據(jù)7月24日的《科學》雜志報道說，一項新的研究提示,，如同大象的耳朵一樣,，巨嘴鳥的喙可像一個相當有效的散熱器一樣運作，即在該鳥需要降低體溫的時候將身體的熱量排放出去,。
托哥巨嘴鳥（toco toucan ）的喙在動物奇觀堂中占有一席特殊的位置,。 該鳥的喙占了其整個身長的約1/3，相對于其身體大小來說,，它的喙是所有鳥中最大的,。 研究人員在幾個世紀以來一直對該鳥喙的功能感到困惑，有人提出,，其功用可能與吸引配偶或處理果實有關,。 Glenn Tattersall及其同僚對一種替代性的解釋進行了調(diào)查。他們用紅外熱成像（即熱感應攝相機）來監(jiān)視接觸不同環(huán)境溫度時的巨嘴鳥,。 研究人員觀察到,，該鳥喙的表面溫度在其環(huán)境變熱或變冷時會快速地改變。 例如,，在日落的時候,，當巨嘴鳥即將入眠的時候，其鳥喙會在幾分鐘內(nèi)降溫約10攝氏度,。 這種鳥因此看來是在用它們的喙（該鳥喙上有許多血管,，可使其體熱被攜往該鳥喙的表面附近）來散發(fā)體熱，這樣,，它們可以在睡眠的時候降低其體溫,。 文章的作者猜測，其它的鳥類（由于無法出汗）可能也是用它們的喙來達到這一目的的,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 24 July 2009: DOI: 10.1126/science.1175553
Heat Exchange from the Toucan Bill Reveals a Controllable Vascular Thermal Radiator
Glenn J. Tattersall,1,3 Denis V. Andrade,2,3 Augusto S. Abe2,3
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. Here we show the remarkable capacity of the toco toucan to regulate heat distribution by modifying blood flow, using the bill as a transient thermal radiator. Our 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.
1 Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada.
2 Departamento de Zoologia, Universidade Estadual Paulista, Campus Rio Claro, S?o Paulo, Brazil.
3 Instituto Nacional de Ciência e Tecnologia em Fisiologia Comparada.
