Toucans range in size from 18 to 63 cm (7 to 25 in). A bit bigger than a crow, their body is short and thick and the tail is rounded. The tail varies in length from half the length to the whole length of the body. The neck is short and thick while at the base of the head is a huge, brightly-colored beak that measures in some large species, more than half the length of the body. A toucan's tongue is long, narrow, and singularly frayed on each side, adding to its sensibility as an organ of taste.

Toucans are frugivorous (fruit-eating), but will take insects and other small prey such as small lizards. However, many other birds consume these foods without the giant bill to help them. So what is the function of the beak in feeding? One likely use is to specialize on prey such as nestlings and bats in treeholes. In this view, the beak is an adaptation to allows the bird to reach deep into the treehole and thereby access food unavailable to birds that would otherwise compete for similar food reasources.