Ramphastidae – Aracari, Toucans & Toucanets

The Ramphastidae or Toucans are members of a family of near passerine birds from the Neotropics. They form part of the order Piciformes, along with Lybiidae (African Barbets), Megalaimidae (Asian Barbets), Capitonidae (New World Barbets), Semnornithidae (Toucan-barbets), Indicatoridae (Honeyguides) and Picidae (Woodpeckers). They are most closely related to the American barbets. They are brightly marked and have large, often colourful bills. The family includes five genera and over forty different species.

Toucans range in size from the Lettered Aracari at 130g and 29cm to the Toco Toucan at 680g and 63cm. 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.

Black-necked Aracaris Pteroglossus aracari

Their legs 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.

Guianan Toucanet Selenidera piperivora	Saffron Toucanet Pteroglossus bailloni
Emerald Toucanet Aulacorhynchus prasinus wagleri	Spot-billed Toucanet Selenidera maculirostris

The colourful and large bill, which in some large species measures more than half the length of the body, is the hallmark of toucans. Despite its size, the toucan’s bill is very light, being composed of bone struts filled with spongy tissue of keratin between them. The bill has forward-facing serrations resembling teeth, which historically led naturalists to believe that toucans captured fish and were primarily carnivorous; today it is known that they eat mostly fruit. Researchers have discovered that the large bill of the toucan is a highly efficient thermoregulation system, though its size may still be advantageous in other ways. It does aid in their feeding behaviour (as they sit in one spot and reach for all fruit in range, thereby reducing energy expenditure), and it has also been theorised that the bill may intimidate smaller birds, so that the toucan may plunder nests undisturbed. Also, the beak allows the bird to reach deep into tree-holes to access food unavailable to other birds, and also to ransack suspended nests built by smaller birds. However, as there is no sexual dimorphism in coloration it is unlikely to be a sexual signal.

Crimson-rumped Toucanet Aulacorhynchus haematopygus

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

Plate-billed Mountain Toucan Andigena laminirostris

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 forward until it touches the head. 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.

Green-billed Toucan Ramphastos dicolorus

Green Aracari Pteroglossus viridis

Toucans are primarily frugivorous (fruit eating), but are opportunistically omnivorous and will take prey such as insects and small lizards. Captive toucans have been reported to hunt insects actively 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.

Many-banded Aracari Pteroglossus pluricinctus

This probably provides a crucial addition of protein to their diet. Certainly, apart from being systematically predatory as well as frugivorous, like many omnivorous birds, they particularly prefer animal food for feeding their chicks. 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.