Equile, dark hair – similar to that of a contemporary mole or bat. For example, the fur of early mammals looked out about 160 million years ago, concludes an international team of paleontologists this week in Sciencebased on six fossils from the Mesozoic and the hairs of 116 still living mammal species. That monotonous appearance was logical, because the primordial species were probably nocturnal animals.
Colors can have all kinds of functions in nature: from warning and tempting to regulating body temperature. With mammalian coats, the palette is generally limited, with many brown and gray tones, but patterns often cause variation: think of the dots of the Damhert, the stripes of the tiger, the spots of the leopard.
Little was known about the evolution of those colors and patterns. For a long time it was even considered impossible to determine the color of fossil species. About twenty years ago that changed, when paleontologists discovered that melanosomes are sometimes still present in fossils. Those cell components with melanine figure provide the color for vertebrates.
Black, brown, yellow, red
Mammal melanosomes contain two variants of melanin: eumelanin (responsible for black and brown) and feomelanine (for yellow and red). Those pigments absorb certain wavelengths of the light and ensure certain colors. In principle, the shape of the melanosomes can be seen which color can ultimately be seen.
By comparing fossil melanosomes with those of living species, you can therefore find out the color of extinct animals, the paleontologists reasoned in the current study.
They first studied the relationship between melanosomes form and color in the hair of 116 living mammals. With red and yellow coats, for example, the melanosomes turned out to be rounder than with brown and black. A large melanosomy density meant a red color, a low precisely a yellow one. And, striking: under the microscope, almost every mammal hair hair was brown – even if it was part of a ‘gray’ or ‘black’ fur.
They then compared the fossil melanosomes of six extinct primal mammals with contemporary hairs. The fur of the primal animals turned out to be dark in color (with brown hair) and moreover evenly – without pattern formation. Earlier, other research (into the evolution of eye shape and color perception in mammals) had shown that the early species probably all lived at night. The publication in Science After all, underlines that conclusion now: nocturnal animals have nothing to do with bright colors or patterns to communicate with each other.