This two-foot-long lizard lives in the more arid parts of Australia.
"They can change color really quickly, just in a matter of seconds or minutes."
University of Melbourne biologist Katie Smith.
"And they do this by moving pigments within specialized skin cells called chromatophores."
Bearded dragons modify their colors for camouflage, or to maintain their body temperature, or to communicate with other dragons. Smith wanted to know how they meet all those needs with the same tool kit.
So she and her team rounded up twelve bearded dragons and put them through a series of tests before releasing them back into the wild. They found that when the dragons want to communicate with other members of their species, they change the colors on their neck.
"This is actually one of the reasons they're called bearded dragons—because they look like they have a really serious five o'clock shadow."
Changes to their backs were for temperature regulation. Shifting to yellow lets them to cool off during extreme heat, while darker greys allow them to soak up more heat during cooler weather.
"They actually save about, on average, 22 minutes a day at the darker colors than the lighter colors. That's about 85 hours throughout the whole year."
Eighty-five hours a year NOT spent out in the open and exposed to potential predators. The results were published in the Proceedings of the Royal Society: B.
The lizards can clearly control each part of their body separately, resulting in an efficient system. Temperature regulation involves the back, which is facing the sun. Social signaling uses the neck, easily visible to another lizard they're faced off with.
The researchers' next task is to see what happens when the lizards have to deal with simultaneous but conflicting coloration requirements—situations that could give a bearded dragon a close shave.
很多動物會進化顏色讓自己隱藏起來 。美洲豹身上的斑紋讓它可以在陽光斑駁的雨林地帶潛行 。一些動物翅膀上的斑駁沉著色素可以讓它們在樹上休息時不被打擾 。另外，還有些動物可以快速改變它們的外表，比如鬃獅蜥 。
這種兩英尺長的蜥蜴生活在澳大利亞的干旱地區 。
“它們可以非常快速地改變顏色，僅僅只需要幾秒鐘或者幾分鐘的時間 。”
凱蒂·史密斯是墨爾本大學的生物學家 。
“它們通過轉移特定皮膚內細胞內的色素來實現的 。”
鬃獅蜥通過改變自己的顏色進行偽裝、保持體溫，或和其他鬃獅蜥進行交流 。史密斯想知道擁有同樣保護偽裝的鬃獅蜥是如何滿足這些需求的 。
所以，她和自己的團隊找了十二只鬃獅蜥，對它們進行了一系列的測試，然后再把它們放回野外 。他們發現，當鬃獅蜥想和本物種的其他成員進行交流時，它們會改變自己頸部的顏色 。

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