|The underside of an Adelie's
wing is covered by very small and compact white feathers. When the
penguin has not been walking or swimming the color appears white.
||This penguin has just
come out of the water where it was using its wings to swim. It is,
therefore, hot when it emerges onto land. More blood has gone to the
skin on the underside of its wings to help to expel this heat and
therefore the wing appears pink. Penguins don’t sweat to expel
of penguins flew both in the air and in the sea, just like auks (Northern
Hemisphere) and shearwaters (Southern Hemisphere) do today. In fact
the closest non-penguin ancestor of penguins are the shearwaters,
a family of birds that includes the most abundant of all seabirds.
Penguins lost their ability to fly in the air when, through evolution,
by changing their wings into paddles they became more successful at
catching fish.. It is far more strenuous to fly in water than in air,
however, so penguins need to have abundant food close by in order
to survive. This makes penguins more vulnerable to food shortages
than other birds. The above pictures show the difference between a
wing meant for flying in the air (skua), and one designed to fly in
the water (penguin).
|In order to form a paddle-like
wing, many of the bones that one finds in the wing of a bird that flies
in air, in penguins, have become fused together: several individual
bones becoming one bone. The bones have also become flattened.
||picture to come
|In order to flap their wings
in the water, penguins have developed HUGE breast and back muscles,
making up probably 1/4 of their entire body weight. Unlike birds that
fly in the air, which have power only on the down-stroke of the wing,
penguins power themselves both on the upstroke and the downstroke. They
can swim very fast, probably on the order of about 30-40 km per hour
at top speed.
||picture to come
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