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Re: Dino nest parasitism



 Just saw the note requesting any cases of documented nest parasitism in
dinosaurs and I thought I'd add a field observation.

 About 8 years ago I was involved in field excavations at the Late
Cretaceous Devil's Coulee egg/nest locality in southern Alberta, Canada. I
was fortunate enough to locate a large hadrosaur (cf. HYPACROSAURUS) "nest",
with two parallel rows of eggs. These eggs are large (small beachball in
size), with a distinctive "pebbled" texture. I recall one row had about 6
eggs and the other was slightly longer with about 7 eggs. While digging
around the edge of this egg accumulation, I found at one end of the rows and
slightly lower in section, a well defined "cluster" of smaller, apple-sized
eggs with a different surface texture (smooth). Both the egg rows and egg
cluster were nearly touching and I did not think their joint circumstances
in the rock could represent the hadrosaur just missing the nest of a
previous egg layer of a different species, as the digging activities of the
hadrosaur would have disturbed, if not obliterated these smaller eggs. My
thoughts at the time were that this could be a case of nest parasitism, with
the hadrosaur eggs laid first, then the smaller eggs laid on the end and
slightly underneath the larger ones. But I considered this was a case of
nest parasitism with a twist: these were the eggs of small theropods who
would hatch out before the hadrosaurs and would thus gain a meal right away.
This interesting specimen has never been prepared.

 I have seen documentary footage of an extant turtle who sought out the nest
of an American Alligator, so she could also lay her eggs within the nest
mound and thus gain the protection of her eggs from the protective
alligator. I guess this is, in a way, nest parasitism (nest
borrowing/sharing?) too. After laying her eggs, the turtle waited for a
moment to escape the gaze of the mother gator, but in doing so was a bit
slow and was rigorously attacked by the protective alligator who proceeded
to repeatedly bite the shell of the turtle. After being bitten for a while,
the turtle escaped with no real injuries. While this "nest sharing" is known
to be true in real life, I have often wondered if this particular instance
was artificially recreated for the film. I see this kind of fakery stuff all
the time with film crews who come out to film our dinosaur digs.

 Perhaps the Devil's Coulee example I excavated is a similar scenario, with
a non-threatening species laying its eggs in a hadrosaur mound/nest for
protection. Maybe it was nest parasitism, who knows? I've always thought it
was a most curious egg accumulation that warranted a more detailed look.

 Best,

 Darren 
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FAEVUS QUAESITOR SCIENTIA                                  FODERE AUT CADERE

DARREN TANKE, Technician I, Dinosaur Research Program, ROYAL TYRRELL MUSEUM
OF PALAEONTOLOGY, Box 7500, Drumheller, Alberta, CANADA  T0J 0Y0 and:

Senior editor of: Annotated Bibliography of Paleopathology, Dento-Osteopathy
and Related Topics. 12,542 citations as of July 26, 1998.
For details, visit the bibliography homepage at: http://dns.magtech.ab.ca/dtanke
Can you help (translations, photocopying or financial support) with this
ongoing project? Email me at: dtanke@dns.magtech.ab.ca
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