Denver Zoo Map

Rhinoceros Hornbill


Class: Aves
Order: Coraciiformes
Family: Bucerotidae
Genus: Buceros
Species: rhinoceros


Fun Facts

  • When flying, the wings of the hornbill make a loud humming sound that can be heard up to 65 feet away.
  • Males have red eyes and females have white eyes.
  • Hornbills have very long eyelashes that protect their eyes from injury. The eyelashes are actually modified feathers.
  • Hornbills are the only birds that have the first two neck vertebrae fused together. Along with strong neck muscles, the fusion of the vertebrae helps support the weight of their large bill and casque.
  • While enclosed in the nest chamber, the female undergoes a simultaneous molt of all flight and tail feathers. She grows new feathers by the time she emerges from the nest.



Rhinoceros hornbills are found in Malaysia, Sumatra, Borneo and southern Thailand.


This species inhabits dense lowland forests with large trees suitable for nesting sites.

Physical Description

Rhinoceros hornbills are two and a half to three feet (75-90 cm) long; males are slightly larger than females.

They weigh four and a half to six and a half pounds (2.0-3.0 kg).

Feathers on the head, back, wings and breast are black with white feathers on the belly and a white tail with a black band through the middle.

They have a long curved bill with a casque on top. The bill and casque are ivory white tinged with yellow, with bright red coloring at the rear end of the casque.


What Does It Eat?

In the wild: Fruits, nuts, small animals including lizards and birds, and some insects.
At the zoo: Chopped apples, bananas, yams, grapes, bird pellets, bird of prey diet, and mice.

What Eats It?

The young rhinoceros hornbills are threatened by monkeys and snakes.

Social Organization

Rhinoceros hornbills live in monogamous pairs but they will congregate in groups at trees where food is abundant.

Life Cycle

A month or more before mating, the male hornbill begins courting the female by bringing her food. Together the male and female select a nest hole high up in a tree and begin preparing the nest by plastering up the hole with mud and droppings. The male plasters the hole from outside and the female works from inside until only a small slit remains, creating a predator-proof nest. The female lays two to three white eggs and remains enclosed in the nest for three months incubating the eggs and caring for the chicks while the male delivers food to her and to the chicks. The chicks hatch after 39-45 days. Once the chicks have their first feathers, the female breaks out of the nest chamber and joins the male in providing food for the young. The chicks remain in the nest for about 80 days and then break through the opening. Rhinoceros hornbills are not sexually mature until they are about four years old. Lifespan in the wild is around 30 years and this species can live up to 33 years in captivity.


Seed Dispersers

Rhinoceros hornbills are important agents for dispersal of figs and other large fruits because theyeat the entire fruit, including the seed, and then fly long distances before dispersing the seeds in their feces.

Multifunctional Bill

Their strong bill is a functional adaptation with many uses. Both males and females use their bills like trowels to plaster up the nest hole. The long bill enables these birds to reach fruit on the outer branches of forest trees. The tip of the bill is used like a finger to pluck fruit from trees and the notched edge of the bill is used for grasping food. They toss food up in the air, catch it in the bill and swallow it whole. The bill is also used for defense against enemies.

Distinctive Casque

The distinctive casque on top of their bill looks heavy and cumbersome. Composed of keratin overlying bony support, the casque is very strong and relatively lightweight. The casque is used in recognizing the age, sex and species of the hornbill. It also acts like a resonating chamber that amplifies their loud squawks.

Conservation Connection

IUCN Status: Near Threatened.
Rhinoceros hornbills are listed as near threatened due to loss of habitat, poaching for their feathers and hunting for food.

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