Crows can 'reason' about causes, a recent study finds

Tool-making crows have the ability to "reason", say scientists.

In an experiment, researchers found that crows were more likely to forage when they could attribute changes in their environment to a human presence.

This behaviour may suggest "complex cognition", according to a study published in the Proceedings of the National Academy of Sciences.

Until now the ability to make inferences based on causes has been attributed to humans but not animals.