Dolphins and humans share common personality traits, despite evolving in vastly different environments. Researchers performed the study on over 100 dolphins from all over the world and found that they have remarkable personality characteristics. In particular, dolphins can be curious and sociable, two of the personality traits that define human behavior.

Dolphin qualities

Human personalities comprise five personality traits (which funny enough, spell OCEAN). The so-called ‘Big Five’ are:

• Openness (how open someone is to curios and playful activities). This can refer to imagination, insight, and a wide range of intellectual curiosities.
• Conscientiousness (how reliable and self-controlled someone is). This mostly refers to how organized someone is.
• Extraversion (how friendly and outgoing someone is). This trait characterizes individuals who are sociable and energetic among others.
• Agreeableness (how kind and helpful someone is). People who score high on this tend to be more affectionate, trustworthy and empathic.
• Neuroticism (how anxious, erratic, or unstable someone is). This is often associated with negative emotions such as anxiety, moodiness, irritability, or sadness.

It shouldn’t come as a surprise that humans have long-term personalities, but it could surprise you that dolphin personalities exist too.

Bottlenose dolphins are the most common type of dolphins and can be found everywhere except the Arctic and Antarctic. They have a “bottle-shaped” snout or rostrum, from which they get their name. But researchers are more interested in their mental abilities. Specifically, intelligence is an important dolphin quality — and bottlenose dolphins are renowned for their intelligence.

There are at least three species of bottlenose dolphins — the common bottlenose dolphin (Tursiops truncatus), the Burrunan dolphin (Tursiops australis), and the Indo-Pacific bottlenose dolphin (Tursiops aduncus). All of them have a very brain mass per body size (higher than any other animal except humans). Also, all bottlenose dolphins display high intelligence and social abilities. They live in societies and can even use tools.

Researchers like bottlenose because they’re also relatively easy to view in the wild. The dolphins live close to shore and are distributed throughout coastal waters, which unfortunately makes them at risk of human-related injuries.

Dolphin personalities

Bottlenose dolphins are among the most intelligent animals (if not the most intelligent) on Earth. But their personalities and psychological characteristics have been difficult to study.

To address this, a team of researchers from the University of Hull collected data on 134 common bottlenose dolphins from different facilities in Mexico, France, the US, Curacao, the Netherlands, Sweden, the Bahamas, and the Cayman Islands. The team was led by Blake Morton and gave questionnaires to the staff members who knew the dolphins well and could assess their personalities.

“Dolphins were a great animal for this kind of study because, like primates, they are intelligent and social. We reasoned that if factors such as intelligence and gregariousness contribute to personality, then dolphins should have similar personality traits,” Morton said in a statement. “They have brains considerably larger than that their bodies require for basic bodily functions.”

“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.”

This wasn’t the first time researchers looked at dolphin personality and psychological characteristics. In 2007, researchers from the University of Southern Mississippi analyzed dolphins in different situations, including captive dolphins that went through the trauma of Hurricane Katrina and had to be relocated. The researchers found that not only do dolphins have personalities — but these personalities are stable in time.

“The results support the notions that dolphins demonstrate different personalities and that these personalities are relatively stable over
time and across situations,” the researchers explain. Another study confirmed that dolphin personalities are stable for decades.

But the study by Morton and his team looked at intelligent animals in a completely different setting.

The personality traits of dolphins

Morton and colleagues wanted to see how dolphins relate to the ‘Big Five’ human personality traits (the OCEAN).

“Scientists still do not fully understand why our behavior comes down to those five traits, so one way of doing that is to compare ourselves to other animals,” Morton said.

The researchers found four domains for dolphin personalities. Three of them, which they called Openness, Sociability, and Disagreeableness, resembled personality domains found in nonhuman primates and other species. They’re also quite similar to the personality traits of humans.

The fourth, Directedness, was a blend of high Conscientiousness and low Neuroticism and was unique to dolphins. But humans were similar to humans in another key aspect:

“Unlike other species, but like humans, dolphins did not appear to have a strong Dominance domain. The overlap in personality structure between dolphins and other species suggests that selective pressures, such as those related to group structure, terrestrial lifestyles, morphology, and social learning or tool use are not necessary for particular domains to evolve within a species,” the researchers write.

Dolphins are more like us than we thought

“We’ve known for some time that dolphins are similar to us in other respects – for instance, you can just watch dolphins on television and see they’re very obviously smart and social,” Morton said. “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.”

The fact that dolphins have personality traits related to curiosity and sociability (specifically openness), and a trait that is a blend of extraversion and agreeableness, is striking. This dolphin personality trait exists although dolphins have evolved in a completely different environment from primates. In fact, the last common ancestor of dolphins and primates lived around 95 million years ago.

Did these personality traits exist back then, during what was still the age of the dinosaurs? It seems rather unlikely. More likely, researchers suspect, these personality traits emerge from selective pressure and group dynamics that are associated with intelligence.

“The overlap in personality structure between dolphins and other species suggests that selective pressures, such as those related to group structure, terrestrial lifestyles, morphology, and social learning or tool use are not necessary for particular domains to evolve within a species.”

These findings suggest that personality traits are not unique to land-dwelling species. Instead, they emerge in intelligent, socially complex organisms, irrespective of their habitats. Do other intelligent creatures share the dolphin’s personality traits? Quite possibly. But ultimately, understanding dolphin personalities also broadens our comprehension of human personality and social organization as well.

The parallels between humans and dolphins should prompt us to rethink our relationship with nature — especially as we acknowledge our shared characteristics with other forms of intelligent life. This study is more than a scientific curiosity. It’s a journey of self-discovery, helping us understand human personality and intelligence in a wider context of life.

While the study didn’t directly look at insights on how the human personality traits might have evolved, for the researchers it’s just a first step in beginning to understand the full spectrum of traits exhibited by dolphins.

Further studies will help to better appreciate the species living in our oceans and will lead to a better understanding of human personality, they added.

The study was published in the Journal of Comparative Psychology.