Down feathers of geese insulate through special architecture.
Image: Alan Wilson /

Canada Goose, Colony Farm Regional Park, Port Coquitlam, British Columbia. 2005

Image: Fuzzy Thompson /

“Feather keratin occurs in a ‘b-sheet’ configuration which differs from the a-helices that occur in mammalian keratins. . . We have measured the properties of individual down feathers from ducks, geese and penguins and found that their properties are similar to flight feathers and, indeed, the man-made s used in artificial insulation fibres. The message is that the architecture of down feathers is probably more important than material properties in determining their advantages over synthetic materials. . .Recently, we have begun to explore the toughness of feather keratin by using instrumented clippers and scissors. The fracture toughness of β-keratin has proved to be very high, around 10 kJ m-2.” (Bonser 2007)

Illustration comparing the structure of keratin in goose down to the hair of a small mammal. The helical structure of the keratin in the down appears to be looser while the mammal hair has a tighter coil. mammal.
Image: Emily Harrington / Copyright © - All rights reserved

Comparison of keratin structure in down feathers and mammal hair.

Last Updated August 18, 2016