among scientists for decades: honeybees do not just react to what things look like — they actually understand numbers in a meaningful, abstract way.

Honeybees, known scientifically as Apis mellifera, have brains that weigh less than one milligram and contain fewer than one million neurons. Neurons are the specialized cells in a brain that send and receive signals, kind of like tiny biological wires that carry information. For comparison, a human brain has roughly 86 billion neurons. Despite having only a tiny fraction of that number, bees have already surprised researchers in previous studies by showing an understanding of addition, subtraction, and even the concept of zero. Zero is considered one of the more advanced mathematical ideas because it represents the absence of something, which is much harder to grasp than simply counting objects that are right in front of you.

For this new study, the research team, led by scientist Scarlett Howard, designed a careful experiment using reward-based learning. They showed bees surfaces covered with different numbers of black shapes — varying in type and quantity — and also included a completely blank surface to represent zero. When bees chose the correct numerical answer, they received a sweet reward, like sugar water. This method, known as incentive-based training, is widely used in animal cognition research because it allows animals to demonstrate understanding without needing to speak or write anything down. Cognition, by the way, is the scientific term for the mental processes involved in thinking, learning, and understanding.

The key question the scientists were trying to answer was whether bees were actually reasoning about numbers or just picking up on visual shortcuts — like always choosing the busier-looking image because it had more stuff on it. These shortcuts are called low-level perceptual cues, and some skeptics believed that was all the bees were doing. However, the results, published in the journal Proceedings of the Royal Society B: Biological Sciences, showed clearly that the bees were doing something more sophisticated. They were engaging in abstract numerical reasoning, meaning they understood the concept of a number itself, not just reacting to what the image looked like at first glance.

Collaborating neuroscientist Mirko Zanon from the University of Trento pointed out that the biology of the bee — how its brain is actually built — supports this conclusion in ways that previous critics had not fully considered. Outside a laboratory, this number sense likely serves a very practical purpose. Scientists believe bees may count flower petals to determine which plants contain the most nectar, helping them remember and return to the best food sources. This is an impressive real-world skill that directly supports their role as pollinators, the crucial ecological job of carrying pollen between plants so they can reproduce and produce fruits and seeds.

The research also has exciting implications beyond just understanding bees. Because bees can perform complex reasoning with so few neurons, their brains may offer a useful model for improving artificial intelligence. Right now, many AI systems require enormous amounts of computing power to do relatively simple tasks. The bee's example suggests that smarter, more efficient designs might be possible — proving that sometimes less really is more. Most importantly, the study is a reminder that intelligence is not a single thing owned by humans or large-brained animals. It exists across the natural world in forms we are only beginning to understand.

Source: Popular Science