The Red-breasted Toucan is the smallest species of Ramphastos. This also is the most southern species of toucan, occuring from east central Brazil south to eastern Paraguay and northeastern Argentina. In parts of its range, in southeastern Brazil, the Red-breasted Toucan overlaps geographically with a distinctive subspecies (ariel) of Channel-billed Toucan (Ramphastos vitellinus). Both of these toucans are superficially similar, with an orange throat and breast, red belly and tail coverts, and red orbital skin. But they easily can be distinguished by bill color: mostly black in Channel-billed, and mostly light green in Red-breasted. These two species also have similar "croaking" vocalizations, although the calls of Red-breasted are more raucous. The two species tend to segregate by elevation, with Red-breasted in montane forests and Channel-billed restricted to the lowlands.