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Some friends of mine in Arizona who have an
Emu ranch kindly sent me a nice batch of Emu feathers from various locations on
the birds. Immediately I was amazed to see that ALL the feathers are
TWINNED! It looks as though two feathers have grown out of a singular
sheath (or whatever the right word is).
Amazed, I asked them two
questions: (1) Do all Emus have twinned feathers?; and, (2) Are all
feathers on all Emus twinned?
The answer was yes, to both
questions.
So, I further asked,
(3) Are there any other birds than the Emu that have twinned
feathers?
They said that so far as they know, no
other bird has twinned feathers, and that all emu ranchers they know have
said that Emus are unique in this.
Well, of course I'm not sure of the
reliability of that last answer, because I am not convinced that Emu ranchers
are necessarily experts concerning the feathers of other birds. But, if
twinned feathers are in fact unique to Emus (or to just two or a few species of
bird), I am wondering whether feather twinning should be (or is) a
considered factor in classification, because of its uniqueness or rarity.
Also, should one consider the possibility
that feather twinning may be an adaptation to some factor in the Emu's
environment and/or lifestyle? If so, WHAT? From an evolutionary
standpoint, how did feather twinning come about, and in what ways might it be
advantageous?
Have we an expert among us that can
elucidate this quandary?
The same Arizona friends sent me some
superb photos of fresh Emu tracks. It was interesting to observe that Emu
tracks are remarkably identical -- in both shape and size -- to a certain type
of dinosaur tracks from the Early Cretaceous of Maryland.
I told this to one of the Arizona Emu
ranchers, and he responded, "No surprise. Emus ARE dinosaurs! All
the publicity in recent years declaring birds to be dinosaur descendants is
no news to me and a lot of Emu people. And dinosaurs -- at least the Emu
kind -- have a powerful weapon in their legs and feet! Heck, an Emu can
disembowel you with one strategically placed kick!"
So now I wonder whether some Mesozoic
non-avian, avian, or maybe secondarily flightless dinosaurs might have had
twinned feathers, 'proto-feathers', integumentary fibers, or
whatever.
Any clarification or help would be
appreciated.
Thanks, Ray Stanford
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