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Content with tag pigmentation .

Unprecedented high catecholamine production causing hair pigmentation after urinary excretion in red deer

Hormones have not been found in concentrations of orders of magnitude higher than nanograms per milliliter. This study reports urine concentrations of a catecholamine (norepinephrine) ranging from 0.05 to 0.5 g/l, and concentrations of its metabolite dl-3,4-dihydroxyphenyl glycol (DOPEG) ranging from 1.0 to 44.5 g/l, in wild male red deer Cervus elaphus hispanicus after LC–MS analyses. The dark ventral patch of male red deer, a recently described sexually selected signal, contains high...

Recent shift in the pigmentation phenotype of a wild Neotropical primate

The colors of primates are among the most diverse phenotypes in mammals. These colors are mostly produced by the deposition of melanin pigments in hairs. Many species show considerable variability in pigmentation, but this is always temporarily fixed. Here the first rapid change in the pigmentation phenotype of a primate is reported. In the last five years, the pelage of mantled howler monkeys Alouatta palliata inhabiting Costa Rica has started to change from fully black to yellowish,...

Solar and terrestrial radiations explain continental-scale variation in bird pigmentation

Animals living on the earth's surface are protected from the damaging effects of solar ultraviolet (UV) radiation by melanin pigments that color their integument. UV levels that reach the earth's surface vary spatially, but the role of UV exposure in shaping clinal variations in animal pigmentation has never been tested.

Molecular vibration as a novel explanatory mechanism for the expression of animal colouration

Animal colouration is characterized by the concentration of pigments in integumentary structures and by the nanoscale arrangement of constitutive elements. However, the influence of molecular vibration on colour expression has been overlooked in biology. Molecular vibration occurs in the infrared spectral region, but vibrational and electronic properties can influence each other. Thus, the vibration of pigment molecules may also affect their absorption properties and the resulting colours....

Dark pigmentation limits thermal niche position in birds

Animal pigmentation has evolved because of several adaptive functions. In the case of pigmentation produced by melanins, the most common pigments in animals, the main function is protection against UV radiation. However, pigmentation also affects animal surface's ability to absorb solar radiation and gain heat, which may represent a thermal constraint for endotherms. Here, a detailed quantification of the expression of pigmentation phenotypes produced by melanins in 96 species of birds...
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