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Thermodynamic Mysteries: How Does A Toucan Keep its Cool?

written by: Dr. Crystal Cooper•edited by: Lamar Stonecypher•updated: 5/26/2010

Toucans are large birds that largely reside in South and Central American, though there are some in Mexico. They are famous for the size and colorfulness of their beaks. But exactly why did nature see fit to grace this noisy, colorful bird with such an enormous bill?

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    Introduction

    Nature is filled with mammals with unusually large nasal appendages. Elephants are amongst the most well-known, and there are several animals such as duck-billed platypuses, anteaters, alligators, and even giraffes. Human beings are not exempt, though the nose size is relative. The late Jimmy Durante made a living capitalizing on his proboscis, calling himself "The Great Schnozzola" or "Schnozzle."

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    Toucans

    Ramphastos toco Toucans are tropical birds that reside primarily in South and Central America, though some have been found as far North as Mexico. Their noses can grow as long as approximately one third the size of their body, with toco toucans having the largest ones of all. Ramphastes toco grows up to 24 inches (62 cm) in height, and has the largest bill. The smallest size toucans, in contrast, are 12 - 14 inches (30 - 36 cm). For hundreds of years, researchers have wondered why such a large beak is on such a bird and have advanced different theories on its usage.

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    Food?

    Researchers are well aware of the reasons why nature has endowed creatures with an olfactory blessing. It helps them find and obtain food. In the case of toucans however, some believe that this reason does not hold water. Their diet consists of small fare such as fruit, berries, and seeds. They are also known to eat insects, snakes, frogs, small mammals, eggs, and baby bird nestlings. They eat their food with a deftness and precision, grabbing their feasts with their bills and tossing their heads back to swallow. This seems to therefore make having such a large nose overkill.

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    Fear?

    Toucans don't have many predators. Humans, of courses, will capture or hunt them, and jaguars and hawks view them as tasty meals. Researchers have speculated that the bills are to scare away hawks. The bill is light in weight and has many air pockets. It is basically hollow and is made of keratin. Because it offers no protection, inspiring fear in enemies does not seem to be a factor in its construction.

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    Amour?

    Researchers have considered that toucans have large noses in order to attract the opposite sex. After all, nature's denizens commonly have exaggerated features that help in the eternal pursuit of love. Male peacocks strut their large colorful tail feathers before admiring females. The monogamous male Northern Cardinal sports a brilliant scarlet plumage that helps him find his true love. However, some researchers also dislike this theory. Both male and female toucans have large beaks, though the male's does tend to be slightly larger.

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    Heat Sink?

    Finally, a group of biology and zoology university researchers conceived of a novel approach. Animals that live in hot regions, such as elephants, desert foxes, and jackrabbits, use their ears as thermal radiators in order to regulate their body temperature. When cold, they decrease the flow of blood to their ears, and when hot, they increase the amount, so that the ears radiate heat. Their ears function as heat sinks and cool their blood. Might not this same theory of temperature regulation therefore apply to toucans? If so, how could this be proved?

    The justifications for their reasoning and the experiments they used to advance their theory will be examined in part two.

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    Image Credits

    Ramphastos toco by Mateus Hidalgo

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    References

    McGowan, Kevin J. McGowan, Kevin J. Toucan. World Book Advanced. World Book, 22 Dec. 2009

    Toucans.Net: The Toucan Bird

    Toucan. Encyclopædia Britannica Online. Encyclopædia Britannica, 24 Oct. 2009

    Callaghan, Amy. Toucan's Beak is Massive Radiator. Cosmos Online, 24 July 2009