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Re: dino hineys and much more (was mammal mystery)
> Elephants and hominids are biding their time, so to speak, until the
> inevitable: Just wait until the next large asteroid impact. Extinction
> has been the historical fate of all but two genera of elephants and all
> but one genus of hominid.
And of all of the dinosaurs and of all of the trilobites and of all
pelycosaurs and of all . . . . Vulnerability to extinction does not
equate to the success of a genus, in my opinion. All species eventually
become extinct, and that extinction does not necessarily equate with
But elephants and hominids aren't doomed >because< there
> are no mouse-size elephants or hominids. They're doomed because, unlike
> small, fecund animals, elephants and hominids are unlikely to give rise to
> new species quickly enough in response to a relatively rapid unfavorable
> environmental change. Even if there >were< mouse-size elephants and hominids,
> the larger members of those families would still be doomed when such an
> environmental change occurred. They would, however, likely be replaced by the
> larger descendants of their smaller relatives once the environment
Completely true, but I wonder about the context of this statement.
Was the Mesozoic the "Age of Shrews" because those dinosaurs that were
exploiting just about every econiche failed to realize that they should
have sat tight in burrows eating grubs, breeding wildly and waiting for
the next asteroid . . . and then the next . . . and then the next . . . ?
Do hundreds of millions of years of successful radiation (leading to
"dooming" specialization) mean that the dinosaurs were not successful
during those same hundreds of millions of years? I don't think that you
really believe this. Of course I agree that many animals are victims of
their success in the final analysis, but that observation doesn't really
have a place in a discussion of the relationship between Mesozoic mammals
and the dinosaurs.
Let's not forget that the origin of this post was the question "why were
mammals small and dinosaurs large?" Can anyone seriously argue that the
mammals "chose" to be small because they were little versions of 1950's
paranoids, building their little bomb shelters because they "knew" an
asteroid was coming? Or that the dinosaurs shrugged, their "primitive"
bipedalism handicapping them from taking the coveted burrowhole, and
sadly trooped off to settle for the rest of the terrestrial world? Of
course not! Animals radiate into every niche they can. Mammals were
kept in a few marginalized niches because the dinosaurs were better
suited at that time to the multitude of other niches. Note also that
those clever furballs either forgot their tininess strategy when the
dinosaurs were gone or someone forgot to tell Indricotherium.
1) To the original poster: don't forget that there were many small
dinosaurs too. Compsognathus and others were very small -- smaller than
many of today's mammals. Those small dinosaurs may have eaten the little
mammals when they could catch them, possibly aided by the ability to
catch prey with their forelimbs.
2) As for questions about the "warmness" of mammals' little hineys (some
took this to suggest that dinosaurs had cold hineys, and were outraged),
the jury is still out on dino hineys. Until we know more about their
hineys, we can only speculate. But we know that mammal hineys are warm
(mine is, anyway).
Ta for now --