Sinornithosaurus form from those found on birds from the same geological deposits. The body (contour) feathers were generally between 3-4.5 cm long and included two types: the first type are formed of several filaments joined together into "tufts", similar to modern down feathers. The second type, including those on the arms, were composed of rows of filaments ("barbs") joined together along a main shaft ("rachis"), making them similar in structure to modern bird feathers. However, unlike the wing feathers of flying birds, they did not have the secondary branches with tiny little hooks ("barbules") that flight feathers have, which allow the
A Donkey, 3 Rocks, and a Bird. facing one another. The donkey has a rock balanced on its back, while the bird is both standing on a rock and balancing one on its head. The donkey has surfaces decorations, including glyphs and figures, and is coated in polychrome bronze. The bird is coated in blue, green, orange, red and yellow. The sculpture measures approximately x x . Its base is made of exposed aggregate concrete and measures approximately x x . One plaque on the base reads, . Another reads, . Inscriptions near the donkey's crotch displays the artist's last name, a copyright symbol, and the year