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Re: Nocturnal crocs?




On Fri, 24 Aug 2001, David Marjanovic wrote:
>         Just curious -- are you trying to explain the extinction of
> dinosaurs by mammals eating their eggs? :-o

Dinosaur diversity was probably not affected much at the K/T
(inasmuch as bird diversity making it through may well have
been greater than non-avian esxtinction).  Instead, the K/T represents the
death of a niche--that filled by large oviparous species in terrestrial
locations.  This niche has been practically empty ever since!  Today,
mammals and birds (and, to a lesser extent, reps) appear to be the agents
keeping that niche empty.  The question then becomes: at what time did
this first start being the case?  
Mammals of the K/T in the western interior had reached the size where they
_could_ have preyed on nests and hatchlings (judging by comparisons of
today's pred and prey ratios, e.g., a hairy armadillo preying on rhea eggs
is broadly comparable to a Didephodon preying on a dino egg).

> > Small jackals today
> > cannot approach ostrich nests in the day time but have no trouble at
> > night.
> 
> Really? I thought the male sits on the nest at night?

Whichever sex it is, it is driven off the nest by jackals taking advantage
of their superior night vision.1