Lizards flash colors people can't see.People flirt with smiles and warn off rivals with sneers. Likewise, lizards such as this Anolis cristatellus (bottom, right) gesture, unfolding a throat fan - called a dewlap dewlap loose skin under the throat and neck which may be pendulous in some species or breeds, e.g. Bloodhounds, Indian cattle, rabbits. - to communicate. But dewlaps can send signals that humans cannot see, says Leo Leo, in astronomy Leo [Lat.,=the lion], northern constellation lying S of Ursa Major and on the ecliptic (apparent path of the sun through the heavens) between Cancer and Virgo; it is one of the constellations of the zodiac. J. Fleishman, a physiologist at Union College in Schenectady, N.Y. Images from an ultraviolet video camera (top, right) reveal a brilliant dewlap in Anolis pulchellus that contrasts sharply with the surrounding vegetation, which tends to absorb light at those wavelengths, Fleishman and his colleagues report in the Sept. 30 NATURE. In normal light, the dewlap is less flashy (top, left). Fleishman and Ellis R. Loew of Cornell University Cornell University, mainly at Ithaca, N.Y.; with land-grant, state, and private support; coeducational; chartered 1865, opened 1868. It was named for Ezra Cornell, who donated $500,000 and a tract of land. With the help of state senator Andrew D. in Ithaca, N.Y., stumbled onto special photoreceptors Photoreceptors Specialized nerve cells (rods and cones) in the retina that are responsible for vision. Mentioned in: Macular Degeneration tuned to oUV wavelengths while studying the eyes of these lizards for other reasons. They now know that many other lizards and a few snakes also possess these photoreceptors, says Loew. Among the five anole anole: see chameleon. lizards they investigated, the three that live in open, sunny areas had dewlaps that reflected UV light. The dewlaps of the other two, which live near the shaded forest floor, did not, says Fleishman. |
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