Rhinoceros Hornbill Buceros rhinoceros Classification ... - Denver Zoo

Rhinoceros Hornbill
Buceros rhinoceros
Classification
The hornbills’ closet relatives are kingfishers, rollers and bee-eaters.
Class: Aves
Order: Coraciiformes
Family: Bucerotidae
Genus: Buceros
Species: rhinoceros
Distribution
Rhinoceros hornbills are found in Malaysia, Sumatra, Borneo and southern Thailand.
Habitat
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.
Diet
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.
Adaptations
Seed Dispersers
Rhinoceros hornbills are important agents for dispersal of figs and other large fruits because they
eat 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.
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.