Re: [dinosaur] Fwd: Re: T. rex hunting Alamosaurus

[Dann Pigdon <dannj@alphalink.com.au>]

> Gregory Paul wrote:
>
> Sauropod nests are known and documented. They have the poorly organized
> structure typical of reptiles that immediately abandon their nests, they are
> not like the better organized nests of some dinosaurs and all known birds
> that at least care for the eggs (megapodes do not care for their
> hatchlings).

At least one paper (Hechenleitner et al 2015) has compared sauropod nests to 
extant megapode nests.

Several papers have come to the conclusion that some sauropod nests were 
excavated via scratch digging 
of the hind feet (Vila et al 2010, Fowler & Hall 2010, etc). That would suggest 
that sauropods both 
constructed and laid their eggs without being able to see what they were doing. 
Depending on how they 
covered the eggs after they were laid, that may have also been achieved without 
the aid of sight.

The poorly organised structure of some sauropod nests may have more to do with 
a very large animal 
attempting to build something relatively small (and with uncharacteristic 
delicateness) without the benefit 
of sight. 

Nest guarding behaviour isn't unheard of amongst non-theropod egg layers. Even 
squamates and tuataras 
do it. The degree of organisation of the nest structure may not be a good 
indicator of whether or not the 
eggs were guarded. Some behavioural adaptations don't leave tangible evidence 
behind, or if they do, can 
leave decidedly ambiguous traces. This is never more frustrating than when 
dealing with an entirely 
extinct lineage with no extant analogue.


One interesting aspect of Refsnider et al's 2009 paper on tuatara nest guarding 
is the conclusion that it 
may have more to do with protecting the nest from other female tuataras than 
for defence against egg 
predators. When good nesting spots are at a premium, female tuataras have few 
qualms about destroying 
the nest of another female in order to claim the nest site for their own eggs.


--
Dann Pigdon