Feather

Feathers are one of the epidermal growths that shape the distinctive outer covering, or plumage, on birds. They are the outstanding feature that distinguishes the Class Aves from all other living groups. Other Theropoda also had feathers to see feathered dinosaurs.

Characteristics

Feathers are among the most multifaceted structural organs found in vertebrates: integument appendages, formed by controlled explosion of cells in the epidermis, or outer skin layer that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are calm of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and cross linked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof.
Feathers are one of the epidermal growths that shape the distinctive outer covering, or plumage, on birds. They are the outstanding feature that distinguishes the Class Aves from all other living groups. Other Theropoda also had feathers to see feathered dinosaurs.