Scientific name:
Bucerotidae

Natural spread:
Africa, Asia

the 45 types of the rhinoceros-birds forms a well outlined group of the Racken screws ; in the appearance, they hardly resemble the other families. At the most narrowly relative, they are with the Wiedehopfen, that also have itself from the original Racken screws n abgespalten already very early. By no means, they are toucans with the neuweltlichen considering one of the woodpecker-birds to be confused, that also trained such a notably big beak.

Beak This often is bent with the rhinoceros-birds strongly downward and becomes, with exception of the type Tokos, from a horny protuberance (just the "rhinoceros") protrudes. Beak and horn are gigantic, with it however incredibly easily, exception: Helmet-bird, because they contain wide airspaces, that passed through to the stiffening only from thin bone-buckles (Trabekeln), is.

Spread The rhinoceros-birds are over the tropical and subtropical forest-areas and also steppe-areas of Africa, Südostasiens and Ostindiens, as far as to the Philippines and the Salomonen, spreads. Fossil findings of a primitive type (Geiseloceros robustus) point it out that earlier rhinoceros-birds, d. h. approximately 40 million years ago, also in Europe occurred. With exception of the ground-living in horn-ravens, the today living forms are tree-birds. Alone in Africa (south from the Sahara), 25 types live, 12 types are to be found in Malaysia.

Nutrition The food consists of fruits and berries in the most important thing that however the smaller types live also from big insects; with the ground-living in types, small vertebrates (Nager and reptiles) add on top of this. Since the tree-fruits (Z). B. Figs, often at the thin ends of the branches sits, the long beak is an essential help with the harvest.

Way of life With the eating, above all the African types join together to small troops, that form companies with other animals on the other hand. The white-mop of hair-horn-birds (Tropicranus albocristatus) Z. B. monkeys join in order to catch them through their noise of startled insects. This behavior is so typical that these birds are called (monkey-birds) also "Monkey Birds."

Shape, types The smallest rhinoceros-bird is the Zwergtoko (Tockus camurus) from Africa with a length of 37 cm, the biggest type, the doubles-horn-bird, Buceros bicornis against it becomes 130 cm big. The weight of the birds is between 290 g (Elstertoko, Tockus fasciatus) and 4 kg (Sudan-horn-raven, Bucorvus abessinicus). The form of the leg-colored, black or red beaks frequently is different with the sexes, the females also are somewhat smaller in general. The plumage is usually black, often also with metal-shine, but also gray or brown, with white drawings. However, the white plumage-parts are colored (these plumage-colors become as "cosmetic" or "adhesion-colors" marks) by the secretions of the Bürzeldrüse, that contain Karotinoide, sallow very soon. While the African types frequently look same, the sexes of the Asian types often differ in the plumage-coloring and in the showy bare skin-parts at the head and necks.

Flight-behavior In the flight, the rhinoceros-birds work very heavily. A row of slow, powerful flaps exchanges with short, sailing gliding from. Since the sub-wing-blankets don't go beyond the energy-feathers, a sound, that sounds like the puffing a steam-locomotive, originates through the wind-stream at the wings. The small Toko-Arten are however quiet and skillful planes, that insects can even catch in the flight.

Reproduction The brood-habits of the rhinoceros-birds are especially strikingly. All types are cave-breeders, and until on the ground-living in types, the female locks itself up into a tree-cave. To this, the entrance with mud, earth, excrement or other materials is walled up by both partners one brood-pair as far as on one small opening; the male works with it from outside, the female of interior. The masoned wall becomes so solid that the birds after the incubation have effort to break it again open. This whole time over can put the female through the narrow opening only its beak in order to take over those of the male of along-managed food.

The 1-6 eggs (the number is type-dependent) must be incubated for 28 days on average. Between the individual deposit of the eggs, however, 5-7 days can pass. Even if the boys slipped, they still require 3-4 weeks in order to actually become independent. Only then, the female destroys the wall and leaves the brood-cave together with the squabs. At this time, the male can hardly still meet the rising food-demand of its family. These behaviors having to do with the brood very much probably serve as protection against enemies, particularly before tree-snakes.