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Re: new boook on functional morphology
On Fri, 19 Jan 1996, Stan Friesen wrote:
> From: JCMcL <firstname.lastname@example.org>
> > > That aside, it is still true the main use of the horns was probably
> > > contests *within* the species. Even well-armed herbivores prefer
> > > to run away from predators rather than fight.
> > Just a thought. I have less confidence than Stan in my understanding of
> > the ceratopsian behavior patterns, but know that they shared their world
> > with many predators that could easily outrun them.
> I would not say I am that certain. I just find the old, traditional
> over-emphasis on fighting predators so powerful that I want to make
> sure of countering it.
> > A formidable and aggressive familial defense, a prickly ring of adults,
> > seems fairly likely to me.
> To me, too - when overtaken with young present. Indeed, even antelope
> that do not use this group defense will stand and fight to protect
> the young. I have seen film of a single wildebeest female charging
> hyenas that were attacking its calf. However, that same wildebeest
> would run from the hyenas if the calf were not present.
> What I am opposed to is the old picture of a solitary Triceratops
> having a duel with a Tyrannosaurus. I doubt that a Tyrannosaurus
> would confront a healthy adult Triceratops from the front under
> normal circumstance.
I rather doubt that a healthy Triceratops could be found in a solitary
condition. I also doubt that anything hunting such animals would do so
in a solitary manner.
> Note, in one reference I have a case is made that dinosaurs, even
> the large ones. were r-selected, rather than K-selected like large
> mammals. If this is really so, than it may never have been the case
> that protecting young was economically viable (individual young are
> not as valuable to a r-selected animal, and so are less often protected).
> The peace of God be with you.
My own suspicion is that, as in, say, ostriches, the dinosaurs were
R-selected as eggs and K-selected as chicks (or whatever baby dinosaurs
are called - saurlets?).
In a world full of small fast predators, an unprotected ceratopsian
I've said earlier in these postings, would be topsy mcnuggets to such
predators. Small, fat, squishy. MMMMmmmmmm! If the parents simply
abandoned such tasties to Cruel Father Nature, the ceratopsians would
likely have been a short-lived phenomenon.
My suspicion is that herds of ceratopsians were accompanied by packs of
swift light predators just waiting for 1) whatever the ceratopsians
flushed out of the bush, and 2) cute, undefended babies.
Only a suspicion, though. As I say, I lack the Certainty expressed in
so many of these postings.
Nonetheless, the straight-ahead horns and other offensive-defense
elaborations so common in the ceratopsian theme argue, at least to me, in
favor of some very impressive selective factor other than head-butting,
expecially since it appears in both sexes.
Oh, that marvellous certainty!