Re: gigantism as liability

[john bois <jbois@verizon.net>]

----- Original Message ----- 
From: "John Scanlon" <riversleigh@outbackatisa.com.au>
To: "'john bois'" <jbois@verizon.net>; <dinosaur@usc.edu>
Sent: Monday, November 17, 2008 6:32 PM
Subject: RE: gigantism as liability


> A factor not apparently mentioned so far is likely synchronization of
> breeding within regional populations and among species, as with sea 
> turtles
> (where 3 or 4 spp. may hit the same nesting beaches at the same time). 
> This
> increases the odds of survival for any individual young by swamping the
> predator population, and particularly (if nesting events are far enough
> apart, most likely annual but potentially even longer) preventing a large
> population of specialist (hence efficient) nest- and juvenile-predators 
> from
> arising.

Success for this strategy is highly conditional. In turtles, parents leave 
the nest and so are not continuously advertising its presence. A significant 
proportion of their predators only have a small window, i.e., the scramble 
to the water. For birds, nesting remotely from most predators is essential 
for colonil nesting species. And then, compared with sauropods, incubation 
time is short as is the time to achieve relative predator immunity, i.e., 
fledge.
So, for sauropods to successfully employ such a tactic I think you would 
have to argue they buried their eggs and left them, or, that they migrated 
to places their predators couldn't reach.