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Re: Sauroparenting



On Sat, 20 Dec 2003 zone65@bigpond.com wrote:
> The question of how or if sauropods cared for their young is extremely 
> interesting, if vexing. I imagine the size difference between newborn 
> and adult would be the greatest in terrestrial vertebrate history? 
> Notwithstanding the grub-like young of marsupials...
> 
> How could the adults even see their young, in most circumstances? The 
> trampling possibility is a very real one, I think... this is tricky.

Depends on how precocious the young were. They may have been able
to look out for themselves.

> > wrote:> From: owner-dinosaur@usc.edu
> > [mailto:owner-dinosaur@usc.edu]On Behalf Of
> >> Ken Carpenter
> >> I would take strong exception to this, noting that
> > the "evidence"
> >> for parental care in the Dinosauria (even Jack's
> > Maiasaura) is
> >> very weak and based mostly on inferences and
> > assumptions.
> >> What
> >> evidence there is indicates that the smallest
> > footprints in track
> >> sites are half- or more adult size. There are NO
> > baby tracks with adults.
> >
> > Doesn't it make sense that the infant-to-juvenile
> > sauropods and other very large dinosaurs would avoid
> > moving with groups of adults?  The chance of trampling
> > would be too great I think.  But this doesn't preclude
> > any parental care, especially with how fast they may
> > have grown.  Many modern animals care for their young
> > for some time seperately from the main group until
> > they are better able to move.  Of course, these are
> > mammals whose young are much closer in size to the
> > adults than dinosaurs but it does show that the parent
> > can leave the group to care for their young.
> >
> > However, doesn't the "spongyness" of the leg bones of
> > some types of infant dinosaurs make parental care a
> > necessity?  Not to mention the distance between nests
> > being approximately equal to the size of Maisaura
> > adults.  I wasn't aware of any serious rebuttals to
> > the evidence for Maisaura acting like their namesake.
> >
> > Not to mention that parental care becomes more
> > widespread among living animals every year it seems.
> > Many creatures once thought to not care for their eggs
> > and young are being found to.  All living crocodilians
> > and birds care for their young for varying periods in
> > varying ways (except for some kinds of mound nesting
> > birds in Australia and New Guinea which don't do
> > anything other than provide very large self-heating
> > nests for their young).  Even Cuckoos devote quite a
> > bit to their young in terms of selecting other parents
> > for them.
> >
> > Many monitor lizards are now being found to care for
> > their young in amazing ways.  Several species incubate
> > their young via termite mounds, some of these having
> > the mother even come back to dig them out when they
> > hatch.  Komodo Dragons also guard their nests until
> > near hatching time.  Many amphibians care for their
> > eggs and young, even the giant salamanders of China
> > and Japan.  I saw an African Bullfrog on one show that
> > was shown digging a small trench through the mud to a
> > nearby pool of water to save dozens of tadpoles that
> > were in an evaporating puddle.
> >
> > Every vertebrate (and many invertebrate) group has at
> > least some members that exhibit parental care of eggs
> > and/or young (unless you consider sharks to be
> > vertebrates and not in remotely the same group as
> > other fish).  So with all due respect it seems
> > inconceivable to me to think that dinosaurs did not,
> > to varying degrees.  It seems that most any animal
> > that can't care for itself effectivey at birth has to
> > have some parental protection.  And many animals that
> > can care for themselves at birth (crocodilians) still
> > exhibit parental care.
> >
>