This Bizarre Experiment by Scientists Proves That Crows are Smarter Than We Think!

Experiment by scientists with Corvus shows that New Caledonian Crows are on an early stage of cultural and intellectual evolution

Crows are smart

In this huge variety of animals, humans can be identified separately. It seems that all of the evolutionary journeys came together, suddenly people went far away from the rest of them from the rest. The scientists have naturally awakened questions: How did our intelligence evolve? 

How newer generations are more advanced than the previous ones?  Why has this intellectual evolution only occurred in humans? Did any animal except homo sapiens went through the same sort of evolution? In answer to that, some sensational possibilities have been seen in a particular species of crow.

Although all of these questions might seem easy, their formula is actually hidden among these two words: "culture" and "cultural evolution."

Almost every kind of animal learns so many things from their surrounding environment, which are also expressed in their behavior. 

The various behavior derived from this "environmental education" is called "culture" according to sociologists. It is fairly accepted that cultural diversity in nature is a common matter.

But human intellectual progress can't be understood only by the knowledge achieved in one generation. It is very important to take social education for this and keep them in the next generation. 

We, human beings observe a lot from our surroundings, we learn so many things, we also memorize some, but most of the time we forget them again.

In this case, there could be three things. One, I saw but did not learn anything. Two, I saw, I learned but I could not teach anyone else by holding on to that education. 

And three, I saw, learned, and taught the other generation like an experienced person or the new generation learned by watching. 

When this last condition occurs, many social educations can be passed down from one generation to the next.

Apart from genetic evolution and environmental influences, people have been able to go so far only through the accumulation of social education. 

Demonstrated all the abilities that an individual can never achieve alone. This achievement cannot be given to any other animal except man. Although "culture" is normal, this "gradual cultural evolution" is very rare in the animal kingdom.

Incidentally, one of the main differences between cultural evolution and genetic evolution is that the second evolution does not fit into the genetic code. 

That is, for the second evolution, the next generation has to learn from the elders at their own urging. That teaching does not come automatically at birth.

San Bushmen making a fire
San Bushmen making a fire using primitive tools

But man, before becoming civilized in today's sense, left the whole animal kingdom behind. For example, the Bushmen or the San people, who live in the Kalahari Desert of Africa, knows the fruits and leaves of a tree, their food, how to collect them in different climates, how to make arrows or bows, how to search for water, and much more. 

People who live in the Arctic or the deep jungle also know a lot about their needs.

To live in Kalahari, Arctic-Antarctic, or deep jungle, they have to use different knowledge, education, or instruments/parts. 

But the owners of all this knowledge or education are of the same species, humans. We have acquired different kinds of knowledge with the same kind of brain. 

This vast diversity is not found in any other animal. It is conceivable that this would never have been possible without the "cumulative cultural evolution".

Archaeological evidence suggests that humans have gradually "culturally evolved" to adapt to nature, the environment, and the situation, as evidenced by the variety of tools or utensils discovered nearly ten thousand years ago. 

Various Stone Age materials suggest that this "cultural evolution" of our ancestors began about 1.6 million years ago.

There are many opinions as to why this cumulative cultural evolution is so rare. Some scientists say that being able to imitate has a big role to play in social studies. Only if they can successfully imitate their parents or other teachers then the next generation master a new power.

Scientists in this group, therefore, point to the inability to imitate as one of the reasons for the lack of cultural evolution among other species. However, according to another group, the concept of social education is a bit narrow: there may not always be a need for direct imitation. 

It is necessary to have a close acquaintance with the objects created by the previous generation. There is no need to duplicate those steps by looking at how the elders are creating the object. 

In some cases, the new generation can master the methods of making the object that has been created by manipulating it. For this, the last object does not need to be in front of the eyes. Even If you haven't ever seen it before.

According to a group of scientists, direct imitation may not be necessary for learning, as long as there is a close acquaintance with the objects created by the previous generation.

Naturally, this idea is a matter of debate. And even in evidence. In search of that evidence, a team of scientists from England and New Zealand conducted a bizarre experiment with the Crows. The study was published in the journal Nature in 2018.

People who have not seen crows are rare. Many times they are called broomsticks, but in the storybooks, we have all seen the intelligence of some people. 

Who doesn't know the story of quenching the thirst by throwing the pebbles and bringing the water of the jug to the top and drinking that water! But, it is not like only crows are the only Aves who show some culture.

