London, April 27 (IANS) An international team of researchers has found that despite having much smaller brains ravens are as clever as chimpanzees.
The findings indicate that rather than the brain size, neuronal density and structure of the birds' brains play an important role vis-a-vis their intelligence.
"Absolute brain size is not the whole story. We found that corvid birds performed as well as the great apes, despite having much smaller brains," said Can Kabadayi, doctoral student at Lund University in Sweden.
Intelligence is difficult to test, but one aspect of being clever is inhibitory control, and the ability to override animal impulses and choose a more rational behaviour.
The team analysed ravens, jackdaws and New Caledonian crows to better understand their inhibitory control.
The performance of the jackdaws and the crows came very close to 100 percent, comparable to a performance by bonobos and gorillas.
"This shows that bird brains are quite efficient, despite having a smaller absolute brain size. As indicated by the study, there might be other factors apart from absolute brain size that are important for intelligence, such as neuronal density," Kabadayi explained.
The team first trained the birds to obtain a treat in an opaque tube with a hole at each end. Then they repeated the test with a transparent tube.
The animal impulse would naturally be to go straight for the tube as they saw the food.
However, all of the ravens chose to enter the tube from the ends in every try.
"There is still so much we need to understand and learn about the relationship between intelligence and brain size, as well as the structure of a bird's brain. But this study clearly shows that bird brains are not simply birdbrains after all," the researchers concluded.
