People, including scientists, have wondered for ages how intelligent crows are; alternately, under what conditions crows (or other animals) ever use tools as humans do. A recent video, shot at long distance in an uncontrolled situation, shows striking evidence of this. A crow finds a jar lid and takes it up to a snowy rooftop, where it stands on the lid and sleds down the roof. It then picks up the lid, returns to the rooftop, and sleds down again. Repeatedly.
When people think of the most intelligent animals other than humans, the first contenders are the dolphins and great apes. A less-obvious one may be birds of the family Corvidae, containing both crows and ravens. This was suggested when researchers at Oxford found crows are able to make specific tools, a feat never before seen in other animals.
More recently, ravens have been shown to direct other individuals' attention through gestural communication; the first time this has been seen outside of the primates. In primates, such gestures are rarely seen in the wild. Why wild ravens show this behaviour more commonly is unknown, but it is thought by some to be the foundation of language.