Many birds build their own nests, which are undoubtedly architectural monuments. The precise migration and return of migratory birds from one country to another is a sign of their collective intelligence.

However, the New Caledonian crows were chosen for the test. They are found on an island near Australia-New Zealand. One of their features is that they can tear off the leaves of pandanus species and make tools for any work they need. 

For example, they cut the leaves with their lips and bring them to a certain size so that they can easily do what they need.

At least three completely different designs of parts made from this page have been identified, from which it can be inferred that these different designs have originated for different needs. One of the designs is much more intricate than the rest. 

Therefore, it can be said that it started with a simple instrument, but gradually it became complicated. So, there is a hint of cultural evolution, albeit a slight one, in these crows.

But none of them showed the complexity of the language required for teaching or the tendency to imitate. So, the only explanation behind their ability to make parts was to keep them alive for generations and to sharpen that ability. 

They may be able to make a ready-made order just by looking at the leaf machine. Scientists tested this explanation with a surprising experiment.

Some special vending machines were built for this test, where a piece of paper of a certain size was thrown out to bring out the food. 

This time the crows were given some special-sized pieces of paper in front of a vending machine. At first, crows were trained with two types of pieces of paper.

8 pieces of very small paper were cut (15 x 25 mm), no food would come out by inserting these papers. The second 8 large pieces of paper (40 x 60 mm), inserting them there will be food coming out. 

The crows were trained for 2-4 days. When the training was over, they learned to draw food with 8 correct-sized (40 x 60 mm) paper and did not use any small size paper.

This time two large pieces of paper (10 x 10 cm) were given to the crows without any correct sized pieces of paper which would not fit into that particular vending machine in any way. 

Now the only way to get food out of the vending machine is to cut the paper into small pieces so that it fits the size of the sheath. 

All that is needed to do this is to memorize the size (or template) of the paper from previous experience and to create new tools/parts (in this case small pieces of paper) from that knowledge that will make the current work easier and more successful.

What did the New Caledonian crows do in this case? Were they able to cut the large piece of paper into small pieces and extract the food from the vending machine? 

Surprisingly, yes. With the help of their lips and feet, they were able to cut the large piece of paper into small pieces and extract the food.

Not only that, for the second time, the crows were trained in the exact opposite way, where a small piece of paper (15 x 25 mm) is put in a vending machine and the food will come out. 

And the strange thing is that these New Caledonian crows were able to extract food out of the vending machine by cutting small pieces of paper with that template in mind. (Image 1)

Scientific experiment with New Caledonian Crows
Scientific experiment with New Caledonian Crows
In other words, these crows can remember the size of a piece of paper that will be useful. Since a piece of paper and a pandanus page are not the same things, it can be assumed that no effect of previous education has been found in this test. These crows created a new thing by remembering it and then by their own efforts.

According to scientists, this is how the cultural evolution of this species of crow has taken place in nature. 

The children saw their elders use the torn leaf instruments, then remembering that instrument and later making them themselves. Scientists call this the "mental template matching hypothesis."

This is also seen in the case of birds learning to sing. A juvenile bird first listens to the song from their peers and creates a template in their mind, then expresses it in their own throat and tries to match their own throat perfectly with the melody they remember. 

As a result of creating templates in the mind, when they create something in a new way, there is no need to keep that object or subject next to the eyes/ears. 

So if something new is added during the making of that device, it is also transmitted to the next generation and increases the chances of being transformed into a more advanced or complex device. This process is the initial stage of "cultural evolution".

Notably, experimental evidence of this first mental template matching hypothesis was found in the laboratory. 

However, researchers also say that even if cultural diversity is introduced in this way, something very complex may not be possible. For that matter, the complexity of language and the ability to imitate might be important.

In a word, this test proved that people are far, far ahead, but not alone. Evidence of early stages of cultural evolution has also been found in other species.

Author: Amalesh Roy, currently the Research Manager at Sun Pharma, Ranbaxy Division. Post Doc from Max Planck Institute and Ph.D. from IACS Calcutta.

Notes and references:

  • [1] Mental template matching is a potential cultural transmission mechanism for New Caledonian crow tool manufacturing traditions, S. A. Jelbert, R. J. Hosking, A. H. Taylor & R. D. Gray, Scientific Reports, volume 8, Article number: 8956 (2018) (
  • [2] R. Boyd* & P. J. Richerson, Proceedings of the British Academy 1996, 88, 77-93
                                                                                                                                       Cover Image by Tyler Quiring on Unsplash

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