Re: dino-lice

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

On Tue, Apr 19th, 2011 at 9:05 AM, Vivian Allen <mrvivianallen@googlemail.com> 
wrote:

> They're not exclusively scavengers, are they? Maybe I'm missing the point.

One might compare alvarezsaurs to Maribu storks (albeit flightless versions). 
Well adapted to 
scavenging, but still capable of taking all manner or live prey when the 
opportunity arises.

Perhaps the reduction in the size of the forelimbs allowed alvarezsaurs to 
squirm their way even 
further up the cloaca of a carcass, to get at more of the offal inside. If a 
big-armed theropod like 
Velociraptor (which also had a narrow head and long neck good for carcass 
probing) tried to reach 
the intestines of a thick-skinned carcass via the cloaca, their large shoulders 
might have restricted 
their reach. Whereas the small shoulders, narrow chest, and tightly folded 
vestigial forelimbs of an 
alvarezsaur may have allowed it to probe a cloaca right up to its hind legs. 
The sturdiness of their 
small forelimbs might have also helped wiggle them free again - or perhaps they 
used them to tear 
the carcass 'a new one' (or at least a wider one) to allow the chest to follow 
where the narrower 
neck and head could more easily go.


> On 19 April 2011 00:02, Dann Pigdon <dannj@alphalink.com.au> wrote:
> 
> > On Tue, Apr 19th, 2011 at 8:37 AM, Vivian Allen <
> > mrvivianallen@googlemail.com> wrote:
> >
> > > On 18 April 2011 23:23, Dann Pigdon <dannj@alphalink.com.au> wrote:
> > >
> > > > On Tue, Apr 19th, 2011 at 4:01 AM, Augusto Haro <augustoharo@gmail.com
> > >
> > > > wrote:
> > > >
> > > > > It may be, although I suspect that dinosaurs with great olfactory
> > > > > acuity as tyrannosaurids and dromaeosaurids may reach it before and
> > > > > open the carcasses then. I would also expect more laterally
> > compressed
> > > > > unguals, dromaeosaur-style, if expecting carcass hide-cutting.
> > > > > Besides, I do not see in the shout of alvarezsaurs much indication of
> > > > > carrion-eating, such as recurved beak or teeth...
> > > >
> > > > Who needs to pierce hide when you've got a narrow head and long neck,
> > and
> > > > nature has provided
> > > > a ready-made access chute for reaching the intestines? Some of the
> > smaller
> > > > vulture species that
> > > > lack the strength to pierce hide opt for the sphincter option.
> >
> > > Sorry to trot out the obvious argument, but how would a non-flying
> > obligate
> > > scavenger find meals quickly enough to compete with opportunistic
> > > scavengers? (i.e. every carniverous species withing detection range of a
> > > carcass). Anyways, my vote would also be for atrophied, unless there is
> > > compelling evidence otherwise.
> >
> > You could ask the same of jackals. They compete against flying scavengers
> > (vultures, storks)  and
> > larger scavenging carnivores (lions, hyaenas). Being small and agile can
> > allow a scavenger to dart
> > in, grab a piece, and dart out again if the carcass already has an 'owner'
> > (or several).
> >
> > --
> > _____________________________________________________________
> >
> > Dann Pigdon
> > Spatial Data Analyst               Australian Dinosaurs
> > Melbourne, Australia               http://home.alphalink.com.au/~dannj
> > _____________________________________________________________
> >
> >
> 


-- 
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
_____________________________________________________________