Researchers studying animal personality are interested in individual behavioural variation. It is crucial to consider behavioural variation as it is related to life-history, demography, dispersal, the distribution of individuals within habitats and social evolution, to mention just a few. Variation is not only the raw-material for natural selection to work on, but actually also the result of natural selection.
Two broad approaches to measure personality exist. Behaviours can be measured directly via observation across different environmental conditions and/or over time. However, in situations where the direct measurement of behaviour is not feasible, using behavioural ratings acquired by e.g. questionnaires is a fruitful alternative.
Previous studies on elephant personality have mostly been performed on zoo individuals and sample sizes were usually not high. These studies suggest that elephants have four or five personality dimensions and that some of those dimensions are related to status, age, stress or genetic factors.
We investigate if individual Asian elephants have different personalities. What kind of personality traits do they express and how do these differ between individuals? Is personality related to e.g. age, sex, origin or tuskness? Does personality affect the elephants’ social organization, maternal and allomaternal behaviour and ultimately fitness?
We perform questionnaires, asking the oozies to rate 28 traits on a scale from 1 (trait very rarely expressed) to 4 (trait very often expressed). The 28 traits include e.g. aggressiveness, friendliness, socialness, timidity, inquisitiveness and are well explained and defined in the questionnaires. Oozies know their elephants best and they help us to define the personality of each elephant. Using multivariate statistics we aim to disentangle the underlying personality factors influencing these 28 traits.
Our study which came out in Royal Society Open Science (DOI: 10.1098/rsos.172026) illustrates that personality in elephants of our population manifest as three distinct factors. We labelled these factors as Agreeableness, Sociability and Aggressiveness and they are partly similar to what a previous study had found in African and Asian elephants. These three dimensions also show some interesting parallels to the human Big Five personality structure and to the personality of other non-human primates. We also investigated differences in personality structure between the sexes but did not detect any; however there were slight differences in trait loadings on each factor between male and female elephants.
However, in our recently published paper in Scientific Reports (https://rdcu.be/boqjO) we found that despite there being no structural differences in personality between the sexes, males scored higher on the Aggressiveness personality trait compared to females. Males also tended to be rated as less sociable than females, scoring lower on the Sociability personality trait than females. We found no sex difference in the Attentiveness personality trait or in variances of any of the personality traits examined.
Watch this space in the future for more exciting research and to find out if personality is also related to elephants’ social behaviour, stress physiology, health and fitness. We also plan to look at the potential link between the elephants’ personality and the personality of their mahouts.