3. Feathers
Feathers are the most
distinctive feature of
avian anatomy
Specialized filament
structures of the skin
attach to bird’s skeleton
Collectively referred as
plumage
4. Primary role:
o Insulation
o Aerodynamic (Role in flight)
o Coloration
Secondary role:
o Swimming
o Sound production
o Cleanliness
o Camouflage
o Courtship
5. Feathers Structure
Feathers consist of a fibrous protein polymer
mainly beta-keratin
Beta-keratins have some mechanical properties
similar to those of the alpha- keratins found in the
skin of all vertebrates
Beta-keratins are unique to reptiles and birds,
make up most of the hard structures of reptilian
skin and the leg scutes, claws, and beaks of birds
Feather keratins are a special class of beta-keratins
that are characterized by a small deletion in their
molecular sequence
6. There are different kinds of feathers but not all
types of feathers provide role in aerodynamics
Flight feathers Contour feathers
Contour feathers
Type of feather help in flight
8. Primary features of contour feather
The primary features of a typical contour feather
are a long central shaft and a broad flat vane on
either side of this shaft
Vane
The flat part on either side of the shaft of a
feather
Calamus
The hollow inner portion of the feather shaft that
lacks barbs and attaches to the skin
Held in the feather follicle on the skin of the bird
9. Rachis
The rest of the shaft after the calamus called as
rachis
Filaments of barbs attached with rachis
Barb
An individual strand of feather material
extending laterally from the rachis
Ramus
Each barb consists of a tapered central axis called
as the ramus, with rows of smaller barbules
projecting from both sides
10. Barbule
The barbs possess further branches — the
barbules
The cells may be simple or may bear
projections called barbicels
Barbicel / Hooklets
The small hook-bearing processes on a
barbule of a feather
Hook like structures present on barbules
11.
12.
13. Plumulaceous vane
Each vane of a typical body feather grades
from a hidden and fluffy basal part, provides
insulation to an exposed outer part
The barbules on the barbs at the base of the
body feather are long, thin, and flexible and
do not have barbicels
With their similarly thin, flexible parent barbs,
they create a downy or plumulaceous feather
texture
14. Pennaceous vane
The outer part of the vane is a firmly textured
and tightly interlocking which forms
pennaceous structure
The outer vane is based on the interlocking
arrangement of pennaceous barbules
Well-developed hooklet barbicels are present
on the pennaceous barbules
15. Afterfeather
The body feathers of some birds
include a secondary structure
called as afterfeather or
aftershaft
It is a mirror-image shaft and
vane, attached to the same
calamus
The barb and barbule structure of
afterfeathers is typically
plumulaceous, with rare
exceptions
The afterfeather's primary
function is to enhance insulation