Scientists have discovered that crows remember faces and not only recognize human faces but can hold grudges against those who wrong them—even up to 17 years later.
This remarkable ability challenges our understanding of animal intelligence and highlights the complex social lives of these birds.
Crows are often seen as ordinary black birds cawing from treetops, but they are anything but ordinary. Recent research has revealed that crows possess incredible memories, can use tools, solve complex problems, and even understand the concept of numbers. Perhaps most astonishing is their ability to recognize human faces and remember how they were treated by specific individuals for many years. This newfound knowledge is changing how scientists perceive intelligence in the animal kingdom and prompting us to reconsider our relationship with these fascinating creatures.
A Memory Like No Other
John Marzluff, a professor of wildlife science at the University of Washington, conducted a groundbreaking experiment that spanned over 16 years. He and his team wanted to understand how well crows could remember human faces. They used masks—specifically a “caveman” mask—to ensure that the crows were reacting to the face itself and not other cues.
During the initial phase of the study, researchers wearing the caveman mask captured and banded several crows on the Seattle campus. This was an unpleasant experience for the birds, and they associated the masked face with a negative event. Over the years, Marzluff and his students periodically wore the same mask while walking around the campus to observe the crows’ reactions.
Astonishingly, each time the masked person appeared, the crows would react aggressively. They recognized the mask, sounded alarm calls, and even mobbed the individual, swooping down to scare them away. This behavior continued for over a decade and a half. “Recognizing whether people are friend or foe is crucial for crows to survive in an urban environment,” Marzluff explained.
What’s even more remarkable is that the original crows involved in the first capture had long since passed away. The newer generations of crows still recognized the mask and responded with hostility. This suggests that crows can pass information about dangerous individuals to their offspring or other members of their flock.
Passing Down the Grudge
The fact that crows remember a threatening human face for at least 16 years—and potentially up to 17 years or more—is evidence of their incredible memory and social learning abilities. According to Marzluff’s observations, the crows not only remember but also teach others about the dangers associated with certain humans. “It just doesn’t pay to keep scolding this guy,” Marzluff noted, hoping that eventually, the crows would realize that the masked human was no longer a threat.
This behavior indicates a complex social structure where knowledge is shared among individuals. It also shows that crows can hold grudges for a very long time, affecting how they interact with humans who have wronged them.
Tool Use and Problem-Solving
Beyond holding grudges, crows have demonstrated exceptional problem-solving skills. New Caledonian crows are famous for making their own tools in the wild. They fashion hooks from sticks and even bend wires to extract food from hard-to-reach places. This ability to create and use tools was once thought to be unique to humans and some primates.
In laboratory settings, researchers like Loma Pendergraft from the University of Washington have trained American crows to use tools in experiments inspired by Aesop’s Fables. In one study, crows had to drop pebbles into a container of water to raise the water level and retrieve a floating treat. While not all crows succeeded, those that did showed a significant shift in brain activity, indicating they had developed a new skill.
“Those four birds that had fully mastered the task showed a complete shift in brain activity compared to their less-capable peers,” Pendergraft observed. This shift suggests that crows can learn and adapt, using muscle memory once they have mastered a new tool or technique.
Understanding Other Minds
Crows also exhibit what scientists call “theory of mind,” the ability to understand that other beings have their own thoughts and intentions. This is a rare trait in the animal kingdom. Crows often hide food in secret caches, remembering hundreds of locations. If they notice another crow watching, they may pretend to hide the food but actually keep it hidden in their beak, only to stash it elsewhere later.
“Once they do that, they realize, ‘Oh, wait a minute. If I can steal his food, then he can steal my food,'” Pendergraft explained. This shows that crows are not just acting on instinct but are considering the perspectives and potential actions of other crows.
Counting and Consciousness
In 2024, researchers in Germany taught crows to count out loud, associating specific vocalizations with numerical values. This ability to understand and express quantities is comparable to the skills of human toddlers. Andreas Nieder and his team at the University of Tübingen discovered that crows have sensory consciousness, meaning they experience the world subjectively.
“The neurons that have been found in humans and monkeys, and now in crows, are behaving exactly the same way,” Nieder stated. This challenges the previous assumption that such levels of consciousness were exclusive to humans and primates with a neocortex—a part of the brain crows lack.
A New Perspective on Evolution
These discoveries have significant implications for our understanding of evolution and intelligence. Since birds and mammals diverged on the evolutionary tree around 320 million years ago, they have developed different brain structures. Yet, crows demonstrate cognitive abilities similar to those of primates.
“It seems that evolution invented a different anatomical structure to give rise to the same physiological properties, and therefore also cognitive behaviors,” Nieder explained. This suggests that intelligence can evolve in different forms across species, much like how wings have evolved in both birds and bats for flight.
Communication and Social Behavior
Researchers like Doug Wacker from the University of Washington Bothell study how crows communicate in their natural environments. At the largest crow roost in the Seattle area, Wacker observes up to 20,000 crows gathering during certain times of the year. He uses artificial intelligence to analyze their calls, aiming to understand the meanings behind different vocalizations.
While the research is ongoing, initial findings indicate that crows have a complex system of communication, possibly conveying detailed information about food sources, dangers, and social interactions. This rich social life further emphasizes the advanced cognitive abilities of crows.
The Migration Mystery
Another intriguing observation is the potential migration of crows from their traditional roost in Bothell to a new location in Redmond. Wacker and his team noticed that thousands of crows flew past the usual roosting site, heading to the new wetlands. This could be the first documented case of such a natural shift, providing insights into how crows adapt to environmental changes.
“We’re seeing something that hasn’t been described,” Wacker said. Understanding these movements could help scientists learn more about crow behavior and their responses to habitat changes.
The End of a Long Experiment
John Marzluff plans to conclude his long-running mask experiment, noting a decrease in the crows’ reactions over time. As the original crows have passed away and new generations take their place, the intensity of the response to the caveman mask has diminished. Marzluff is interested in seeing how these behaviors fade from the crow society.
“I’d like to get one more measure as a way to see how these behaviors might eventually leave the society,” he said. This could provide valuable information on how learned behaviors are transmitted or lost over generations in animal communities.
What Crows Teach Us
The study of crows reveals that they are not just ordinary birds but intelligent beings with complex social structures and impressive cognitive abilities. Their capacity to remember human faces and hold grudges for years underscores the depth of their memory and social learning.
For young readers and curious minds, crows offer a glimpse into the diverse ways intelligence can manifest in the animal kingdom. They challenge us to rethink our perceptions of “bird brains” and appreciate the intricate behaviors of creatures we might otherwise overlook.
Conclusion
Crows are redefining what it means to be intelligent animals. Their remarkable memories, problem-solving skills, tool use, and social complexities show that they are far more advanced than previously thought. These findings encourage us to respect and protect these intelligent birds, recognizing that they have rich mental lives and can even remember how we treat them—perhaps for nearly two decades.
As we continue to study and learn from crows, we gain not only scientific insights but also a deeper appreciation for the natural world. Their ability to hold grudges against humans serves as a reminder that our actions towards animals have long-lasting impacts. Who knows what other secrets lie within the minds of crows, waiting to be uncovered by future generations of scientists?
