Despite gaining a reputation as terrors of the deep, sharks have been found to have different personalities much like humans do.
In a study featured in the Journal of Fish Biology, scientists from Macquarie University in Sydney, Australia discovered that Port Jackson sharks have shown evidence of being shy, while others seem a bit more risk-taking than the rest of their kind. Some sharks are even less able to handle stress than others.
Culum Brown, a behavioral ecologist from Macquarie and one of the authors of the study, explained that animals have distinct personalities similar to the way human beings do. While some personalities are developed based on what is encoded in the animals' genes, others are influenced by what they experience in life.
To find out more about the creatures' varying personalities, Brown and his colleague, Evan Byrnes, placed a group of sharks in different scenarios and recorded how they would react to stressful situations.
The researchers first assessed the sharks' propensity to take risks by introducing them to a new environment and observing how long it would take the animals to leave their shelter and explore their unfamiliar territory.
Brown and Byrnes also measured how the sharks would react to stress after having been transferred from one tank to another. They took note of how long it would take for the animals to recover from the constant movement.
After subjecting the animals to the same tests several times, the researchers found that individual sharks showed responses that remained consistent throughout the experiment. This suggests that the creatures had an inherent tendency to show a particular action in response to different situations.
Brown said the behavior of animals can be influenced by their personality traits, much like the behavior of humans.
As an example, he pointed to the personality trait of being aggressive, which is often considered as an emotional response to certain social situations.
Scientists have identified as many as 200 different animals that show evidence of having personalities, such as mammals, birds and fish. Most of these creatures show the personality trait of being bold, which they seem to apply at varying degrees to aspects of their lives such as foraging for food and reproducing.
The researchers note that there seems to be no particular set of traits that can be considered entirely beneficial or detrimental to individuals. As far as the evolution of creatures is concerned, individuals would benefit more if they have a wide range of personalities.
"Increasingly, behavioral ecologists recognize that it is unlikely that any particular behavioral type would do well across a wide variety of situations and contexts in the natural world," Brown said.
Photo: Leszek Leszczynski | Flickr