Head to head
Hornbill vs Toucan
Hornbills and toucans are the textbook example of convergent evolution in birds: two unrelated families that independently evolved an oversized bill for reaching and handling fruit in the rainforest canopy, one in the Old World and one in the New.
| Hornbill | Toucan | |
|---|---|---|
| Family | Bucerotidae, ~60 species | Ramphastidae, ~40 species |
| Where | Africa and tropical Asia | Central and South America only |
| Closest relatives | Hoopoes and wood hoopoes | Woodpeckers and barbets |
| The bill | Heavier, usually topped by a hollow casque | Very light bony foam; also sheds body heat |
| Neck | First two vertebrae fused to carry the bill | Normal |
| Nesting | Female sealed inside a tree hole with mud | Open tree cavity; no sealing |
| Eyelashes | Yes, prominent modified feathers | No |
| Ground species | Ground hornbills, large and carnivorous | None; all arboreal |
Hornbill vs Toucan: common questions
Are hornbills and toucans related?
No, only distantly, as both are birds. They look alike because both evolved a giant bill to fill the same role, a fruit-eating canopy bird that needs to reach food on branches too thin to perch on, but they did so independently on different continents. Toucans belong to the same order as woodpeckers and are confined to the Americas. Hornbills are an Old World family whose nearest living relatives are the hoopoes. Their resemblance is one of the most cited cases of convergent evolution among birds, alongside the way Old World and New World vultures came to look alike.
Which has the bigger bill, a hornbill or a toucan?
Relative to body size, the toucan, whose bill can be a third of its total length, the largest bill-to-body ratio of any bird. In absolute terms the largest hornbills, such as the great hornbill and the ground hornbills, are much bigger birds overall and have longer, heavier bills with a large casque on top. The toucan solved the weight problem by making its bill almost hollow, a lattice of thin bone under keratin, so it stays light despite the size. The hornbill bill is denser and needs the support of fused neck vertebrae, and in the helmeted hornbill the front of the casque is a solid block of keratin.
Do both birds wall up their nests?
Only hornbills. In almost all hornbill species the female enters a natural tree cavity and then, with help from the male, seals the entrance with mud, droppings, and food remains until just a narrow slit is left. She stays inside for the whole nesting period, from about six weeks to four months, moulting her flight feathers, while the male passes food in through the slit. It is a defence against snakes and other nest predators. Toucans use unlined open tree holes, often old woodpecker holes, and both parents come and go freely, so the walled-in nest is a hornbill signature with no toucan equivalent.