Each shark has a distinct personality and just like humans, these predators of the sea can either be social or solitary, findings of a new study suggest.

Certain animals are known to have their own unique characteristics but individual personalities have not been associated with sharks before. A team of researchers led by scientists from the University of Exeter and the Marine Biological Association of the UK (MBA) demonstrated that the fearsome hunters of the ocean each have its own personality traits.

For the new study published in the journal Behavioural Ecology and Sociobiology on Oct. 2, David Jacoby, from the Institute of Zoology in London, UK, and colleagues monitored the social interactions of ten groups of small-spotted catshark (Scyliorhinus canicula) in large tanks at the Marine Biological Association of the UK in Plymouth.

The tanks contained tree different types of habitat. Some had plenty of rocks and other features while some had a simpler environmental structure. The researchers noticed that although the number and size of the sharks' subgroups were frequently changed between environments, the sharks that were likely to form big groups continued to do so regardless of the environment they were in.

The solitary-type sharks, on the other hand, tend to mingle in smaller group or remained alone. Jacobson said that these sharks were likely to camouflage their skin color with that of the gravel in the tank, behavior comparable to that of shy people who tend to stay near a wall while other people socialize with others.

"We quantify repeatability in sharks by demonstrating that despite changes in aggregation measured at the group level, the social network position of individuals is consistent across treatments," the researchers wrote.

William Hughes, an expert on animal behavior from the University of Sussex said that the experiment with the sharks is comparable to observing a group of people. Some individuals tend to socialize and some tend to be on their own or to only mingle with a few individuals regardless whether they are in a bar or at work.

Small catsharks in the wild are susceptible to getting hunted by larger fish, explained Darren Croft, from the University of Exeter. He said that the anti-predatory strategies of these sharks have probably evolved resulting to these personalities.

"We define personality as a repeatable behavior across time and contexts," Croft said. "What is interesting is that these behaviors differ consistently among individuals."