London: Don't underestimate the intelligence of crows just because they are birds, as a new study has found that they possess the seemingly human ability to distinguish between symbols representing different quantities.

In a series of experiments, a team at the Utsunomiya University in Japan found the birds successfully selected containers containing the highest quantity of food via numbers marked on the lid.

According to Professor Shoei Sugita, who led the study, the findings suggested that crows possess the same numerical cognition ability as humans, a newspaper reported.

Eight jungle crows took part in the experiments, during which two containers marked with "two" and "five" numerical symbols on the lid were placed in a cage.

Food was contained only in the container marked "five" but the crows were able to pick the correct box with 70 percent success rate.
In further experiments, non-numerical symbols of a variety shapes and sizes as well as additional numbers between two and eight were also used to gauge the crows' skills.

The results found that the crows achieved a 70 to 90 percent success rate choosing the correct container holding food during 19 out of the 20 different symbol combination experiments.

The findings, published in the international journal Animal Behaviour, confirmed for the first time that crows can distinguish between quantities of items, Prof Sugita said.

"We want to reveal more about the unknown intelligence of crows," he was quoted as saying.

The symbols study is the latest in a host of experiments focusing on crows. Last year, the scientists from the same university reported that crows were also capable of distinguishing between the faces of men and women.

(Agencies)