Dolphins ‘have developed similar personality traits to humans’

Dolphins have similar personality traits to humans and other primates like monkeys and apes, a new study claims.

Psychologists at the University of Hull studied 134 bottlenose dolphins across eight countries for their almost decade-long study.

Just like primates, the aquatic mammals displayed curiosity, sociability and a personality trait that is a blend of ‘extraversion and agreeableness’, they found.

Dolphins have slightly different psychology to the ‘big five’ model – which is commonly applied in academia to describe humans, according to the authors.

It’s already known monkeys and apes have similar personality traits as humans, but this study claims to be the first to investigate if the same traits exist in dolphins.

New research from the University of Hull has found dolphins to be far more similar to humans and other primates than previously thought. Pictured, bottlenose dolphins (Tursiops truncatus)

The study began in 2012 and has finally been published this year in the Journal of Comparative Psychology.

‘Dolphins were a great animal for this kind of study because, like primates, dolphins are intelligent and social,’ said Dr Blake Morton, a psychologist at the University of Hull.

‘We reasoned that if factors such as intelligence and gregariousness contribute to personality, then dolphins should have similar personality traits to primates.’

Despite being adapted to an aquatic lifestyle and last sharing a common ancestor with primates 95 million years ago, bottlenose dolphins (Tursiops truncatus) resemble non-human primate species in ‘several behavioural and cognitive traits’.

Both chimpanzees (Pan troglodytes) and bottlenose dolphin live in communities, which are described as ‘fission-fusion’ societies.

The chimpanzee (Pan troglodytes), also known as the common chimpanzee, robust chimpanzee, or simply chimp, is a species of great ape native to the forest and savannah of tropical Africa. Like Pan troglodytes, dolphins live in fission–fusion societies, use tools, and have relatively large brains

Bottlenose dolphin communities around the world are described as ‘fission-fusion’ societies.

This means that individuals associate in groups dynamically – they merge or split within the same aggregation several times per day.

It has been seen that some societies live in large mixed-sex groups with strong associations within and between the sexes.

In the past, bottlenose dolphin groups have been referred to as pods – social groups of unchanging composition.

More recently, long-term studies of bottlenose dolphins have now shown that their group composition changes.


This means their group size and composition changes frequently within the lifetime of members – they split (fission) or merge (fusion).

Chimps and dolphins also both use tools and have relatively large brains, Dr Morton and his colleagues point out in their research paper.

As for humans, according to a psychological trait theory developed in the 1980s called the big five, human behaviour is comprised of five personality traits that form the acronym OCEAN – openness, conscientiousness, extraversion, agreeableness and neuroticism.

Extensive studies have looked at the extent to which these traits are shared by primates but his team wanted 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,’ Dr Morton told the PA new agency.

To determine the extent to which these and other factors contribute to the evolution of dolphin personality, the team examined personality structure in 134 bottlenose dolphins – 56 male and 78 female.

The dolphins were observed a different facilities across eight countries, including Mexico, France, the US, Curacao, the Netherlands, Sweden, the Bahamas and the Cayman Islands.

Researchers assessed each dolphin’s personality using questionnaires given to staff from each facility who knew them well.

The ‘big five’ personality traits are the best accepted and most commonly used model of personality in academic psychology

Researchers found dolphin behaviour almost aligns with this model.

The big five model is the most widely accepted personality theory held by psychologists today.

The theory states that personality can be boiled down to five core factors, known by the acronym OCEAN:

  • Openness to experience (inventive/curious vs. consistent/cautious)
  • Conscientiousness (efficient/organised vs. extravagant/careless)
  • Extraversion (outgoing/energetic vs. solitary/reserved)
  • Agreeableness (friendly/compassionate vs. critical/rational)
  • Neuroticism (sensitive/nervous vs. resilient/confident)

Source: Simply Psychology/Open Psychometrics

‘We found four domains,’ the team say in their paper.

‘Three – openness, sociability, and disagreeableness – resembled personality domains found in nonhuman primates and other species.’

The fourth, directedness, was a blend of high conscientiousness and low neuroticism and was unique to dolphins.

Despite this, dolphins are still impressively similar to us, the experts suggest.

‘Dolphins, like many primates, have brains that are considerably larger than what their bodies require for basic bodily functions,’ said Dr Morton.

‘This excess of brain matter essentially powers their ability to be intelligent, and intelligent species are often very curious.

‘Throughout our lifetime, we interact and form relationships with a wide variety of people – dolphins do the same with each other.

‘Collectively, being smart and social, regardless of what ecosystem you live in, may play an important role in the evolution of certain personality traits.’

Dr Morton emphasises that this is only the beginning in terms of identifying the full spectrum of traits exhibited by dolphins.

‘It is vital researchers conduct further studies because not only will it lead to a better appreciation for species living within the depths of our oceans, it will lead to a better understanding of ourselves,’ he said.