Do Sharks Really Have Personalities?

Media reports have called them the “tigers of the sea” and “white death,” striking potential prey with the “power of a horse.” Such descriptions are fearsome enough, but it’s the great white shark’s purported appetite for human flesh that sends chills skittering up spines. A 1916 article in the Richmond Times-Dispatch, printed just after the still-famous string of shark-related deaths that year, came to a truly creepy conclusion: Those who believe that the great white’s propensity to dine on humans is real and steadily increasing “have the weight of evidence on their side.”

Thanks to the movie Jaws, the great white’s reputation as a ruthless man-eater pervades to this day. So you can’t be blamed for being slightly concerned if you took a quiz claiming to match your personality with a shark’s, put together by the Discovery Channel, and found out that you are a great white. Sure, you may indeed be “curious yet cautious” and “aggressive but also recessive;” people may be “dangerously intrigued” by you. But does your personality really match that of such a loathed creature? Can an entire species of sharks be generalized in that way?

Jean Sebastien Finger, a biologist at the Bimini Biological Field Station in the Bahamas may have answers. For a little over a year, Finger has been trying to find out whether sharks have personalities. Personality, by its very name, seems to apply only to a person, e.g., a human. But can a shark actually be shy? Social? A risk-taker? Fierce or mellow?

Though Finger is the first, to his knowledge, to study sharks in this way, he is not alone among animal behaviorists. His work fits with a growing field of research investigating what scientists call “behavioral syndromes,” or ways of acting that differ from one individual to another but are consistent across time and situation. It turns out scientists are finding personality in a whole range of species, sharks now included.

The basic idea that nonhuman animals have personality isn’t all that new. In the 1920s in Conditioned Reflexes, Ivan Pavlov describes his observations of different behavioral responses in dogs “depending on the type of nervous system of the animal.” And in 1938, an American psychologist named Meredith P. Crawford developed a behavior rating scale for young chimpanzees, publishing the work in the Journal of Comparative Psychology. Jane Goodall was a bit more personal, noting in the memoir Through a Window, that the personality of one chimp named Passion was as different from another chimp’s “as chalk from cheese.”

Yet only recently has scientific opinion shifted beyond viewing this variation as meaningless noise. Researchers now want to quantify individual variation and figure out why it exists. For example, scientific observers are increasingly coming to the realization that animals don’t always behave in the best way in a given situation, says Alexander Weiss, a psychologist at the University of Edinburgh who studies evolution of personality. An animal may not go off on its own to look for food, even though that seems like the best choice. “They are behaving suboptimally,” Weiss says, “what is underlying that?”

Imagining primates and even pets with their own personalities isn’t so hard. But some of the most fascinating work stars less predictable animals–birds, fish, hermit crabs and spiders, among others. Unlike the shark quiz offered by the Discovery Channel, the studies distinguish not one species from the next, but individuals within a species.

Finger’s species of choice is the lemon shark, and with good reason. These sharks are the lab mice of the sea. Scientists know a ton about the biology of lemon sharks–they are easy to capture and handle, and they are amenable to captivity. What’s more, Finger works with juveniles, which measure a meter or less in length.

After catching and tagging these sharks in the shallow waters of Bimini, about 60 miles east of Miami, Finger and his colleagues run a battery of tests in experimental pools. In a test looking for sociability, they allow the sharks to swim around together for about 20 minutes, documenting every 30 seconds whether a shark is interacting with its peers. “If you see two sharks following each other, that is typical social behavior,” says Finger. “It’s very similar to humans in the sense that some people will be in groups more often than other people.” In another test looking for an interest in novelty, Finger and his team put sharks, one at a time, in a 40-by-20 foot pen that the sharks have never experienced. The team documented how much each shark explored the pen.

In both cases, sharks are tested again after a week and after six months (returning to their natural habitat during the longer interim, only to be caught once again). The repetition allows the researchers to test for consistency. Preliminary results presented in July in Albuquerque, New Mexico, at the Joint Meeting of Ichthyologists and Herpetologists show that individual lemon sharks do have different degrees of sociability and novelty-seeking. “They are not machines, they have personality,” Finger says.

What’s more, initial data hint at a trade-off: Sharks more interested in novelty tend to be less social, and vice versa. Finger suspects that animals that have the safety of a group take fewer risks. Novelty-seekers venture off on their own and, though more prone to danger, they also don’t have to share the food they find with others. It’s sort of how the risk-takers and game-changers in human societies aren’t always so good at playing well with others.

In time, scientists hope to compare personality data from a range of species to try to understand why animals, including people, have personality and how it evolved. Personality, and even a mix of personalities within a group, may turn out to have huge consequences for survival. “We find in the human literature that personality is massively important for things like work satisfaction, marital stability, how long we live, whether we get heart attacks,” Weiss says.

Until then, Finger’s big message is that “you can’t generalize behavior of one individual to a species.” Even if a species as a whole tends to be more aggressive than another, some individuals within that species could still be pretty mellow.

So although your concept of self isn’t likely to be wrapped up in an online quiz, you may find comfort in Finger’s words. Maybe you are a great white, but not every great white is the same.