![Geological Survey of Canada Geological Survey of Canada](/web/20061103045952im_/http://www.gsc.nrcan.gc.ca/esst_images/gsc_e.jpeg) Natural Resources Canada > Earth Sciences Sector > Geological Survey of Canada > Past lives: Chronicles of Canadian Paleontology
Past lives: Chronicles of Canadian Paleontology Eggs and embryos at Devil's Coulee
To paraphrase Samuel Butler's (1825-1902) famous epigram,
"A dinosaur is only an egg's way of making another egg"
![Reconstruction of the hadrosaur Hypacrosaurus egg and embryo from Devil's Coulee, southern Alberta. (Royal Tyrrell Museum Collections. Photo by BDEC (c).) Reconstruction of the hadrosaur Hypacrosaurus egg and embryo from Devil's Coulee, southern Alberta. (Royal Tyrrell Museum Collections. Photo by BDEC (c).)](/web/20061103045952im_/http://www.gsc.nrcan.gc.ca/paleochron/images/hypacro.jpg) Reconstruction of the hadrosaur Hypacrosaurus egg and embryo from Devil's Coulee, southern Alberta.
(Royal Tyrrell Museum Collections. Photo by BDEC (c).) |
Roy Chapman Andrews made many important fossil discoveries during the
American Museum of Natural History's expedition to the Gobi Desert in
the early 1920s but, in terms of public excitement, none surpassed the
dinosaur eggs he brought back. A celebrity auction in New York City
immediately established the monetary value of a single egg at $5000. But
the paleontological worth of dinosaur eggs is inestimably greater.
Dinosaur eggshell fragments are not common in the Cretaceous rocks of
Alberta. Unless they occur with abundant fossil clams and snails, which
buffer the calcite of the eggshells, these calcareous fragments tend to be
dissolved. The discovery of eggs, embryos and nests in the Two Medicine
Formation (Late Cretaceous, 75 million years old) at Devil's Coulee near
the Milk River in southernmost Alberta by a Tyrrell Museum field crew
headed by Phil Currie in 1987 started the study of dinosaur embryos in
Canada. This site proved to be amazingly productive. It yielded eggs, many
with embryos, some dinosaur hatchlings and nests -- one containing a
clutch of 8 eggs -- in addition to 20,000 isolated eggshell fragments. The
eggs are large -- nearly spherical and 20 cm diameter with a volume of
nearly 4 litres. The large embryos almost entirely fill the eggs and the
embryonic bones are sufficiently well preserved to identify the hadrosaur Hypacrosaurus.
At least nine separate nests were located in this area; evidence that Hypacrosaurus
nested communally. But the herbivorous dinosaur was not the only
animal using this site. Distinctive eggshell microstructure indicates that
birds nested here and, surprisingly, so did theropod dinosaurs.
During its growth from embryo to adult the weight of Hypacrosaurus increased
by 16,000 times -- evidence that they were active warm-blooded animals
with healthy appetites; definitely not sluggish creatures with slow
physiologies.
Further reading:
Carpenter, K., Hirsch, K.F. and Horner, J. |
1994: |
Dinosaur Eggs and Babies. Cambridge University Press. |
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