Wisest crows take shortcut on crafting tools: study

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New research has shown how New Caledonian crows develop their foraging tools.

Scientists have marveled for years at the unusual ability of these specific crows – native to France's South Pacific territory of New Caledonia – when it comes to tool-making.

Now they have found that the wisest and oldest crows tend to take shortcuts as they craft plant branches into crochet-like hooks to help them snag insects. They employ a quick and dirty method rather than the most careful beak-driven approach employed by younger crows.

According to a study published in the journal Current Biology on Thursday, juvenile crows tended to make controlled cuts to plants and sticks using their bills, resulting in much deeper hooks.

Study says the wisest crows take shortcut on crafting tools. /Photo via Xinhua

Older birds often used the sloppier method of simply pulling off branches, leading to shallower hooks.

"I suspect that there are costs associated with making tools that have really deep hooks, and that experienced adults may be avoiding these costs," lead author Christian Rutz, a biology professor at the University of St. Andrews, told AFP.

"This could include the extra time and effort that may be required for making deep hooks."

Even though deep hooks tended to help crows get insects out of holes faster, they might not be best in all foraging contexts.

"For example, they may break more easily if they are being inserted into very tight holes or narrow crevices," Rutz explained.

Older birds often use the sloppier method of simply pulling off branches, leading to shallower hooks. /Photo via Xinhua

Although dolphins, elephants, chimpanzees and other birds have been found to use tools like the New Caledonian crows, making hooks is a realm of its own.

"From all we know it's only New Caledonian crows and humans that craft hooked tools in the wild," said Rutz.

"Hook innovation marks a major transition in human technological evolution, so these crows offer fantastic opportunities to examine how such tool designs may arise, and how technologies may gradually advance further."

Source(s): AFP