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Re: Phorusrhacids killing large mammals in National Geographic Channel

> It's generally a bad habit to get more than one step of implication away
> from a nice, solid fact, even so.

For a science-minded person in a formal setting, or a setting where
one could easily be misinterpreted or taken out of context, I agree.
Otherwise, I don't think there's much harm in casual banter between
educated individuals. ; )

Specificity and clarity about *when* one is speculating, and to what
degree, is just generally useful though. That I do habitually.

> Well, no one can, that's part of the problem.

I guess I meant even the broad outline of the ecological principles
involved, in my case. I think.

> Historically, yes, there was at least a lowlands/uplands seasonal
> migration going on.  Pre-human-settlement patterns are going to be
> mightily difficult to reconstruct.

Did not know that. And I can see how having a billion people peppered
across the forests and the Terai would impede research into the
pristine state . . . yikes.

> The North Amercian list is longer than either the India or Africa list
> -- short faced bears, grizzly bears, polar bears, black bears; three
> species of wolves ("buffalo" wolves, timber wolves, coyotes); lions,
> cheetah, puma, jaguar; this may -- though I do not know how to go about
> proving this -- be correlated with scale and scope of migrations, which
> are substantially unimpeded north/south in NorAm.

Well, I dunno if I'd count polar bears, since I'm pretty sure they
didn't/don't really coexist with most of the rest, and I think I'd
class coyotes on the jackal side of the spectrum instead of with
wolves, but yeah, it's an impressive list. Especially when *Smilodon*
and *Homotherium* are factored in, too.

 . . . Shouldn't the "buffalo" wolf be a subspecies? My understanding
is that Eastern wolves are genetically closer to red wolves, and so
it's they who would appear to be a distinct species (*C. lycaon*). And
of course there would have been *C. dirus* as well.

If we're talking about relatively recent ecosystems, we should
probably also be including *Meganteron*, *Homotherium*,
*Pachycrocuta*, Eurasian jaguars, and maybe even *Dinofelis* and
*Agriotherium* in the discussion of Old World predator guilds - not to
mention *Chasmaporthetes* across Africa and the Holarctic.

Stupid Holocene extinction.

> Of course, this also raises the question of how you got T. rex and only
> T. rex in what looks like a herbivore-diverse migratory environment.

Its awesome was too overwhelming.

More seriously, what truth is there in the idea that Hell Creek
represents an impoverished, somewhat cooler environment with a larger
number of individuals in a smaller number of species? Could it be a
post-turnover ecosystem in which a few weedy species have yet to