Nature's 5 smartest animal species

Most people might not know it but crows are legendary for their smarts. A 2004 study in the journal Science found that for their size, crows possess unusually big brains, which are proportionate to the chimpanzee brain. A few years earlier, New Caledonian crows were discovered to be on the same level as nonhuman primates when it came to tool-related cognitive capabilities.

In a celebrated case a few years ago, an Israeli man was targeted by a local crow in an apparent revenge attack. The bird's chick fell out of its nest and the man carried it outside of his backyard. It wasn't long before the crow had him in its eye sights, forcing the man to wear a helmet and carry a parasol for self protection. That kind of intelligence wasn't a fluke. Take a look at this 2008 talk at the Ted Conference given by Joshua Klein, who showed off an amazing video displaying how crows quickly adapt to their surroundings.

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