Have you ever heard an old hunter’s tale about counting crows?
The story is about three hunters waiting in a hiding place near a murder of crows roaming for food. Silently, crows watch the hunters from a safe place. After not seeing any crows in the predicted area, one hunter finally gives up and leaves. The crows still wouldn’t come out, though. Another hunter leaves and the crows still don’t budge. It’s only after the last hunter leaves that the crows resume their normal feeding activity.
In myths around the world, crows represent tricksters, spies, allies, and sacred beings. Although different from one culture to another, many of the old tales indicate that crows are enigmatic and scary smart.
Scientific studies have also revealed the intelligence of crows is actually more than a myth. Crows have advanced intelligence—they know what they know. Not only that, they can also solve problems.
How Smart are Crows?
Crows can Engineer Tools
According to one study (Rutz et al., 2016), New Caledonian crows have the ability to craft hooks to probe for food. They break side branches from plants and then create a terminal hook from a part of the branches, which are connected to the main stem.
Some of the crows even go to great lengths by bending the end of the branches, creating extra curvature on the tools.
Scientists have found evidence of carrion crows being able to recognize numbers of items (Ditz & Neider, 2015). They used a computer screen to play a numerical matching game and trained crows to recognize groups of dots on the screen.
The study showed crows could tap the screen when the same numbers of dots appeared or refrain from pecking when the numbers did not match. It also indicated neurons in a specific area of the brain showed a peak activity associated with the number of dots on the screen.
Problem Solving Skill
When we are trying to solve a problem, we usually make an important step called “preplanning,” before we move on to execute our actions. We can imagine a solution to our problem along with all of the stages, similar to a chess player thinking several moves ahead.
Planning and using tools are powerful cognitive skills that humans have. Like humans, New Caledonia crows can also plan several steps ahead to solve a problem (Gruber et al., 2019). The crows noticed tools and the location of tools before using them to execute the plan.
Watch the video below to see how a crow plans and solves a problem.
Crows Know Familiar Faces
Crows are able to discriminate between human faces; furthermore, they can recognize familiar faces and associate their experiences with a human face (Marzluff et al., 2012).
Based on a study, upon viewing a familiar face of a person who caught them previously, crows froze and responded with a fixed glaze as measured as decreased blink rate. Recognition also activated a certain region of the brain, stimulated by fear.
On the contrary, when seeing a person who cared and fed them, crows blinked more, and recognition activated a different part of the brain. This region is usually associated with learning, motivation, and hunger in vertebrates.
Crows Have a Basic Form of Consciousness
We have the ability to know and analyze the content of our mind based on our subjective or personal sensory experience. In short, it’s the ability to have a point of view. As an example, our subjective experience with the sweetness of Reese’s peanut butter cups, the blueness of the ocean, or the tingling sensation of cold soda. This basic type of awareness, also reported in other primates, refers to sensory consciousness.
In a recent study (Nieder et al. 2020), scientists trained two carrion crows to report if they saw light or nothing at all. A red cue meant the crows should peck the screen as a “yes” if they saw something. Whereas a blue cue meant “no,” they do not see anything.
Then, the researchers kept switching the rule during trials. In some trials, the red cue signaled “yes,” whereas in other trials, the blue cue signaled “yes.” These trials required the crows to analyze quickly about what they had seen before reporting. The researchers also monitored the crow’s brain activity. If the bird said “yes,” the nerve activity increased, whereas “no” resulted in flat activity.
The results of this study showed that faint light elicits different responses from the two tested crows—sometimes they reported “yes” and sometimes “no,” indicating subjective sensory experience. Professor Andreas Nieder said, “This cannot be explained by the workings of the eye, but must arise at higher processing levels of the brain that ‘evaluate[s]’ the sensory input.”
Some birds, such as crows, are remarkably smart and can perform many cognitive skills, although their brains are relatively small. The anatomical structure of their brain is completely different from the structure of humans and other primates.
Inside the Avian Brain
Unlike our complex brain, avian brains lack a cerebral cortex, which is associated with advanced cognitive skills. What they have instead is a special structure in the forebrain, called pallium.
From its appearance, the pallium looks similar to lumps of grey cells. Nevertheless, in term of numbers of neurons in the forebrain, the bird's brains are comparable to some mammals. Some birds, such as corvids (a group of birds that includes crows and ravens belonging to the Corvidae family) and parrots, have very large numbers of neurons in their forebrain, more than those found in some mammals (Olkowicz et al., 2016).
The mammalian cerebral cortex consists of a six-layered neocortex. However, the avian pallium has a simple multinuclear structure, called the dorsal ventricular ridge or DVR (Jarvis, 2009). Only one of these nuclei, Wulst, is homologous to the mammalian neocortex as a feature of the avian sensory forebrain.
In a recent study, scientists examined the avian brain more closely. Surprisingly, similar to the mammalian neocortex, the arrangement of neurons in the avian sensory forebrain is in vertical layers and horizontal columns (Stacho et al., 2020).
Possible Convergent Evolution
In birds and mammals, it’s possible that cognitive skills evolved independently. However, the similarity of neuron organizations between mammalian neocortex and avian pallium could provide another possibility for a precursor of these brain structures. This precursor might come from the last common ancestors of birds and mammals, but then evolved independently (Stacho et al., 2020).
The discovery of neuron organizations and sensory consciousness in crows is groundbreaking. Although crows have a different brain structure than the human or primate brain, they possess impressive cognitive skills. This finding also paves the way for researchers to explore more about the evolution of intelligence in other closely-related species.
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