Monkeys on Thai island started using stone tools when Covid stopped tourist inflow: Study

'Life finds a way' is a common refrain used to describe the wonderful ways in which nature exhibits its complexities and marvels when faced with an impediment. Adaptation has been a key for survival for millions of years. And sometimes the constant endeavour of living beings to fight their way through the struggle of life churns out funny phenomena. In this case, monkeys in Thai tourist hotspot learnt to use stone tools when Covid pandemic in 2020 put severe restrictions on tourism worldwide.

The monkeys in this case are common long-tailed macaques (Macaca fascicularis fascicularis). There is a sizeable population of them on Koh Ped, an island close to Pattaya, Thailand.

The island is a tourist hotspot with visitors taking a boat ride to reach it. In fascination or as a way of showing some love to the animals, the tourists used to feed mangoes, cucumbers and nuts to monkeys.

Then came the pandemic. The tourism industry was hit hard and the monkeys on Koh Ped were deprived of the food offered by tourists.

And this led to a wonderful development.

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A research team, led by Suchinda Malaivijitnond from Chulalongkorn University in Bangkok has been studying these monkeys for decades.The team never observed the monkeys using any kind of tools before pandemic.

But when the researchers returned to the island last year, they were in for a surprise.

The monkeys, increasingly forced to be self-reliant for food, had taken to opening sea shells with the use of rocks as tools. Initially the team observed that just two of the monkeys were using stones to open shells. When the team made another visit this year, it found that the behaviour had spread in the population. 

"Several other groups of primates use stone tools, but we haven’t been able to study the origins of this behaviour before," says Jonathan Reeves at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany

He was quoted by The New Scientist.

“We…can observe it and we get to see it, but seldom do we get the chance to see it emerge as a new behaviour in a population.”

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The technique

It was seen by the research team that the monkeys placed the shell on the ground, found a rock which they thought was of adequate size, lifted it to shoulder level and dropped it on the shell.

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This may get categorised as a crude method but it can be emblematic of how our biological relatives in the animal world improvise in the face of adversity. A trait we all display.

The study was published in Science Advances in March this year.

(With inputs from agencies)