Crows Just Earned Another Proof of Their Remarkable Intelligence. A New Study Showed That These Birds Are Capable of Identifying Geometric Shapes, Such as Triangles, Circles, and Squares, with a High Degree of Accuracy
A study conducted in Germany revealed that crows have a rare ability: to recognize regular geometric patterns and identify outliers in sets of shapes. The discovery drew attention because it shows that these animals have a visual intuition similar to that of humans.
Natural Geometric Sensitivity
Researchers from the University of Tübingen trained two male hooded crows, aged 10 and 11, to detect different shapes among sets of figures displayed on a screen. The crows needed to peck at the figure considered “intruder,” that is, the one that did not match the others.
The goal was to understand whether these animals would be able to perceive geometric irregularities without ever having been directly trained for this task.
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Until that time, the crows had never been exposed to this specific type of challenge with quadrilaterals. This ensured that the tests evaluated innate perceptions, not learned behaviors.
Tests with Different Levels of Difficulty
The figures presented included squares, rhombuses, isosceles trapezoids, hinges, and irregular quadrilaterals. All appeared with variations of rotation and size. The idea was to observe how the crows would react to more regular shapes and others that were more eccentric.
The results were clear: the more regular the shapes were—with equal sides or 90-degree angles—the more easily the crows could detect the odd figure. Shapes like squares and rectangles resulted in better performance in the tests.
When exposed to less familiar shapes, such as rhombuses or quadrilaterals with varied angles, the crows showed greater difficulty. But even in those cases, they managed to identify patterns, indicating an advanced visual capability.
Similarity with Humans
Physiologist Andreas Nieder, who led the study, highlighted the similarities between the behavior of crows and that of humans. Like us, they also find it more difficult to perceive geometric patterns in asymmetrical shapes.
Additionally, the team used, in part of the tests, simpler figures like stars and moons—already known to the crows—to maintain the animals’ interest and avoid frustration with more complex challenges.
Evolutive Foundation of Geometry
The discovery goes beyond a simple curiosity about animal intelligence. According to researchers, the ability to identify regularity in shapes may have been essential for the survival of various species. In the case of birds, this may be linked to spatial orientation and navigation in natural environments.
“Birds use spatial regularities, for example, to orient themselves and navigate in larger environments“, Nieder explained. “This gives them a survival advantage.”
Innate and Untaught Ability
The main point of the research was to show that these crows did not need to learn the task. They already possessed, naturally, the ability to perceive geometric properties in flat figures. This visual intuition may have deep biological roots, shared by different species throughout evolution.
“This basic intuition of crows, their ability to understand geometric properties in two-dimensional shapes, exemplifies how the basic understanding of magnitudes and geometry is rooted in biological evolution”, Nieder stated.
Recognized Publication
The results of the study were published in the journal Science Advances. This is the first time that this type of geometric visual perception has been demonstrated in a non-human species. This expands the understanding of how visual cognition has evolved and may be more widespread among animals than previously thought.
The crows demonstrated this ability without any specific training to detect intruder quadrilaterals. This reinforces the idea that certain visual principles, such as the regularity of shapes, are perceived instinctively, even without teaching or language.
The research was published in Science Advances.

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