Sharks are apparently capable of learning when not to bother pursuing prey because it's unlikely to lead to a meal.
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The Port Jackson, a bullhead species endemic to southern Australia, has an astute ability to realise when the smell of its quarry doesn't represent feeding time, researchers say.
A study conducted at Flinders and Macquarie universities shows the shark's response to the smell of food declines if it is not sufficiently rewarded by the promise of eating.
The result suggests it can purposely avoid wasting time and energy.
The behaviours of three groups of captive Port Jackson sharks were observed in relation to different reward frequencies.
The first was automatically granted food upon reaching a target, the second was fed every other day and the third wasn't rewarded at all.
The group of sharks always rewarded quickly learned the task and became better and faster at reaching the target.
However the opposite was true for the unrewarded sharks, who exhibited less response to the smell and stimulus of potential food and declined to leave their starting position.
"Our study revealed that ... the learnt response diminishes when reward frequency is decreased and even disappears when no reward is provided," said lead author PhD student Dennis Heinrich.
"The observed decline in response to a repeated stimulus, or habituation, may act as a driver of optimal foraging strategies, enabling sharks to quickly abandon low-yielding patches for more productive sites."
It's hoped the finding will hasten understanding of sharks' evolutionary ability but also assess their response to tourism activities that use food or smell to attract them to the proximity of visitors.
Senior author and marine ecologist Charlie Huveneers says there's still a lot which is unknown.
"The knowledge gained from this study can help account for learnt behaviours and habituation when managing wildlife tourism moving forward," Professor Huveneers said.
"A balance needs to be found between attracting sharks for tourism and minimising behavioural response and possible learnt behaviours."
The next step will be to similarly observe other shark species like great whites.
Australian Associated Press
