Feathers

Alpha-keratin is a type of protein found in all vertebrates to form a skin. Birds and reptiles have an additional protein called beta-keratin which is the main structure of feathers and beaks for birds, and reptilian skin and claws for reptiles. The primary feathers, known as contour feathers are the most common type of feathers found in birds. It has the long flat shape with a hollow stick called a calamus supporting the root and connecting to the rachis. Lateral barbs then branches off from the rachis creating the soft and smooth shaft of feather. The inner part of the feather serves as insulation, and the outer part is for different purposes. Barbs can be separated into three structure: barbule, barbicel, and ramus. Barbules is the thin flexible part of the feather which gives the texture. Then from that as the feather goes inward toward the body, it becomes more rigid structure to support the shape and give insulation.