Researchers from two of Australia’s universities have uncovered some lazy sharks. Well, sharks that don’t bother attempting to kill if they aren’t going to be rewarded by a snack. This research tells me I have more in common with a shark than I thought (obviously not the killing part).
This research from ecologists at Flinders University and Macquarie University says sharks in their test area (Port Jackson) have learned to realise when the smell of natural prey doesn’t lead to a feeding opportunity.
The ecologists say a sharks’ response to the smell of food declined if not sufficiently rewarded by the promise of eating. They reckon this suggests sharks can learn to avoid wasting time and energy on inaccessible food sources.
The researchers say the results, published in Animal Behaviour, are a catalyst for better understanding sharks’ evolutionary ability to learn and their response to tourism that uses food or smell to attract sharks to the proximity of visitors.
The researchers used three groups of captive Port Jackson sharks to study their response to smell across different reward frequencies – the first group was rewarded with food every time they reached a target, the second was only rewarded every other day and the third group was never rewarded.
The group of sharks that was always rewarded quickly learnt the task and became better and faster at reaching the target. However, the opposite was true for the un-rewarded sharks. The ecologists said in this bunch of sharks, they observed a reduction of their natural response to the smell and stimulus of potential food, with sharks no longer leaving their starting position.
“Our study revealed that while shark behaviour can change when frequently rewarded with food, the learnt response diminishes when reward frequency is decreased and even disappears when no reward is provided,” says lead author of the study 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 foraging patches in search of more productive sites.”
There’s still a lot we don’t know about shark behaviour, though this research is a start.