Sharks Have Personalities, Too

From gregarious and personable to shy and solitary, sharks have personalities too, according to a new study.

Personalities are known to exist in many animals, such as in dolphins, spiders, and even ants, but are usually defined by individual characteristics such as how exploratory, bold or aggressive an individual is. And even though sharks are often depicted as heartless eating machines, researchers from the University of Exeter have shown for the first time that these predators actually possess unique social personalities. This determines how they might interact with group mates in the wild.

Published in the journal Behavioral Ecology and Sociobiology, the research team looked for personality traits in juvenile small spotted catsharks by recording their social interactions with each other in groups under three different habitat types.

Small spotted catsharks (Scyliorhinus canicula) are found throughout the northeast Atlantic and Mediterranean, and group together by resting around and on top of one another on the bottom of the seafloor. Researchers monitored 10 groups of sharks in large tanks containing three habitats which differed in their level of structural complexity. And even though each environment changed, one thing stayed the same.

"We found that even though the sizes of the groups forming changed, socially well-connected individuals remained well-connected under each new habitat. In other words, their social network positions were repeated through time and across different habitats," Dr. David Jacoby, a behavioral ecologist who was involved in the study, said in a statement.

"These results were driven by different social preferences (i.e social/antisocial individuals) that appeared to reflect different strategies for staying safe," he explained. "Well-connected individuals formed conspicuous groups, while less social individuals tended to camouflage alone, matching their skin colour with the colour of the gravel substrate in the bottom of the tank."

Personality is defined as a repeated behavioral process no matter the time or situation. This is clearly demonstrated for the first time among individual sharks, thanks to these new findings. One researcher, Professor Darren Croft, suspects that certain personalities developed among the toothy predators as a way for young, vulnerable juvenile sharks to avoid becoming (pun intended) shark bait. But further research is needed to support that notion.