据7月24日的《科学》杂志报道说，一项新的研究提示，如同大象的耳朵一样，巨嘴鸟的喙可像一个相当有效的散热器一样运作，即在该鸟需要降低体温的时候将身体的热量排放出去。
托哥巨嘴鸟（toco toucan ）的喙在动物奇观堂中占有一席特殊的位置。 该鸟的喙占了其整个身长的约1/3，相对于其身体大小来说，它的喙是所有鸟中最大的。 研究人员在几个世纪以来一直对该鸟喙的功能感到困惑，有人提出，其功用可能与吸引配偶或处理果实有关。 Glenn Tattersall及其同僚对一种替代性的解释进行了调查。他们用红外热成像（即热感应摄相机）来监视接触不同环境温度时的巨嘴鸟。 研究人员观察到，该鸟喙的表面温度在其环境变热或变冷时会快速地改变。 例如，在日落的时候，当巨嘴鸟即将入眠的时候，其鸟喙会在几分钟内降温约10摄氏度。 这种鸟因此看来是在用它们的喙（该鸟喙上有许多血管，可使其体热被携往该鸟喙的表面附近）来散发体热，这样，它们可以在睡眠的时候降低其体温。 文章的作者猜测，其它的鸟类（由于无法出汗）可能也是用它们的喙来达到这一目的的。（生物谷Bioon.com）
生物谷推荐原始出处：
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.
