We've all taken online personality tests which may or may not be a true reflection, but when it comes to figuring out the nature of one shark species, scientists have found a foolproof way of finding out -- hug them.
Researchers from Macquarie University in New South Wales have developed a test to assess individual personalities of Port Jackson sharks, particularly about how docile they are.
It's an animal known for its meek manner, which a New Zealand shark expert rated as less dangerous than a blue cod.
(Supplied)
The test, done in the wild, involved researchers tucking the sharks under their arm and gauging the reaction as they are taken toward the surface.
The sharks were ranked on a scale of one to three based on their immediate response to being captured.
A score of one meant "complete immobility" and three a "strong reaction and attempt to free themselves".
Port Jackson sharks are among the most numerous around the southern east coast of Australia (Supplied)
They say the test was effective and repeated inter-individual docility was seen.
Of the 73 sharks tested, the study showed male sharks were less docile than females, potentially to do with the role each sex has in mating.
The researchers say more work needs to be done to clarify the mechanisms behind different personality traits of invertebrates.
Each shark had a different, but consistent reaction to being handled (Supplied)
Another recent study from the same researchers, published in the Journal of Fish Biology, tested the animals' ability to cope with stress and their boldness in a captive environment.
It found individual sharks had distinct and consistent responses when exposed to unfamiliar environments.
Their boldness, a measurement of risk-taking, was measured by putting them into an unfamiliar tank with a shelter and timing how long it took them to explore the new habitat.
The second test looked at how the sharks handled stress where they were taken out of water and put back into it -- they measured how long it took them to recover.
Results showed repeated and consistent behaviour, indicating hard-wired behaviours rather than one-off reactions.
Port Jackson sharks at Taronga Zoo (Supplied)
Associate professor Culum Brown says the results are more than likely be applicable to all shark species and all vertebrates.
"My feeling is all shark species have individual personalities; that they're going to respond uniquely in different contexts consistently.
"When you catch a shark, a shark is not a shark is not a shark. They're going to respond to handling stress, or the stress of being on a long-line or caught in a net, all of them are going to do that differently."
He hoped the studies would "dispel myths" about sharks, which can get a bad rap in the media, particularly following attacks on people.
The Port Jackson shark was chosen for the study partly because of its nature: "they're like puppy dogs", but also because there are so many of them compared to white shark species.
"It would take weeks to find one, to catch one and process it whereas we can do 100-and-something in a day if we're working on PJs."
He says personality tests have been done on animals for years, including working animals, seeing eye dogs and horses in the army -- they're chosen based on their temperament.
The findings could be significant for managing sharks in the wild, Prof Brown says.
"If you're going to go drum-lining for a certain shark, there are only a certain number who will take the bait and there's only going to be a certain proportion of those who will react well to that."
Department of Conservation shark scientist Clinton Duffy says the species, which has flat teeth to crush shellfish, are "incredibly docile".
The Port Jackson shark's teeth are developed for eating shellfish, not biting (C Gervais)
"It spends most of its day in piles on top of each other. These things you can swim [on and] lay on top of."
He thought the hugging technique was "out there", but the Port Jackson shark was an animal that can be manipulated easily and safely in the field.
When asked if it posed any danger to humans, Mr Duffy replies: "Hell no, these are the most innocuous critters out".
"I'd rate a blue cod more dangerous than those things. I've been bitten by a blue cod, I couldn't imagine being bitten by a Port Jackson shark."
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