[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: dino-lice



  I would like to note that no animal eats eggs of any sort exclusively, up to 
and including the African egg-eating snake, *Dasypeltis* spp.; their diet also 
includes various lizards, small, small mammals and even other snakes. Virtually 
all snakes are opportunistic carnivores. Egg-eating as a specialization, 
however, does seem to drive morphology into a unique series of cranial, 
vertebral and muscular adaptations. *Oligodon* spp., the kukrisnakes, also 
possess specialized, broad rear-fanged teeth which adapt them to slicing open 
eggs (or really, anything else they bite) rather than simply puncturing.

Cheers,

Jaime A. Headden
The Bite Stuff (site v2)
http://qilong.wordpress.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion 
Backs)





----------------------------------------
> Date: Thu, 21 Apr 2011 22:19:01 -0700
> From: ron.orenstein@rogers.com
> To: augustoharo@gmail.com
> CC: dinosaur@usc.edu
> Subject: Re: dino-lice
>
> In tropical humid forests many species of birds breed over a good part of the
> year, with breeding recorded in every month, so egg-eaters could find nests
> throughout the year. However, with the exception of African egg-eating snakes 
> I
> cannot think of any vertebrate that eats eggs exclusively; most nest-robbers 
> are
> pretty opportunistic.
>
> Ronald Orenstein
> 1825 Shady Creek Court
> Mississauga, ON L5L 3W2
> Canada
> ronorenstein.blogspot.com
>
>
>
> ----- Original Message ----
> From: Augusto Haro 
> To: Ronald Orenstein 
> Cc: Dinosaur Mailing List 
> Sent: Fri, April 22, 2011 12:51:38 PM
> Subject: Re: dino-lice
>
> 2011/4/22 Ronald Orenstein :
> > A snail-picking adaptation might have led to a digit such as those in
> > alvarezsaurs, but why would the other digits be lost (they might be useful 
> > in
> > picking the animal out of the shell, for example)?
>
> May be, but I was thinking perhaps just a hook is optimal for
> snail-hooking, and that a similar development of other fingers may
> obstaculize it.
>
> > And why would such a
> > strongly-muscled arm be required?
>
> I think the forearm is strong relative to the size of the forearm, not
> so much relative to the size of the entire animal. Perhaps no more
> than in coelurosaurs with longer limbs. Before I wrote (but think it
> did not reach the list), that, so to speak, you choose the size of the
> pincer according to what do you want to pick. You would not use a
> pincer used to remove nails to extract a barely visible splint from
> your skin. So, perhaps if you want to break large termitaria, you use
> a large, strong forelimb, as in anteaters, pangolins, giant armadillo,
> etc. If you need to break something small, you may more economically
> use a smaller version of this. If you need to partially break a small
> thing (I was favouring perforating eggs for the thin snout to enter
> the hole, and to avoid its contents oozing), you need greater
> precision and this is given by a small version ot the same principle.
> For example, a large knife may be useful to get slices of a large
> vegetable, but may crush a small vegetable, where slices may be better
> made with a small knife.
>
> By the way, a question to you, which are an ornithologist: Do all
> birds deposit their eggs in the same season of the year in a given
> place? Because if this is true, then egg-eating (my favourite
> hypothesis) would not be so easy the rest of the year...
>
> > If the arms were used in foraging it seems more likely that they would have
> >been used as levers against considerable force
> > -- perhaps pulling apart some tangled mass of plant fibres or ripping into a
> > cycad trunk, for instance -- if they had access to some sort of trunked or
> > otherwise erect plant the difficulty of them having to stoop to ground level
> >to
> > burrow might not exist. Could the arms of alvarezsaurs be analogous to the
> > enlarged rooting teeth or tusks of some herbivorous mammals - given that 
> > tooth
> > modification was not on the cards for them - rather than to any limb 
> > structure
> > in another animal?
>
> These are possibilities... Indeed, they may not be mutually exclusive,
> because many structures can give many good uses, and perhaps looking
> for the one which was selected for implies dismissing the possibility
> that having something good for many uses, instead of specialized for
> the best performance at a unique task, in itself was something to be
> selected for.
>