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Alex, Clever Hans and Chaser: the animals that revolutionised science

Dernière mise à jour : 17 févr.


Alex the parrot and Chaser the dog with Dr Pilley

Alex - The Alex Foundation / Chaser et Dr Pilley - American Kennel Club


Today, I wanted to write a lighter article, a playful reflection, so to speak. That's why I decided to put together a list of famous animals in the world of science and explore what they have taught us.


In the field of research, certain animals have distinguished themselves by their incredible mental capacities and their influence on our understanding of animal behaviour. Among these furry and feathered heroes, three emblematic figures have captured the imagination of the public and researchers alike: Alex, Clever Hans and Chaser.


1. Alex - The polyglot parrot

Alex, a grey parrot from Gabon and the subject of Dr Irene Pepperberg's study, has gone down in history for his unique ability to mimic human speech. His mastery of several hundred words to describe objects and his ability to work with numbers have astounded scientists. Alex has demonstrated the plasticity of the avian brain and opened up new avenues for understanding the linguistic and cognitive capacities of birds.


Clever hans cheval

Mary Evans Picture Library/Alamy


2. Clever Hans - The counting horse

Clever Hans, a German horse from the early 20th century, became famous for his amazing mathematical skills. It was thought that he could solve simple mathematical problems by tapping his hoof, but studies by psychologist Oskar Pfungst revealed that he actually reacted to the involuntary subtleties of his trainer's facial and body expressions. Although Clever Hans is no mathematical genius, his story has made scientists aware of the importance of controlling human bias in animal research and of the extraordinary ability of animals to perceive non-verbal signals.


3. Chaser - The border collie who knew over 1,000 words

Chaser, a border collie owned by psychologist John Pilley, demonstrated an exceptional understanding of words and objects. She learned to identify more than 1,000 different toys and to associate each of them with a specific name. This feat paved the way for more in-depth study of dogs' learning capacity and the way in which they process information. Chaser has shown that dogs, far beyond simple conditioned reflexes, can understand and apply complex concepts.


4. Honourable mention for all the other animals: a patchwork of scientific contributions

As we explore the diversity of animals that have left their mark on scientific history, we need to recognise the exceptional contribution of many other species.


ver C. elegans et la mouche des fruits, D. melanogaster
Le ver C. elegans et la mouche des fruits, D. melanogaster / flickr

The laboratory mouse, Mus musculus, has been an essential model in biomedical research, from genetics to neuroscience to cancerology. Chimpanzees, our cousins in the animal kingdom, have played an essential role in the development of vaccines against infectious diseases such as hepatitis and HIV. Less glamorous, but just as important, the worm Caenorhabditis elegans and the fruit fly, Drosophila melanogaster, recognisable by its characteristic red eyes, have had a colossal impact on biological research, enabling us to better understand the ageing process for the former, and shedding light on key aspects of heredity and embryonic development for the latter. Both species have provided crucial information for understanding biological mechanisms in mammals, including humans.


In conclusion, these tales of animals that have left their mark on the history of science remind us that the animal kingdom is truly a treasure trove of surprises and wonders. Whether through the astonishing linguistic abilities of Alex, the observational skills of Clever Hans, or the remarkable intelligence of Chaser, each story reveals a unique aspect of the intelligence and adaptability of animals. These furry and feathered heroes have left an indelible mark on the history of science, helping to broaden our vision of animal intelligence. They have also served as catalysts for major scientific breakthroughs, shedding light on key aspects of cognition, behaviour and biology.


However, while celebrating these successes, it is crucial not to ignore the ethical issues surrounding the use of animals in research. It is imperative that we recognise the need to treat animals with respect and continue to explore ethical alternatives that allow science to progress without compromising their welfare. Even without mentioning emblematic cases such as Laïka, it is important to emphasise that even today, in France, more than a million mice are killed every year for scientific purposes.


Broadening our understanding of the world around us cannot be achieved at the expense of the well-being of the animal species that play a fundamental role in this process. By adopting a scientific approach rooted in sound ethical principles, we can ensure that our discoveries benefit not only humankind, but all living species. In this way, we can strike a harmonious balance between the pursuit of scientific knowledge and respect for animal welfare.


Do you know of any other animals that deserve to be on this list? Feel free to share your examples in the comments.

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