What is the largest toucan species, found in South American rainforests?

The largest toucan species found in South America is the toco toucan.

The toco toucan, Ramphastos toco, is instantly recognizable by its glossy black body, white throat and enormous orange bill tipped with black. It is the largest species in the toucan family, Ramphastidae. Despite its size, the bill is relatively lightweight because it is made of a thin, honeycombed structure covered by keratin.

Toco toucans range from the Guianas and northern Brazil southward through Bolivia, Paraguay and Brazil to northern Argentina and Uruguay. They are associated with rainforest edges, gallery forests, wetlands and the Brazilian cerrado, rather than only dense, continuous rainforest. Their diet is mainly fruit, supplemented by insects, eggs and small nestlings.

The huge bill is not simply a feeding tool. Blood vessels in it help the bird release heat, making the bill an important thermal radiator. Toco toucans nest in natural tree cavities and usually lay two to four eggs. Both parents incubate the eggs for about 17–18 days. Keel-billed, channel-billed and aracari toucans are striking relatives, but none is larger overall.