Crows Are As Smart As A Seven-Year-Old Child, Researchers Find

Crows are as smart as an average five to seven-year-old human child, according to a new study. The research shows that the crow behavior described in a popular Aesop's fable is real and that crows actually understand water displacement.

Science has known for a long time that crows and other members of the corvid family are intelligent. Now, researchers at the University of Auckland found that New Caledonian crows, Corvus moneduloides, can solve the pitcher puzzle in Aesop's fable with reasoning abilities that are comparable to a seven-year old child.

The New Caledonian crows are known to be good at tool making. These birds are also good at solving problems.

In the Aesop's tale, a thirsty crow comes across a pitcher that has water in the bottom. The crow starts throwing pebbles in to the pitcher until the water reaches the mouth of the container.

For the study, researchers subjected six wild crows to 4-6 experiments that tested their causal understanding of water displacement. The experiments assessed whether crows dropped stones into water-filled tubes or sand-filled tubes. They found that the birds chose tubes with high level of water and heavier objects to drop than lighter ones.

The crows passed in most of the tests. However, they did poorly in tests that required understanding the width of the tube and getting water out of a U-shaped tube.

"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," said Jelbert from the University of Auckland, lead author of the study, according to a news release.

The study is published in the journal PLOS ONE.

Check a video below to see how the crows solved the test. (Courtesy New Scientist/ Youtube).

A previous study by University of Cambridge researchers had shown that rooks, which belong to the corvid family, can solve the basic water task described in the Aesop's fable.