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Re: nesting strategies




On Sun, 7 Sep 1997, Dann Pigdon wrote:

> John Bois wrote:
> > I think there is general agreement that dinosaurs could not burrow.

>       Penguins, sheer waters ("mutton birds"), puffins, even a 
> species of owl nest in burrows. Although some may not be able
> to physically burrow, they can take advantage of abandoned burrows
> of other species, or use natural hollows. Given the preservational
> bias against small dinosaur species (a general statement, I know.
> The reverse is true of Dinosaur Cove in Australia), there may well
> have been small species that had fore or hind limb structures suited
> to digging.

Yes.  I take it back.  There may well have been this sort of limited
burrowing ability in smaller dinosaurs.

>       I wouldn't suggest there were white dinosaurs that found
> camoflauge in the snow. Rather I was just giving an example of
> an extant creature that leaves its well camoflauged young by
> itself while it goes off to forage, or draws predators away.

I know that.  But I have been trying to argue that all or most of the
examples cited for this strategy are inapplicable to non-avian dinosaurs.
As I said earlier, I appreciate the examples, they are good ones.  

>       Any discussion of dinosaur behaviour will only be based
> on indirect and ambiguous evidence. Bones, footprints and nests
> are not behaviour. This leaves the scope for arguements and
> theories wide open, most of which are probably going to be about
> things we could ever hope to test anyway.

Well, I just think this is a too limited view of the function of science.
Some things may be assumed to be true even though we can't test them.
Here are some:  Non-avian dinosaurs had red blood.  Our sugar drive
evolved in order that we would seek out that valuable resource.  Our sex
drive evolved so that we would be more likely to reproduce.  While
Natural Selection was once believed to be impossible to test,
reasonable men and women saw its truth nevertheless.
Besides, I really don't think the position I am trying to argue is very
radical.  Indeed, its assumptions _are_ open to test, i.e., we may in time
get a better idea of dinosaur nest location--were they generally in the
open (as all our current evidence suggests--notwithstanding preservational
bias)?  Were dinosaurs losing their smaller members over the cretaceous?  
If these are borne out it would be prudent to claim the following:
inasmuch as non-avian dinosaurs were generally large animals, they were
relatively less likely to be able to conceal their nests.  We find no
concealed nests.  And, inasmuch as non-avian dinosaurs had no radical
differences between themselves such as the ability to swim great distances
ot eh ability to fly, they were relatively less able to site their nests
away from their predators (other dinosaurs, varanids, terrestrial crocs,
for example).  None of this is to say that some dinosaurs couldn't swim to
remote islands, or conceal their nests, only that they were relatively
less likely to do so.  All this being true, they were relatively _more_
likely to engage in strategies of defence.
        In short, if they couldn't hide and couldn't run, they had to
defend.  It might be possible to make this claim one day.  And I'm going
outside right now to look for evidence.