Re: Good mother dinos

[Tracy Monaghan <monaghan@cac.washington.edu>]

On Fri, 4 Nov 1994, Tom Holtz wrote:

> >>> 1) How can you tell from fossilized bones whether any particular
> >>> species of dinosaur was a "good mother" or cared for its young?
> 
> >In the case of Maiasaura, there is evidence that when the young
> >hatched, their long bones weren't fully ossified, so the animals
> >couldn't support their own weight.  The obvious inference is that food
> >had to be brought to them until they outgrew that condition.
> 
> One complication of this bit was the presentation of Dave Unwin (U. of
> Bristol, UK) at the 1993 SVP.  He showed that, based on embryo-to-egg ratio
> found in modern birds and reptiles, the Maiasaura "hatchlings" are actually
> the proper size for a late-stage non-hatched embryo.  He did go on to point
> out that this doesn't disprove parental care in the Dinosauria, but it does
> take a way one previously important piece of evidence.
> 

I don't follow this last point.  Is the implication that the "hatchlings" 
were actually someone's snack-ling?  Or that Maiasaura may have only 
stuck around until the blessed moment, leaving the kids on their own 
after they hatched (hatch-key kids?)


Tracy <monaghan@cac.washington.edu>
Information Highway Worker
University of Washington
Seattle, Washington