In a comparison of size, crows are generally smaller than ravens. However, there are large crows and small ravens. Hence, the best way to distinguish the two is by looking at the appearance of their beaks, wings and tails.
Crows are more social and inhabit human-populated areas such as cities. Ravens prefer wilder areas and the countryside, where there are fewer people.
Crows tend to socialize in groups, and a group of crows is called a murder. Ravens prefer to be solitary or travel in pairs. Crows help each other raise babies, whereas ravens do not.
“Crow” refers to any bird of the genus Corvus which includes crows, ravens, jays and magpies. “Raven” is the type species of the genus Corvus, having a larger distribution over the Northern Hemisphere