Corvids reveal highly-developed communication abilities
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.
Other examples of animal intelligence include gorillas that can communicate in sign language, dolphins using tools and having cultural elements and elephants co-operating to solve physics puzzles. Animals even suffer the same psychological effects as humans, as shown with the 5% of American military dogs suffering from post-traumatic stress disorder.
Altogether, this suggests that many animals may be far more intelligent than they are often given credit for.