Sharks have long been thought of as soulless killing machines, but the fascinating creatures are jazzier than most people ever gave them credit for. Or, at the very least, they learned to appreciate jazz music when presented with treats! Australian researchers are hoping to turn the tide on shark perceptions and research, starting with a study published in an April 2018 issue of the journal Animal Cognition.
"Sharks are severely understudied, especially with regards to their learning abilities. One reason is that it is often not feasible or less practical, but also because for a long time we had a very low opinion on them," explains lead researcher Catarina Vila Pouca, a Ph.D. student with the Macquarie University Fish Lab in Sydney, Australia, in an email interview.
The purpose of the study was to investigate learning abilities of sharks, particularly related to sound. Most underwater animals use sound to communicate, locate prey, navigate and orient themselves (Vila Pouca offers the sound of surf in reef areas as an example). Previously, sound use by bony fish and other aquatic mammals was studied, but little has been known about how sharks process these cues, other than some anecdotal evidence of sharks associating outboard motor noise with cage diving activities and baiting in fishing.
So, the researchers decided to test whether our sharp-toothed friends could learn to associate an artificial sound cue – in this case, a clip of a jazz song – with delivery of a food reward in a specific location. Only eight Port Jackson sharks were studied. Of those, five learned to go to a specific corner of the tank for a food reward when jazz music was played.
The researchers then conducted a follow-up experiment to see if the sharks could differentiate between jazz and classical music, or if all music was one and the same to them. "If the jazz song played, they would go to the same feeding area. If the classical music played, they would go to an opposite area. None of the sharks was able to learn this new task," Vila Pouca notes. "The interesting finding is that they didn't keep going to the feeding area they had previously learnt, so they knew there was something different in the task and were trying to figure out the new rule." These results are expected to be pertinent to all variety of shark breeds.
However, don't expect sharks to pick up a trumpet anytime soon. Classical and jazz genres were simply selected because a few other studies of koi carp and pigeons had already used them, so the team followed their lead in hopes of comparing results.
"We did not exactly test for a preference between the genres (I think the message got a bit distorted now with so many news outlets picking [the study] up)," Vila Pouca explains. "Any artificial sound is new to them and has no ecological relevance, so using boat noise or music to test the hypothesis is very similar."
This study is one of the first steps toward improving conservation efforts for sharks. Vila Pouca notes that studies like hers are very valuable for understanding the types of cues and signals that are important to sharks, as well as the ways they use them to increase survival odds — for instance for finding food and shelter.
"We also hope our research can help people empathise more with sharks and understand how fantastic and complex animals they are – this is especially important in present times, with heavy overfishing, finning and culling practices, where a strong favourable public opinion can contribute to good management and conservation of shark populations."