The researchers collected data for the study with questionnaires on the elephants personalities.
Elephants have unique personalities just like humans, say scientists who have identified three traits - attentiveness, sociability and aggressiveness - in the giant mammals.
As is commonly known, people have different personalities, and the structure of human personality can be divided into five factors.
Other species behaviour also differs between individuals: some are braver, more social, or aggressive than others.
Researchers of the University of Turku in Finland studied a timber elephant population in Myanmar and discovered that Asian elephant personality manifests through three different factors - attentiveness, sociability and aggressiveness.
"These kinds of consistent differences in behaviour are called personality. Personality studies on other species than humans have so far focused on primates, pets and zoo populations, or on species that have a relatively short lifespan," said Martin Seltmann, postdoctoral researcher at University of Turku.
"Besides humans, personality studies on other long-lived species living in their natural habitat are rare," said Seltmann, lead author of the study published in the journal Royal Society Open Science.
Researchers found that male and female elephants do not differ in these three personality factors.
"Attentiveness is related to how an elephant acts in and perceives its environment. Sociability describes how an elephant seeks closeness to other elephants and humans, and how popular they are as social partners," said Seltmann.
"Aggressiveness shows how aggressively an elephant acts towards other elephants and how much it interferes in their social interaction," he said.
The researchers studied the personality of over 250 timber elephants living in their natural habitat in Myanmar.
"The elephants work in the timber industry, pulling logs from one place to another. This is a very unique research environment and population, enabling us to study several hundreds of elephants," said Seltmann.
All the elephants work with their own mahout, ie an elephant rider. This social relationship can last throughout the elephants lifetime.
Therefore, the mahouts know the behaviour of their elephant very well and can give detailed information on their personalities.
"We met elephants that were clearly more curious and braver than others. For example, they always tried to steal the water melons that were meant as rewards," said Steltmann.
The researchers collected data for the study with questionnaires on the elephants personalities. The surveys were conducted in Myanmar in 2014-2017.
The questions were directed to the mahouts and they had to assess the elephants behaviour according to 28 different traits. The mahouts assessed how often the elephant displayed a particular behaviour on a 4-point scale.
"Elephants and humans have many similar characteristics in their life-history and behaviour," said Mirkka Lahdenpera from the University of Turku.
"Among other things, elephants have a very long lifespan and give birth to a single calf at a time, who in turn needs the care of the mother and other females for a long time after birth," Lahdenpera said.
"Living in complex social environments could be a reason why both species have developed such complex personality structures," she said.