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Ever wonder how dogs can walk barefoot in the snow? Now a Japanese scientist may have the answer -- an internal central heating system, Reuters reported.

The secret lies in how dogs circulate their blood to prevent cold surfaces from chilling the rest of their bodies, according to Hiroyoshi Ninomiya, a professor at Yamazaki Gakuen University.

The system uses warm, oxygenated blood to heat the cold blood that has been in contact with a cold surface before returning it to the dog's heart and central circulation.

Dogs are not alone in having this sort of heat exchange system, which is shared by other animals such as dolphins, Ninomiya said. （点击路透社网站查看原文）

为什么狗狗不怕冷？

       可曾想过狗狗为何能光脚在雪地上行走自如？路透社报道称，日本科学家可能已找到答案——因为它们的脚掌上有个內部中央加热系統。

       东京山崎学园大学教授二宮博义研究指出，奧秘之处在于，狗狗是如何使血液循环起来，以避免冰冷的地面导致身体受寒。

       其实，这套机制是利用温暖的含氧血液来为接触冰冷地面的冷血液加温，然后再将其送回心脏和中央循环系統。

       二宮表示，狗狗并不是唯一拥有这种热交换系统的动物，海豚等其它动物也具有该机制。

(China.org.cn March 8, 2012)