Japanese macaques have drawn with chalk and stones, resembling the playful creativity of children.

Humans as a species learned to use tools, according to modern data, more than three million years ago. This skill is regarded as a leap in the cognitive abilities of our ancestors, and technology has continued to evolve based on various tasks. A more complex, yet equally important question is: when did humans learn to draw? The earliest evidence of cave paintings dates back 44,000 years, while simpler marks (notches and lines on stones) are even older.

But how did humans master drawing? Researchers are seeking answers from two perspectives: archaeologists look into the past, while, for example, anthropologists observe the contemporary behaviors of our closest relatives, primates. There are various confirmations of the high cognitive abilities of monkeys — for instance, recently Naked Science reported that extensive observations helped primatologists find individual differences in nut-cracking among chimpanzees (some individuals did it twice as fast as others).

Ethologist Cédric Sueur from the University of Strasbourg in France noted the manipulations of Japanese macaques (Macaca fuscata) with stones and chalk. A year ago — from January 16 to 28, 2024 — he studied the behavior of nearly 200 monkeys, as they rolled large and small stones on the ground. Then, Cédric provided the macaques with white chalk: he left it near large stones that were too heavy to move, observed how the primates used it, and then photographed the resulting drawings. He shared his thoughts in a recent article published in the journal Primates.

For almost two weeks from 08:30 to 17:00, Cédric recorded how 189 macaques from the park on Sedo Island moved stones across the ground, leaving various lines. The caretakers wiped them away twice a day, so the monkeys constantly had a "canvas" to work with. The ethologist noticed that the macaques were most active in making marks under two conditions: when there were many tourists around who willingly fed the animals, and when the weather was sunny and warm, and the ground was dry.

The macaques employed three strategies: they pushed boulders in front of them, leaving long trails; sat and rolled them; and played with smaller stones — the latter two approaches created small tracks. Cédric recorded the length and width of the lines and counted instances where the tracks intersected or ran parallel to each other.

The second set of data — the manipulations with chalk — was collected over four days, from January 21 to 25. The macaques drew with white chalk on stones, bit, ate, and put it in their mouths, rolled it, sniffed it, broke the chalk, and did many other activities — the ethologist aimed to document all actions. On average, the monkeys spent about half a minute with the chalk (the longest being 114 seconds). In half of the cases, the macaques rubbed the chalk on stones, a third of the time they rubbed it in their paws or broke it, and less frequently did they eat or move with it. Interestingly, the primates managed to draw on 43 surfaces — from stones and concrete blocks to roots and boards.

Some of the lines on the ground that the primates drew with stones reached over two meters in length, and the average number of parallel lines, according to the researcher’s calculations, was 13.85 ± 11.35. Moreover, there were more of them when the macaques played with small stones — after rolling on the ground, a fan pattern was left behind.

However, a common characteristic across all observations was the age of the macaques rolling stones or playing with chalk: almost all were young. Cédric noted only one adult female and one adult male engaging with the chalk, and a few adult females dragging boulders across the ground.

Although the author of the scientific work emphasized that the nature of the drawings seemed spontaneous overall, he described the rubbing of chalk on various surfaces as purposeful. The macaques might have been trying to outline an object, meaning they intended to leave a mark within clear geometric boundaries — according to the ethologist, this outlining could have emerged prior to the conception and understanding of drawing.

“This may indicate a preliminary stage in the evolutionary emergence of the intention to draw, where leaving marks gradually becomes associated with meanings or functions beyond the immediate action. The act of marking with chalk appears to be a self-rewarding activity for the macaques. Such behavior highlights that the activity can bring satisfaction in itself, regardless of its outcome, similar to what is observed in the early stages of children's learning to draw,” Sueur reflected in his article.

While the marks left by the stones on the ground may not closely resemble "drawing" (the symbolism behind the chaotic lines was not apparent), they may still help to understand the cognitive mechanisms that once compelled humans to draw. At the very least, the ethologist discerned intention in these manipulations, and the actions of the macaques resembled exploration — perhaps they were curious about how a boulder interacted with its surroundings.