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published on 8 January 2021 in life

Smart as a crow

Some people call them “monkeys with feathers” because they can do clever things comparable to many of our monkey cousins. They use tools, or rather, modify small sticks and leaves to obtain the tools most suitable for carrying out simple tasks, like extracting food from a hole in bark, just as chimpanzees do when, with a stick, they catch termites in their nests. Similar skills but different brains. The brains of birds are very different from those of mammals, which is not surprising given that the last common ancestor between us and crows and chickens lived 320 million years ago. For example, we mammals have the cerebral cortex, the outermost layer of the brain, which plays a key role in the most complex functions and intelligence. Birds don’t have one: so how can they be so smart? Recent research by two German universities finally explains why crows and other feathered marvels, such as parrots, are exceptionally intelligent. In the brains of birds, there is a part called the “pallium”, and according to researchers, it is precisely the part of the brain responsible for the birds’ mental abilities. The pallium therefore does in birds what the cortex does in mammals.

There is another very obvious difference between the brains of mammals and of birds: size. For equal performance, birds have small brains when compared to mammals. And yet they work perfectly. How come? We know that neurons are the brain cells that carry nerve impulses. Neurons form complex networks and it is thanks to these that the brains of all animals function. In our brain, for example, there are about 90 billion interconnected neurons that collect information, process it and respond with actions, thoughts, dreams, emotions… That is, with the mind.

Comparing brains. Credits: Pavel Nemec, Charles University, Prague

Birds’ neurons are smaller than those of mammals, but they are closer together, so if a crow’s brain were as big as ours, the number of neurons would be higher… maybe twice as many, so perhaps a crow would even be smarter than us. Why do birds have tiny brains? Evolution provided them with small but powerful brains to meet the need for a lightweight body suitable for flight. A small brain with amazing performances, like language. We know that parrots are very skilled in imitating sounds, even human words. And that’s not all: a study of wild parrots in Venezuela showed that in communities of green parakeets each one has its own name. These small parrots live in very crowded communities and are virtually identical to each other. It’s very hard even to tell a female from a male. How do they recognise each other, for example, parents and baby birds when they gather by the hundreds in the branches of the forest? By analysing the sounds made by adults returning to the nest, the researchers found that each parrot is given a name at birth, just as we humans are. And just like humans, a parrot’s name accompanies it throughout its life. Amongst parrots, therefore, they call each other by name. The researchers also found that when a parrot returns to its nest, it greets its mate with specific “words” and the female responds by giving it a kind of “welcome back.”

Parakeets

The champion of feathered chatter was Alex, an African grey parrot. Over the course of his life, spent in close contact with Irene Pepperberg, the American scientist who raised him, Alex learned over 100 words (in English) but more importantly, he showed researchers that he could construct simple sentences, point to objects with the correct name, express a willingness to do something or refuse to do it when he didn’t feel like it. Alex could count up to 6 objects, he could name some colours (including his own, grey), he could distinguish shapes and materials. Alex died at the age of 31. The night before he died, he said goodbye to Dr. Pepperberg and said: “You look good. I love you. See you tomorrow.”

The next time we see a chicken, a crow or a pigeon, we will be sure to feel a little disturbing embarrassment.

By Andrea Bellati

 
 
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