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Personality tests - for sharks



Macquarie University in Australia think that sharks have personalities. Behavioural ecologist, Culum Brown, conducted the first personality tests of wild sharks, revealing that they have distinct personalities (The Canberra Times, 27 May 2016). The results were published in the Journal of Fish Biology on 26 May 2016.

Associate Professor Brown conducted the personality tests on 17 wild Port Jackson sharks from eastern Australia. The Port Jackson shark is common, small, not dangerous, and easy to work with. They are benthic – their teeth are designed for crushing sea shells and crustaceans (crabs and lobsters). Therefore their teeth are not razor-sharp, and they are not designed for gripping and ripping human flesh. These traits made them suitable for testing. The sharks were 1.5 metres (5 feet) long and weighed up to 30 kilograms (66 pounds).

Brown conducted personality tests on two personality characteristics: boldness (whether the individual sharks took risks) and resilience to stress. Boldness was tested by releasing each shark into an unfamiliar environment, but in the safety of a cave. The researchers tested the time it took for each shark to emerge from the cave. Their actions and behaviours were recorded on four separate occasions for each shark. To test resilience to stress the researchers lifted each shark out of the water for one minute before returning them to the water. They did this twice for each shark. They recorded each shark’s movement and agitation (a stressed shark moves a lot), and the length of time taken for each shark to return to a normal state.

The results showed that smaller sharks were less bold than larger sharks – they were more shy. Smaller sharks were also more stressed than the larger sharks. The researchers expected male sharks to be bolder, and less stressed than females. In just about every animal that has ever been looked at, Brown said, males tend to be bolder than females. However, in the shark personality tests, there were no personality differences between the sexes. The researchers think it may be due to the small sample for the experiment.

Overall, the researchers noted that the sharks had individual traits with their own distinct way of responding to stress and unfamiliar environments.

Image of Port Jackson shark by Juliana Kadar.

http://www.canberratimes.com.au/technology/sci-tech/sharks-have-personalities--just-like-us-20160520-gp034k.html


MARTINA NICOLLS is the author of:- The Shortness of Life: A Mongolian Lament (2015), Liberia’s Deadest Ends (2012), Bardot’s Comet (2011), Kashmir on a Knife-Edge (2010) and The Sudan Curse (2009).
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