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Kinji Imanishi was born on 6th January 1902 and died on June 15th 1992. He was a pioneer of primatology, the recognition of animals as individuals and the bonds and friendships that form between individuals within family groups. His work has paved the way for numerous studies into the complex social and cultural lives of animals.

During the second world war, Imanishi studied wild horse societies in Mongolia, and based his research on the individual recognition of each horse, which was highly unusual for the time. On December 3rd, 1948, Imanishi went to Koshima island to study wild Japanese macaques. Here he developed his unique style of field research of individual recognition, habituation, and long-term observation. This method of study remains a standard technique of fieldwork on nonhuman primates today.

Thanks to the efforts of Imanishi and his colleagues, we now have in depth knowledge of wild macaque social lives and behaviours. Imanishi and his team recognized a distinct breeding season, discovered the matrilineal residence with females staying in the family group in which they were born and males migrating from the natal group to others. Females remain in the group to form a matrilineal society. They noted the dominance hierarchy, they documented over 30 different vocalisations each with different meanings being understood by others in the social group, and they found evidence of culture illustrated by the now famous sweet-potato washing macaque ‘Imo’.

Imo, a young female macaque, was observed dipping sweet potatoes into a nearby river before eating it and researchers concluded that her reason was simple and entirely reasonable: she saw sand on the potatoes and wanted to wash it off. Young macaques watch their elder family members and have subsequently learned this behaviour too. Evidently, this monkey family had discovered the joys of eating clean potatoes.


Over the next few years, research staff observed this new behaviour spread through the entire macaque colony, and within a decade, every capable macaque on the island was washing potatoes. But it was not only the technique of potato washing that the monkeys learned. At some point Imo discovered a second trick to make her potato consumption more pleasurable, by dipping her potatoes in the ocean instead of the river, the saltwater would season the potato and make it taste better. After each bite, she would dip the freshly exposed section of her potato back into the sea to enhance its flavour. 

This same group of macaques also learnt to wash the sand off grains of wheat by throwing them into the ocean to clean them, with these new habits also spreading quickly through the macaque community.

These actions clearly demonstrate the three important aspects of cultural phenomena: emergence, transmission and modification, and sweet-potato washing is still one of the best examples of cultural phenomena in nonhuman animals.

After 10 years' of study on wild macaques, Imanishi went to Africa where he set up a study of wild chimpanzees at Mahale in 1965. This study and the now more famous study of Gombe’s chimpanzees set up by Jane Goodall have changed our perception of both chimpanzees and animals in general, taught us the value of recognising animals as individuals and the importance of understanding their complex social lives if we are to conserve them and their cultural behaviours in the future.  For more details of the work of Kinji Imanishi please see this article ‘Kinji Imanishi and 60 years of Japanese Primatology’

On this day Jan 6th 2023 we celebrate the life of Kinji Imanshi, the legacy his research methodology has left us with and the knowledge that we now have of the complex social, emotional and cognitive lives of animals, thanks to his pioneering work.

The details above has been adapted from this article 

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