Changing Planet

Do Lemurs Have Personalities?

A gray mouse lemur perches on a fingertip. Photograph from A&J Visage/Alamy
How individual gray mouse lemurs, like this one perched on a finger, approach new objects may provide a hint about how well they would survive environmental changes. Photograph from A&J Visage/Alamy

Lemurs have identifiable personality traits that are consistent from situation to situation, and those tendencies may have evolutionary implications, according to a new study conducted at the Duke Lemur Center.

Ecologist Jennifer Verdolin tested captive gray mouse lemurs, small, large-eyed primates native to Madagascar’s forests, to see how they reacted to unfamiliar objects and foods.

She placed items such as a tiny chair, a wooden ladybug, and a stuffed toy frog, as well as new foods such as mango and papaya, into the animals’ enclosures. After classifying individual lemurs’ reactions, she monitored how agitated they became during routine handling for cage cleaning and health measurements.

Bolder lemurs—those who spent more time interacting with the new objects—were less likely to urinate, defecate, bite, or otherwise protest when handled, compared with their counterparts who had avoided the unfamiliar objects. (The study didn’t find a measurable difference in their reactions to the new foods, perhaps a sign that the lemurs did not perceive them as unusual.)

Verdolin explained that these protest reactions likely reflect fear, and that the bolder lemurs responded with more confidence in the stressful situations. Bold lemurs may be more likely than shy ones to adapt to uncertain or changing environmental conditions, and boldness and shyness may run in families.

“There’s actually evidence of heritability in these traits,” Verdolin explained, which would have implications for the evolution of the species.

“Of course natural selection can’t work on something that’s not heritable,” said Verdolin.

Since the time of her study, the lemurs have had offspring.

Up next? Verdolin says she would love to return to explore whether the traits have been passed down.

“If you have a bold mother, are you going to be bold too?” she asked.

Three gray mouse lemurs peek out of a nook in their enclosure at the Duke Lemur Center. Photograph by David Haring, Duke Lemur Center

The idea of studying animal personalities has experienced a bit of a boom in the last decade, countering the prevailing tendency by animal researchers to treat individual variation in animals as statistical noise. Some work in the early 20th century with chimpanzees explored the idea of animal personalities, but research has really taken off since an influential paper on the subject was published in 2004.

Many scientists still shy away from even using the term personality when talking about animals, favoring the less anthropomorphizing term “behavioral syndromes.” But both terms refer to individual animals reacting in the same way under different circumstances. “I personally don’t have a problem with using the term personality,” Verdolin said.

Verdolin sees the recognition of animal personalities as key to our understanding of species. “We have to remember we can’t just blankly categorize an entire species as being one way,” she said.

—Brad Scriber

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Brad Scriber is the Deputy Research Director for National Geographic magazine, with an emphasis on researching energy topics. He also contributes to NG Daily News, the Great Energy Challenge, and Pop Omnivore. Follow @bradscriber on Twitter.
  • Glenda Kennedy

    Very interesting and entertaining article about Lemurs!

  • Padmanabhan Jaikumar

    Very interesting study

  • Erika Sandhu

    Thanks for information,it is very intresting!!

  • Ann

    I don’t think domestication introduced individual personalities, so if dogs and cats have unique personalities, it stands that other animals possess innate individual personality traits as well.

  • Heather

    Interesting, although I was under the impression a lot of people have accepted the idea of animals having different personalities. Dogs have been bred to have personalities that are compatible with people – suggesting inheritable behavior. It reminds me of that experiment with the foxes.

    “Belyaev, however, believed that the key factor selected for was not size or reproduction, but behavior—specifically amenability to domestication, or tamability. ”

    Not that this is a bad experiment or anything, I just assumed that it was accepted already that certain “behavioral syndromes” were biological and heritable in wild animals. I’m certainly not an expert though, ha.

  • Donald Sepanek

    You’ve discovered individual differences among Lemurs, now the scientific task becomes discovering the cause of these differences. Assuming causes such as “personality” or “heritability” does not answer the question – only future research can.

  • Roy D. Schickedanz

    I certainly hope that Lemurs have personalities, since all animal life is cognitive, needing to know it is at position A and what is needed is at Position B, ever linking cognition and mobility. The Duke Lemur Center only confirms the case against any Darwian notions of revelations…Roy D. Schickedanz

    PS Keep up the good work

  • Melissa Mark

    A very interesting study in an exciting and dynamic line of research! This area of research has many important implications for how organisms will respond to human driven changes in the environment, such as forest fragmentation or climate change. There is strong evidence for heritability of shy and bold behavioral traits in great tits, so it would not be surprising if heritable personality traits were found in other organisms.

  • Jennifer Verdolin

    Great to see a discussion going about animal personalities. Thought I would add a little to some of the comments that have been made.
    First, an interesting point about the ultimate reason for the existence of personality. It is true that how those personalities are expressed (e.g., bold vs. shy) is very different then why have personalities at all. Several studies have begun to explore this question. To do so one looks at survival/reproductive, or fitness, differences among individuals exhibiting different personality types. Research on great tits has shown that in certain environments bold or aggressive individuals have a competitive edge and do better. At the same time, change the conditions and shyer (slower to explore) birds did better, particularly when intense competition was unnecessary. This tells us that there is variation in personality types, but also that there are fitness consequences to different personalities, helping to explain why they matter. Given that there is a genetic component to behavior we can continue to look at heritability of personality and how the environment influences the genetic component. Work on great tits and other species has set the stage for more work in this area (see references below for more information).
    On how well accepted personalities in animals has been in the scientific community, I think that accepting that there are differences in degrees of domestication/tamability of animals is not the same as accepting personality. Personality implies a set of behavioral traits, and selective breeding of dogs based on an individual’s domestication/tamability reflects one axis of behavior that may make up a total personality. There are other traits (exploratory behavior, aggression towards same species, likelihood of forming routines, neophobic behavior, etc.) that may or may not be interconnected to tamability. This also can be related to underlying links among genes. For example, selecting for tamability may simultaneously alter genes that are linked to other behaviors in ways we are only beginning to understand. For me it has always been obvious that animals have individual behavioral differences and personalities, but measuring and quantifying those differences is the first step to trying to demonstrate scientifically that this is the case.

    Some references for those interested in the heritability of personality in animals:

    P.J. Drent et al. Repeatability and heritability of exploratory behaviour in great tits from the wild Animal Behaviour, 64 (2003), pp. 929–938

    K. van Oers et al. Realized heritability and repeatability of risk-taking behaviour in relation to avian personalities. Proceedings of the Royal Society, London. Series B, 271 (2003), pp. 65–73

  • Galloway Grumblefield

    Animal personality is an interesting area of science. I know people are quick to say, “We already knew that!”, but that doesn’t mean the parameters of behavior have actually been measured, which is the work part of scientific investigation.

  • tobes

    i want one give me !!!!! awww

  • Sandy

    So cute!

  • Jenna Taylor

    WOW I find this information so freaking INTERESTING, lemurs are my favorite animals!!!! Specially the grey mouse lemurs because they remind me of myself!!

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