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From: friesen@psivax.UUCP (Stanley Friesen)
Newsgroups: net.bio
Subject: Re: Flying dinosaurs.
Message-ID: <778@psivax.UUCP>
Date: Mon, 7-Oct-85 12:25:59 EDT
Article-I.D.: psivax.778
Posted: Mon Oct  7 12:25:59 1985
Date-Received: Sat, 12-Oct-85 14:34:19 EDT
References: <148@winston.UUCP>
Reply-To: friesen@psivax.UUCP (Stanley Friesen)
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 53
Summary: 

In article <148@winston.UUCP> kovish@winston.UUCP (Barrie Kovish) writes:
>[]
>
>Maybe these large flying reptiles were filter feeding plankton eaters!
>I am using the word plankton to indicate small airborn organisms
>probably insects...
>There are several reasons to believe this proposal is possible.
>
>1. There are known examples of avian plankton eaters today. The frogmouths 
>   (birds) which attract insects into their mouths by pheromones.

	Rather a rare type of adaption, and more closely related to
the Angler Fish feeding mechanism than to marine plankton eating.
>
>2. There certainly no shortage of marine plankton eaters. They are all
>   slow swimmers. Hence by symetry an airial plankton eater should be a
>   week flier.
>
>3. A plankton eater would not have to land very often. Possibly only to
>   breed. There are I beleive some species of marine birds which stay aloft
>   for years at a time.
>
>4. Reptiles require less energy per unit mass. Hence a lower density
>   of insects is needed to support a reptilian plankton eater than an
>   avian one.
>
>5. Point 4 again only gliders require less energy than fliers. Hence even 
>   a lower density of energy is required.
>
>6. Insect eating is certainly one of the main preoccupations of
>   modern fliers such as Bats, Birds and Insects.
>
	Well, this sounds very nice and logical, the flaw is that
insects(your airial plankton) are themselves *active* flyers rather
than passive like marine plankton. Also observation of modern
insectivorous birds which eat "on the wing" shows that they are
*without* *exception* small, fast, active flyers(flycatchers,
nighthawks &c). (The Frogmouth eats while *perched*).

>So now the question.
>If the above is not true who was eating all the flying insects I suspect
>were quite abundant in the mesosoic?
>
	The small, fast, active-flying pterosaurs like Pterodactylus,
Rhamphorhynchus and thier kith and kin rather than the large gliders.
Just because *some* of the forms were large and "slow" doesn't mean
they all were.
-- 

				Sarima (Stanley Friesen)

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