Kinji Imanishi, the pioneering ecologist who recognised animals as individuals

06 January 2023

Kinji Imanishi was born on 6 January 1902 in Japan. 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.

Studying macaques

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. In 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 recognised 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. 

They noted the dominance hierarchy, documented over 30 different vocalisations each with different meanings being understood by others in the social group, and found evidence of culture illustrated by the now famous sweet-potato washing macaque ‘Imo’.

The sweet-potato washing macaque, Imo

Imo, a young female macaque, was observed dipping sweet potatoes into a river before eating them and researchers concluded that she wanted to wash sand from the potatoes. Young macaques watch their elder family members and have subsequently learned this behaviour too. 

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 another way to make potatoes taste better, by dipping them in the ocean 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.

This action clearly demonstrated 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.

Studying chimpanzees

After 10 years studying wild macaques, Imanishi went to Africa to  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. 

They’ve 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.

On this day January 6, 2023 we celebrate the life of Kinji Imanshi, the legacy of his research methodology, and the knowledge his pioneering work has given us of the complex social, emotional and cognitive lives of animals.

Read more:

‘Kinji Imanishi and 60 years of Japanese Primatology’