Biologists have confirmed that crows are incredibly adept at crafting tools from twigs - a revelation that could prompt a rewrite of textbooks on animal intelligence.
In 2002, a captive New Caledonian crow named Betty astonished University of Oxford scientists when she bent a piece of wire to form a hook in order to retrieve food from a tube.
At the time, it was assumed that Betty had exhibited surprisingly advanced problem-solving skills that were thought to demonstrate a previously unseen level of intelligence in a non-human animal.
However, a new study from researchers at the University of St Andrews has revealed that tool bending is actually a part of the wild crow species' natural repertoire, throwing doubt on Betty's presumed problem-solving skills.
In the study, wild-caught crows were provided with food hidden in wooden logs, along with their preferred plant material for making tools.
What the researchers were not expecting was 10 of the 18 birds to start vigorously bending twigs into tools, just like Betty had with the wire, even though bent tools were not required to solve this particular task.
"We couldn't believe our eyes," said Project leader Dr Christian Rutz.
"Most birds trapped sticks underfoot before bending the tool shaft by bill, but one also pushed tools against the logs to flex them, and another wedged them upright into holes before pulling the shaft sideways, just as Betty had done.
"It turns out, the twigs that wild crows select for making their tools are pliable."
The research raises the question of why the wild crows, which are native to the island of New Caledonia in the South Pacific, would bend their stick tools automatically.
"We believe a curved tool is advantageous, because the bird can position it in its bill so that the tool-tip is bang in the middle of the field of binocular vision. This should improve tool control during foraging," explained study co-author Dr James St Clair.
While the new findings suggest that Betty, who died in 2005, may have simply been following a familiar tool-making routine, rather than working the problem, they do not definitely rule out the possibility that the canny crow understood the task and came up with a solution.
In 2014, the brainy birds were beaten in an intelligence test by human babies, suggesting that they were not quite as smart as previously thought.
"New Caledonian crows are gifted tool users. The highly dexterous behaviour we observe in adult birds is the outcome of complex interactions between genetic predispositions and lifelong individual and social learning – a process that we don’t yet fully understand.
"In light of our new results, more experiments are needed to figure out what exactly these birds are capable of," cautioned Dr St Clair.
The study was published in the journal Royal Society Open Science.
This article was originally published by WIRED UK
