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Re: Status of _Caudipteryx_



In a message dated 12/30/00 11:03:54 AM, jrccea@bellsouth.net writes:

<< >From this, I gather that your definition of 'flying' means that the 
animal must
be able to maintain altitude.  Any gliding animal can maintain altitude when
local convective or orographic lift or energy available from local wind shear
exceeds their sink rate.  Does this mean that they become flyers whenever by
happenstance, atmospheric lift is greater than their sink rate?  If so, then
flying lemurs are indeed flyers.  If not, then animals which gain altitude in
local lift and convert the additional potential energy to glide to the next
source of local lift are not flyers.  Thus, nonflyers would include buzzards,
frigate birds, albatrosses, and some pterosaurs, among others.  Is this your
intent, or am I misreading you? >>

Well, flying squirrels jump off limbs of trees and use their flaps to 
maintain altitude and retard the rate of fall. Same with colugos. That's 
gliding.

Buzzards, frigate birds, and albatrosses can get airborne on their own power, 
and maintain airborne status, which is something colugos and squirrels can't. 
Interestingly, freshwater hatchetfish [available at your friendly local 
aquarium shop], vibrate their fins in order to maintain "powered flight." I 
learned this when I was a kid and forgot to put the screen top back on the 
tank. The damn thing jumped out and flew seventy feet to the other side of 
the rec room.

Flying fish, use their tails to get airborne and can't maintain flight at 
all. Therefore they glide, not fly.

eric l.