The largest member of the crow family (with a wingspan of 46-56 inches), the raven is generally recognized as the most intelligent bird in the world and has adapted to a range of habitats. It differs from the crow in several ways: larger overall size, longer and thinner wings, wedge-shaped tail, longer thicker beak, and beard-like throat feathers. It produces a range of sounds from croaks to shrill calls, and can, to some extent, mimic the calls of other birds as well. And, unlike crows, ravens mate for life.