Tucano

São designadas por tucano as aves da família Ramphastidae que vivem nas florestas da América Central e América do Sul.

Possuem um bico grande e oco. A parte superior é constituída por trabéculas de sustentação e a parte inferior é de natureza óssea. Não é um bico forte, já que é muito comprido e a alavanca (maxilar) não é suficiente para conferir tal qualidade. Seu sistema digestivo é extremamente curto, o que explica sua base alimentar, já que as frutas são facilmente digeridas e absorvidas pelo trato gastrointestinal. Além de serem frugívoros (comerem fruta), necessitam de um certo nível protéico na dieta, o qual alcançam caçando alguns insetos, pequenas presas (como largarto, perereca, etc) e mesmo ovos de outras aves. Possuem pés zigodáctilos (dois dedos direcionados para frente e dois para trás), típicos de animais que trepam em árvores.

São monogâmicos territorialistas (vivem e se reproduzem em casal isolado). Não há dimorfismo sexual e a sexagem é feita através de DNA. A fêmea e o macho trabalham no ninho, que é construído em ocos de árvores. A fêmea choca e o macho a alimenta. Fazem postura de 3 a 4 ovos, cujo período de incubação é de 18 dias.

O tucano ainda não é uma espécie ameaçada de extinção, entretanto tem sido capturado e traficado para outros países a fim de ser vendido em lojas de animais. Isto tem como conseqüência a diminuição de sua população nas florestas, pondo em risco a variabilidade genética, como também a morte de muitos animais durante o transporte.

Não são aves migratórias.

Lista de espécies
Aulacorhynchus
Aulacorhynchus sulcatus
Tucaninho verde, Aulacorhynchus derbianus
Aulacorhynchus haematopygus
Aulacorhynchus huallagae
Aulacorhynchus coeruleicinctis
Pteroglossus
Araçari-miúdo-de-bico-riscado, Pteroglossus inscriptus
Araçari-miudinho, Pteroglossus viridis
Araçari-de-pescoço-vermelho, Pteroglossus bitorquatus
Araçari-de-bico-de-marfim, Pteroglossus azara
Araçari-de-bico-marrom, Pteroglossus mariae
Araçari-castanho, Pteroglossus castanotis
Araçari-de-bico-branco, Pteroglossus aracari
Pteroglossus torquatus
Araçari de Frantzius, Pteroglossus frantzii
Pteroglossus sanguineus
Pteroglossus erythropygius
Araçari-cinta-dupla, Pteroglossus pluricinctus
Araçari-mulato, Pteroglossus beauharnaesii
Baillonius
Araçari-banana, Baillonius bailloni
Andigena
Andigena laminirostris
Andigena hypoglauca
Andigena cucullata
Andigena nigrirostris

Xilogravura de um tucano.Selenidera
Selenidera spectabilis
Saripoca-de-coleira, Selenidera reinwardtii
Saripoca-de-bico-castanho, Selenidera nattereri
Araçari-negro, Selenidera culik
Araçari-poca, Selenidera maculirostris
Saripoca-de-Gould, Selenidera gouldii
Ramphastos
Ramphastos sulfuratus
Ramphastos brevis
Ramphastos citreolaemus
Ramphastos culminatus
Tucano-de-bico-preto, Ramphastos vitellinus. O Ramphastus vitellinus pintoi é considerado extinto no estado de São Paulo.
Tucano-de-bico-verde, Ramphastos dicolorus
Ramphastos swainsonii
Ramphastos ambiguus
Tucano-grande-de-papo-branco, Ramphastos tucanus
Ramphastos cuvieri
Tucano-toco, Ramphastos toco, freqüentemente chamado apenas de Tucano

Toucan

Toucans are a family, Ramphastidae, of near-passerine birds from the neotropics (i.e. the Central, South American, and Caribbean region). The family is most closely related to the American barbets. They are brightly marked and have large, colorful bills. The family includes five genera and about forty different species. The name of this bird group is derived from Tupi tucana, via French.

