Dolphins have developed a number of similar personality traits to humans, despite having evolved in vastly different environments, researchers have found.
A study, published in the Journal of Comparative Psychology, looked at 134 male and female bottlenose dolphins from eight facilities across the world, with each dolphin’s personality being assessed by staff at the facilities. The results of the study found a convergence of certain personality traits, especially curiosity and sociability.
The study has aided researchers in understanding how certain human personality traits developed independently of immediate environments. These similarities were found despite dolphins having evolved in a completely different environment from primates, with the last common ancestor living about 95m years ago.
Dr Blake Morton, a psychology lecturer at the University of Hull and the lead author of the study, said that this research was the first time the personality of dolphins had been studied in this way.
Morton said: “Dolphins were a great animal for this kind of study because, like primates, dolphins are intelligent and social. We reasoned that if factors such as intelligence and gregariousness contribute to personality, then dolphins should have similar personality traits to primates.”
He said: “Dolphins, like many primates, have brains that are considerably larger than what their bodies require for basic bodily functions; this excess of brain matter essentially powers their ability to be intelligent, and intelligent species are often very curious.”
Morton said that the most widely accepted model of human personality is defined by five traits, which are replicated everywhere in human personality regardless of environment. These traits can be summarised as openness, conscientiousness, extraversion, agreeableness and neuroticism. He added that although many studies have looked at the extent to which these traits are shared by primates, this study aimed to look at intelligent animals in a completely different setting.
“Scientists still do not fully understand why our behaviour comes down to those five traits, so one way of doing that is to compare ourselves to other animals – what we share in common and why,” he said.
“Most research has been done on primates so we decided to do something different and look at dolphins. No one’s ever studied personality in dolphins before in the way we have.”
Morton continued that although the personalities of dolphins had been shown to be similar to humans, the study had not concluded that these personalities were identical.
“I don’t want people to misinterpret that and say humans and dolphins have the same personality traits – they don’t. It’s just that some of them are similar,” he added.
The study, Personality Structure in Bottlenose Dolphins, began in 2012. Countries in which the facilities were based include Mexico, France, the US, the Bahamas and the Cayman Islands.
The team of researchers also included Dr Lauren Robinson from the University of Veterinary Medicine Vienna and Georgia State University, Dr Alexander Weiss from the University of Edinburgh, and Sabrina Brando from the AnimalConcepts.