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Bill used as heat exchanger for thermoregulation: toco toucan

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Toco toucan / Giles Pretet / LicenseCC-by-sa - Attribution Share Alike

Bill of toco toucan acts as a heat exchanger to regulate body temperature by adjusting blood flow

"The toco toucan (Ramphastos toco), the largest member of the toucan family, possesses the largest beak relative to body size of all birds. This exaggerated feature has received various interpretations, from serving as a sexual ornament to being a refined adaptation for feeding. However, it is also a significant surface area for heat exchange. The toco toucan has the remarkable capacity to regulate heat distribution by modifying blood flow, using the bill as a transient thermal radiator. Results indicate that the toucan's bill is, relative to its size, one of the largest thermal windows in the animal kingdom, rivaling elephants’ ears in its ability to radiate body heat." (Tattersall et al. 2009:468)

Watch Video
Sleep-state transitions witnessed as changes in bill temperature. This is a thermal imaging video showing transient changes in bill temperature that occur during sleep while the bill is tucked between the wings. Time-lapsed data obtained at 10-s intervals. Total frames = 724, total length = 2.7 hours. Filmed by the Tattersall Laboratory.

Heat exchange in toucan bill. Artist: Emily Harrington. Copyright: All rights reserved. See gallery for details.

About the inspiring organism
Med_tocotoucan Toco Toucan
Ramphastos toco Statius Muller, 1776

Habitat(s): Forest, Grassland
Natural History Information:

Animal Diversity Web external link
Lorri R. Marek
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Ramphastos toco occupies the canopy layer of the tropical rainforest. It avoids dense rainforests,preferring more open habitats, such as woodlands, river forests, plantations, and palm grooves. It is commonly observed near human dwellings and it is abundant throughout its range.

Physical Description

Ramphastos toco is the largest member of its family, which comprises 37 species. It is 25 inches long. The appearance of R. toco is very colorful. Males and females are alike in color and there is no sexual dimorphism (Hanzak and Formanek, 1977). The most outstanding feature of this species of bird is its bill, which is enormous and brightly colored. The bill may be up to 71/2 inches long and is constructed of a honeycomb of bony material. The huge golden-yellow bill looks heavy, but it actually weighs little because it contains many air pockets. The tongue of R. toco is long, narrow, and singularly frayed on each side. This narrow tongue resembles a feather. Each eye is surrounded by an area of bare skin that is usually a brightly-colored orange. The plumage is black except for the white throat. The legs are strong and rather short with large scales. The claws are used for grasping branches. To enable it to grasp the branch, the toucan has two toes point forward and two backward. The tail tends to be long and nearly square. No geographic variation has been reported (Whitfield, 1998).


Ramphastos toco is a very noisy member of the jungle society. The bird lives in small communities equivalent to several families. It actively travels in small noisy flocks of half a dozen birds. For only short distances, Ramphastos toco flies gracefully. The bird beats its wings several times and glides. It is more agile in the trees, where it can hop from one branch to another. As with other brightly-colored forest birds, R. toco can hardly be seen, especially when it sits quietly, because its broken patterns harmonize with its surroundings. Its vibrant splashes of color are regarded as a flower or fruit to the eye that notices it. Although the bird's coloring has significant concealing value, R. toco often makes its presence known by its noisy chatter. It has a loud monotonous call that can be heard a half mile away in the jungle (Austin, 1983). This bird is a very playful animal and enjoys a variety of games. One of the favorites is a form of beak wrestling. During the nuptial display, both partners play a game which consists of tossing fruit to each other. After their ritual berry tossing, the birds mate and the female lays her eggs in a nest. Both parents actively take part in caring for the offspring (Skutch, 1996). Although the specific functions of the bill are poorly understood, it may play an important part in the courtship display. As a defensive weapon, the bill serves more as a frightening instrument than as a fighting tool. The bill provides little protection against predators. To escape predation, R. toco hides in a hollow tree. Another interesting behavior of R. toco is the way in which it sleeps. When the bird sleeps, it turns its head so that its long bill rests on its back and the tail is folded over its head. The bird becomes a ball of feathers. Five or six adults may sleep in a single hole, folding their tails over their backs to save space in crowded quarters (Austin, 1983).

Learn more at
Some organism data provided by: ITIS: The Integrated Taxonomic Information System
Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Threat Categories LONG_LC IUCN Red List Status: Least Concern

Bioinspired products and application ideas

Application Ideas: Energy efficient building HVAC systems, such as solar hot water systems and heat/energy recovery ventilators.

Industrial Sector(s) interested in this strategy: green building, energy systems

Tattersall Laboratory: Thermoregulatory and Metabolic Physiology of Animals
Glenn Tattersall
Department of Biological Sciences, Brock University
Tattersall, GJ; Andrade, DV; Abe, AS. 2009. Heat exchange from the toucan bill reveals a controllable vascular thermal radiator. Science. 325(5939): 468-470.
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over 6 years ago
See a video interview with Dr. Tattersall at this site (scroll down to article titled "Heat exchange from the toucan bill":
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