Contents [hide]
1 Morphology
2 Behavior
3 Systematic list
4 In Aztec Mythology
5 References
6 External links



[edit] Morphology
Toucans range in size from the Lettered Aracari (Pteroglossus inscriptus), at 130 g (4.6 oz) and 29 cm (11.5 inches), to the Toco Toucan (Ramphastos toco), at 680 g (1.5 lb) and 63 cm (29 inches). Their bodies are short (of comparable size to a crow's) and compact. The tail is rounded and varies in length, from half the length to the whole length of the body. The neck is short and thick. The wings are small, as they are forest-dwelling birds who only need to travel short distances, and are often of about the same span as the bill-tip-to-tail-tip measurements of the bird.

The legs of a toucan are strong and rather short. Their toes are arranged in pairs with the first and fourth toes turned backward. The majority of toucans do not show any sexual dimorphism in their coloration, the genus Selenidera being the most notable exception to this rule (hence their common name, "dichromatic toucanets"). However, the bills of female toucans are usually shorter, deeper and sometimes straighter, giving more of a "blocky" impression compared to male bills. The feathers in the genus containing the largest toucans are generally black, with touches of white, yellow, and scarlet. The underparts of the araçaris (smaller toucans) are yellow, crossed by one or more black or red bands. The toucanets have mostly green plumage with blue markings.


Keel-billed Toucan (Ramphastos sulfuratus)The colorful, giant bill, which in some large species measure more than half the length of the body, is the hallmark of toucans. Despite its size it is very light, being composed of bone struts with little solid material between them. The bill has forward-facing serrations resembling teeth, which historically led naturalists to believe that toucans captured fish and were primarily carnivorous, but today we know that they eat mostly fruit. Why the bill is so large and brightly colored is still debated and may be complex. As there is no sexual dimorphism in coloration it is unlikely to be a sexual signal; It does aid in their feeding behavior (as they sit in one spot and reach for all fruit in range, thereby reducing energy expenditure). It has also been theorised that the bill may intimidate smaller birds, so that the toucan may plunder nests undisturbed (see Behaviour). Also, the beak allows the bird to reach deep into treeholes to access food unavailable to other birds, and also to depredate suspended nests built by smaller birds.

A toucan's tongue is long (up to 14-15 cm, or 6 inches), narrow, grey, and singularly frayed on each side, adding to its sensitivity as an organ of taste.

A structural complex probably unique to toucans involves the modification of several tail vertebrae. The rear three vertebrae are fused and attached to the spine by a ball-and-socket joint. Because of this, toucans may snap their tail forwards until it touches the head.[1] This is the posture in which they sleep, often appearing simply as a ball of feathers, with the tip of the tail sticking out over the head.


[edit] Behavior

Toucans, like this Red-breasted Toucan (Ramphastos dicolorus), nest in hollows in treesToucans are primarily frugivorous (fruit eating), but are opportunistically omnivorous and will take prey such as insects and small lizards.[2] Captive toucans have been reported to actively hunt insects in their cages, and it is possible to keep toucans on an insect-only diet. They also plunder nests of smaller birds, taking eggs and nestlings.[3] This probably provides a crucial addition of protein to their diet. However, in their range, toucans are the dominant frugivores, and as such play an extremely important ecological role as vectors for seed dispersal of fruiting trees.[4]

Toucans are arboreal and typically lay 2–4 white eggs in their nests. They make their nests in already-existing treeholes like natural cavities and holes excavated by other animals such as woodpeckers - the toucan bill has very limited use as an excavation tool. When the eggs hatch, the young emerge completely naked, without any down. Toucans are resident breeders and do not migrate. Toucans are usually found in pairs or small flocks. They sometimes fence with their bills and wrestle, which scientists hypothesize they do to establish dominance hierarchies.


[edit] Systematic list
Genus Aulacorhynchus - green toucanets (6-13 species, depending on taxonomy)
Genus Selenidera - dichromatic toucanets (6 species)
Genus Andigena - mountain toucans (4 species)
Genus Pteroglossus - araçaris (14 species, incl. Saffron Toucanet)
Genus Ramphastos - typical toucans (about 8 species)

[edit] In Aztec Mythology
The ancient Aztecs believed that the toucan's beak was created from rainbows. It was said to be the toucans' reward for being messengers of the gods. The Aztecs would perform ancient rituals worshiping the toucans, believing that because their beak was created from rainbows, that the gods would grant them rain. The ritual involved a member of the chosen family to wear a headress of toucan feathers, and plead the toucan for rain. If rain did not come within three days, (according to the Aztec Calendar,) it would be offered back to the gods on a pyre with a ceremonial burning.[citation needed]