[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re:Feathers again.



Date: Wed, 04 Sep 1996 10:52:59 +0200
Reply-To: fossils@redestb.es
Sender: owner-dinosaur@usc.edu
Precedence: first-class
From: "Antoni Lacasa" <fossils@redestb.es>
To: mrowe@indiana.edu, cnedin@geology.adelaide.edu.au
Subject: Re:Feathers again.
Mime-Version: 1.0

This message was submitted by "Antoni Lacasa" <fossils@redestb.es> to list
dinosaur@usc.edu. If you forward it back to the list, it will be distributed
without the paragraphs above the dashed line. You may edit the Subject: line
and the text of the message before forwarding it back; otherwise do not modify
anything else (that includes the spacing in the headers).

It is strongly advised that you do not indent the message in any shape or form
if you decide to forward it back, especially if it is MIME encoded. If your MUA
wraps your reply around into another MIME message, you may run into problems if
it modifies the headers that ListProc sent along inany shape or form; the
headers shown below that listproc sent along should not be augmented or
otherwise modified.

If you edit the messages you receive into a digest, you will need to remove
these paragraphs and the dashed line before mailing the result to the list.
Finally, if you need more information from the author of this message, you
should be able to do so by simply replying to this note.

----------------------- Message requiring your approval ----------------------
Content-Type: message/rfc822

MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 8bit
From: "Antoni Lacasa" <fossils@redestb.es>
Subject: Re:Feathers again.

LN Jeff wrote:

 Does anyone have data on how much better birds with waterproofed
feathers retain heat when they get wet than mammals?

I think that this structures are good in every case (mammals and birds).
Feathers and hair keep well the temperature in birds and mammals
respectively.In birds keep 39º-41,7º c. average body temperature and in
mammals about of 37º-38,5ºaverage. But the waterproofing is a little
different.In mammals intermittently linked to aquatic environments
(e.g.otters and others)requires waterproofing which makes it possible to
keep the downy  insulating layer dry, as well as trapped air remaining in
contact with te body.This is achieved by production and spreading grease
overs surface of the fur from sebaceous glands in the pilous follicles,
structures absent from the avian integument. In birds, the waterproofing
is on the closed network between its barbs and barbules in pinnate area
of body feathers and in its keratinous structure and perhaps a little the
oil of uropigial gland.
My opinion about it is that an ancestral group of dino-birds acquired
incipient feathers as an answer to their adaptation to continental
aquatics mediums in predatory incursions in the water in search food,
would tend to reduce body temperature A insulate and waterpoofing feather
covering,  would preserve the head body.

Toni fossils.