As anyone who has spent time with a pet is well aware, animals do indeed have individual personalities.    

Having been to Africa on several occasions and watching as troops of baboons crossed roads, inspected parked cars, and generally tried to ignore all the staring tourists, I've seen firsthand the amazing range of personality traits on display.  Along with assertive troop leaders, it's easy to see traits such as curiosity, shyness, extraversion, and the natural "hams" who have no problem entertaining humans with their antics.   With her own work with chimpanzees at Gombe National Park in Tanzania, Jane Goodall prefers to name the chimps she observes rather than assigning numbers like many other researchers.   She has also written extensively about the complex personality traits she has observed in her subjects, though many of her colleagues argue in favor of a more scientific approach.

Much of the research looking at personality in animals has focused on mammalian species (particularly primates) due to their complex brain and social behavior.  Still, researchers have also identified recognizable personality traits in non-mammal species as well, including reptiles, birds, and fish. Primarily though, researchers have focused on mammals due to the relative complexity of their nervous systems and the social structures that can make personality traits easier to identify.   Unfortunately, while we can always sit humans down to complete psychometric tests if we want to learn more about their personality, measuring personality in animals tends to be a bit more difficult.   

Up to now, studies looking at personality traits in non-human animal species have usually focused on two basic methods:

  • behavioral coding - by closely monitoring the behavior patterns of test animals, researchers can measure how frequent animals can engage in different behaviors and for how long.  For example, chimpanzee research often involves measuring different "behavioral styles" to see how chimps interact with another, i.e., aggressive vs. courtship behavior, play behavior, etc.    
  • trait rating -  people who are familiar with the animals being observed are then asked to rate them on a set of predefined traits or descriptive adjectives.  For example, a 1997 study of 100 chimpanzees across 12 U.S. zoos had observers using a rating instrument consisting of 43 adjectives (i.e., "playful", and "affectionate.")   

Most personality studies looking at animals have relied on behavioral coding since it can be used in a variety of different settings, including naturalistic settings (animals in the wild or in wildlife preserves where they can be observed at a distance). Still, trait rating has become increasingly popular in recent years despite largely focusing on animals in captivity.  In general, trait rating studies usually involve either a "bottom-up" approach using adjectives specific to the species being studied, or a "top-down" approach using personality instruments developed for other species (such as humans) and adapting them as needed.   

Given the popularity of the Five-Factor Model of personality (FFM) (openness, neuroticism, conscientiousness, extraversion, and agreeableness), it's hardly surprising that it has become popular with animal personality researchers. Among the different species in with FFM personality traits have been identified are horses, chimpanzees, cats, dogs, rabbits, hedgehogs, and ferrets, to name just a few.  In particular, extraversion, neuroticism, and agreeableness have been identified in numerous species and may be linked to emotional reactivity and basic physiology.    

But what about cetaceans (dolphins, whales, and porpoises)?   Given the size and complexity of their brains, dolphins and porpoises make exceptional research subjects and countless studies have provided amazing insights into their social behavior and their capacity for learning new tasks.  Still, in terms of personality traits, there is surprisingly little research available.  While researchers have identified individual differences in play behavior with different cetacean species, including the bottlenose dolphin (Tursiops truncatus) and the Atlantic spotted dolphin (Stenella frontalis), actual evidence for a personality structure similar to humans remains scarce.  At least, up to now.

A new research study published in the Journal of Comparative Psychology provides an intriguing glimpse into the inner life of a previously little-researched cetacean species:  the killer whale (Orcinus orca).  While classified as a toothed whale, orcas are actually a species of oceanic dolphins, though their size makes them remarkable predators.  Their popularity as exhibits in many marine parks also makes them ideal subjects for the kind of "top-down" personality research previously used with chimpanzees and other land-based mammals.   

With this in mind,  a team of researchers led by Yulan Ubea of the Universitat de Girona in Girona, Spain examined 24 orcas (13 females and 11 males) at different marine facilities including SeaWorld San Diego, SeaWorld Orlando, and Loro Parque in Tenerife, Spain. All but six of the orcas studied were born and raised in captivity and ranged in age from 3 to 29 years.

Using a personality rating tool previously developed for chimpanzee research, staff and researchers at the different facilities rated each orca on 38 adjectives (eg., playful, cheerful, etc.).  Since each rater had an average of five or more years of experience with each orca, they were considered to be sufficiently familiar with their subjects to make the ratings.  They were also asked to avoid discussing their ratings with other raters to prevent contamination.  Results showed a fairly strong agreement between raters on the 38 adjectives used in the study.   

Based on their findings, Ubea and his colleagues concluded that captive orcas show a personality structure very similar to what was reported in humans and chimpanzees. But there were some interesting differences as well.  Along with personality traits such as Extraversion, and Dominance, they also found a common personality factor which they labeled "Conscience-agreeableness" since it combined adjectives reflecting both Conscientiousness and Agreeableness in humans.  They also found a fourth factor which they labeled "Careful" based on adjectives such as "helpful", "prudent", and "responsible."  This factor appears unique to orcas since it was never reported in any other nonhuman animal species.

While this is just a preliminary study, these results do suggest an interesting convergence between land-based and seagoing mammals.  Not only do cetaceans show remarkable similarities with chimpanzees in terms of complex cognitive abilities but their encephalization quotient (EQ) measuring relative brain size compared to total body mass is similar as well (EQ is 2.3 compared to 2.6 for orcas).   They also display cooperative behavior as well as evidence for cultural learning much as chimpanzees do.  This includes different orca populations learning novel hunting strategies and even developing separate "dialects" in communicating.  

The study authors also acknowledge that there are significant limitations to their research, especially since these results are based on a small sample of orcas in captivity.  Whether the same traits observed in these particular animals correspond to what orcas might display in the wild is still a very open question.  Even among humans, there are significant cultural differences in personality traits and how they affect behavior so understanding how these traits apply to orcas will take much more research.  

As we learn more about fascinating cetacean species such as orcas and dolphins, we gain a better appreciation about how much we have in common with them.  With cetacean species becoming threatened in many parts of the world due to overfishing and pollution, we can only hope this appreciation doesn't come too late.

References

Úbeda, Y., Ortín, S., St. Leger, J., Llorente, M., & Almunia, J. (2018). Personality in captive killer whales (Orcinus orca): A rating approach based on the five-factor model. Journal of Comparative Psychology.

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