The growth of keratin cells, or keratinocytes, in the epidermis of the follicle—the follicle “collar”—forces older cells up and out, eventually creating the entire feather in an elaborate choreography that is one of the wonders of nature.
The growth of keratin cells, or keratinocytes, in the epidermis of the follicle—the follicle “collar”—forces older cells up and out, eventually creating the entire feather in an elaborate choreography that is one of the wonders of nature.
角质细胞在毛囊的表皮部位（像毛囊的领子）生长，迫使较老的细胞往上、往外推，终而制造出一整支羽毛；整个过程有如复杂精细的舞步，堪称自然界的奇景。