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Re: Tyrannosaur age-population distributions

On Sun, 16 Jul 2006 13:32:55 -0400 Graydon <oak@uniserve.com> writes:
> On Sun, Jul 16, 2006 at 09:27:41AM +0000, Phillip Bigelow scripsit:
> > On Sun, 16 Jul 2006 08:46:02 -0400 Graydon <oak@uniserve.com> 
> writes:

> > > Were tyrannosaurine packs accreted on a basis of purely social
> > > bonds?

> > Heh.  Keep in mind the size of a tyrannosaurid's brain.  *IF* pack
> > activities occured, was it instinctual?  Yes.  Instinct usually 
> drives
> > behavior in non-mammalian vertebrates.  But was it "social" 
> behavior,
> > sensu lion prides?  Who knows, but I doubt it.

> I don't doubt it at all; chickens have social behaviour,
> and 
> chickens
> aren't any smarter than a tyrannosaurid and arguably less.

If you look at the E.Q. (encephalization quotient) for tyrannosaurids and
the E.Q. for chickens (and the E.Q.s for *all* living birds, in fact),
you will find that _T. rex_ adults lag behind all extant birds in the
Brainiac Department.

Robert Carroll's (1988) _Vertebrate Paleontology and Evolution_ textbook
has a graph showing the E.Q.s of the various relevent taxa.

Then there is the quantum jump between the E.Q. of extant birds and the
E.Q. of carnivorous mammals (like pack-forming animals.  Lions, for

_T. rex_ is "brainier" than crocs (and most herbivorous dinosaurs), but
that isn't saying much.  Most of _T. rex_'s brain volume was taken up by
the animal's sensory subsystems (olfactory lobes, and to a lesser extent,
its optic lobes).  But for complex social interactions, a larger cortex
is needed and _T. rex_ just doesn't measure up in that Department.

Why do chicken coops only have two doors?
Because if they had four doors, they would be chicken sedans.
(as told to me by my neighbor's son)