Crows are as intelligent as CHILDREN: Study reveals birds are as clever as a seven-year-old human
- They are the only non-primate species known to make tools, such as prodding sticks and hooks, which they use to pick up out grubs
- New study has shown that the birds could worked out how to obtain floating food rewards by dropping heavy objects into water-filled tubes
Crows have a reasoning ability rivalling that of a human seven-year-old, research has shown.
Scientists came to the conclusion after subjecting six wild New Caledonian crows to a battery of tests designed to challenge their understanding of cause and effect.
Thetasks were all variations of the Aesop's fable in which a thirsty crow drops stones to raise the level of water in a pitcher.
Scroll Down for Video
Clever: The 'water displacement' tasks (pictured) were all variations of the Aesop's fable in which a thirsty crow drops stones to raise the level of water in a pitcher
In the 'water displacement task', crows worked out how to catch floating food rewards by dropping heavy objects into water-filled tubes.
They demonstrated an ability to drop sinking rather than floating objects, solid rather than hollow objects, to choose a high water level tube over one with low water level, and a water-filled tube over one filled with sand.
The crows failed on two more difficult tasks, however. One test required understanding of the width of the tube and the other involved displacing water in a U-shaped tube.
The programme shows 007 the crow completing the eight stage puzzle in approximately two-and-a-half minutes. The individual processes are detailed in this diagram
Nevertheless, the birds' understanding of the effects of volume displacement matched that of human children aged between five and seven, claimed the scientists.
Lead researcher Sarah Jelbert, from the University of Auckland, New Zealand, said: 'These results are striking as they highlight both the strengths and limits of the crows' understanding.
'In particular, the crows all failed a task which violated normal causal rules, but they could pass the other tasks, which suggests they were using some level of causal understanding when they were successful.'
New Caledonian crows, named after the Pacific islands where they live, are famous for their intelligence and inventiveness.
They are the only non-primate species known to fashion tools, such as prodding sticks and hooks, which they use to winkle out grubs from logs and branches.
Another recent study also seemed to support the problem-solving ability of the birds.
The experiment, which was devised by Dr Alex Taylor, a Lecturer in Evolutionary Psychology based at The University of Auckland, New Zealand, involved a wild crow which had learned to use individual props during three months of captivity.
It successfully managed to work out the order in which to use them to complete an eight stage puzzle in approximately two-and-a-half minutes and get an inaccessible treat. The animal was later released.
The findings appear in the latest issue of the online journal PLOS ONE.
Most watched News videos
- 15 years since daughter disappeared, mother questions investigation
- Emergency services on scene after gunmen ambush prison van in France
- Flash floods 'rip apart streets' in Herefordshire's Ross-on-Wye
- British tourists fight with each other in a Majorcan tourist resort
- Harry and Meghan spotted holding hands at polo match in Nigeria
- Moment brawl breaks out at British-run 'Fighting Cocks' pub in Spain
- Youths wield knife in daylight robbery attempt in Woolwich, London
- 'I will never be the same': Officer recalls sickening sex attack
- William sits in an Apache helicopter at the Army Aviation Centre
- Moment Prince Harry and Meghan Markle arrive at Lagos House Marina
- New Colonel-in-Chief Prince William dons army combats
- Boy mistakenly electrocutes his genitals in social media stunt