Even before children are formally taught how to count, they develop a mental structure for organizing things. In most of the world, children start organizing quantities from left to right. But in Arabic countries, where writing goes from right to left, studies have shown that children order quantities from right to left, even though they haven’t yet picked up the script.

While there is still some debate as to whether this skill is influenced by biology or culture (or both), researchers are increasingly looking at how animals count.

“The subject is still being debated between those who think the mental number line has an innate character and those who say it is cultural,” said Martin Giurfa, a professor at the Research Center on Animal Cognition at Paul Sabatier University in Toulouse, France.

Now, more evidence in this debate comes from an unlikely source: bees.

Studies have shown that some primates count (or rather, organize quantities) from left to right. It’s also been found in fish, rats, birds, dogs, and even ants. But there hasn’t been any research on bees in this area.

Research is increasingly showing that bees are smarter and more complex than we thought. For instance, research has shown that bees can and often do play, exhibit striking cognitive abilities, and even have a grasp of numerical concepts. It’s already been shown that they can count to at least 5, So Giurfa and colleagues set up an experiment to see how bees count.

They had the bees fly into a wooden box that was split into separate compartments. Sugar-water was used to entice the bees to select a number affixed to the middle of the second compartment. Numbers were represented as shapes (circles, triangles, or squares) and remained unchanged for individual bees, but were assigned randomly across different bees as 1, 3, or 5. Then, once the bees were trained to fly towards their set number, the researchers put another number on both sides of the compartment, left the middle blank and removed the reward. This was the test.

They then watched to see which way the bees went.

So where did the bees fly to? It depends on what they were trained with. If the number they were tested with is the same number they were trained on, they showed no preference left or right. But if they had to choose, they chose as if they were counting from left to right.

“It depends on your reference number,” Giurfa tells ScienceNews. Of the bees trained on “one,” 72 percent flew to the “three” panel to the right, but of the bees trained on “five,” 73 percent went to the “three” panel to the left. “That’s exactly the concept of the mental number line,” Giurfa says. “You align numbers based on your reference.”

While not everyone is yet convinced, this makes a pretty compelling case that bees really do count left to right. The researchers interpret this as a biological cause that originates somewhere in our distant evolutionary tree — in order to incorporate creatures like bees, fish, and mammals, it would have to be a distant ancestor indeed.

But if the way we count is biological, why don’t all people count like that? The answer, the researchers suspect (although they did not investigate this) is that it is a case of culture overriding biology. In other words, even if the drive to count left to right is there, culture can modify or even reverse it. The effects of this process, if this is really the case, are not at all understood.

The study was published in PNAS.