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

Re: Bird/hibernation/torpor

On Mon, 31 Mar 1997 dis@gj.net wrote:
> Gobiconodon is early Cret. 


> Also remember at cat sized that means they 
> could eat small eggs some were as big as melons.

This assumes that the only method of eating eggs is to wrap teeth around
them and bite down.  I know it's speculative, but speculating, isn't it
possible that smaller mammals could gnaw like rats (a rat I once knew
gnawed a chicken egg, and ate shell and all--all I had to do was put a pin
prick indent in the egg to get it started).  Another method, practiced by
jackals on ostrich eggs, is to bang eggs on each other.  

> Cretaceous mammals were not very smart, Troodon would have been much 
> smarter. Mammals got smarter over time. 

Beyond the difficulties of scaling brain/body mass, _and_
anthropomorphizing (my use of the word "smarter"), animals are smart in
different ways.  A squirrel is phenomenally smart at solving maze
problems, for example.  Troodon would have been smart in its
species-specific way.  I imagine late-cretaceous mammals to be strong in
areas that dinosaurs were not: getting about at night; finding refuge in
small places (though I am told there is _no_ evidence of burrows in or
near dino nests!); and a greater ability to _plan_ (I get this from
McLoughlin's _Synapsida_ which relates this faculty to the devt. of the
neopallium, an "inner space" where "sequences of discrete behaviors were
strung together like beads to bridge the gap between odor-of-prey and the
prey itself...So appeared the first purposeful use of a sense of time and a new
awareness of consequences.")    

> I seriously doubt we've missed any large relatively common mammals. We 
> screen wash and get hundreds to 10,000 of tiny mammal teeth. All you 
> need is one tooth to ID a mammal.

Dated by fossils, most mammal lineages began at or soon after the K/T.
Molecular clock evidence suggests their presence well _before_ the K/T.
And Archibald finds protoungulates something like 85mya meaning that
probably atleast this group had diverged by then.  Shouldn't we then now
be searching for proto-carnivores, proto-rodents.
>       I drive botanists nuts but I cannot find anyother way to come up 
> with enough plants to feed all the animals in the Morrison. Most 
> gymnosperms do not take grazing well.

Then allow me to drive you nuts with one last question.  I think you are
saying that dry-tolerant ferns were the major fodder for open-country
dinosaurs in the late cretaceous.  Do you think they could support the
biomass that modern savannah grasses can, and do you think theirrange was
as broad as the grasses?