At up to 12 meters long and weighing as
much as two tons, the Allosaurus was one of the
fiercest dinosaurs of the late Jurassic Age. But
its slender teeth and sometimes narrow jawbone
have left scientists puzzled as to how the
Allosaurus managed to hunt prey successfully.
Emily Rayfield, of the University of
Cambridge's Department of Earth Sciences,
performed a detailed study of Allosaurus's skull
using a new technique, employed more usually by
engineers, called Finite Element Analysis, to
build up a picture of how strong the Allosaurus
skull was. Her results are published in
Nature today.
The technique involves first building a digital
image of the structure to be tested. Miss
Rayfield's team used a CAT scanner on an existing
dinosaur fossil. She then calculated the elastic
properties of the bone, by modelling it on modern
cow bone, and worked out how much muscle would
have covered the Allosaurus's head.
By estimating how hard those muscles could
contract, Miss Rayfield was able to build up a
picture of how powerful a bite the Allosaurus had.
"We worked out that the strongest bite at a
single tooth bite would probably have been in the
region of 200 kgs in weight," explained Miss
Rayfield. "That makes its bite about four times
weaker than a Tyrannosaurus Rex, or an alligator.
"Our research also showed, however, that the
Allosaurus had an extremely strong skull. So while
its bite force was weak and its teeth were slender
and narrow, the skull can withstand large impacts.
It's possible that, rather than using its jaws to
crunch bone as part of its feeding strategy, like
T.Rex, it used its powerful neck muscles and
strong skull to drive its teeth into its prey and
tear off chunks of flesh.
"Allosaurus may well have used this technique
to capture lighter, more agile dinosaurs -- but it
could also have ambushed heavier dinosaurs using a
hit and run-type strategy."
(Reference: "Cranial design and function in a
large therapod dinosaur" by Emily J Rayfield et
al. (Dept of Earth Sci, Univ of Cambridge), David
B Norman (Dept of Paleobiology, National Museum of
Natural History, Smithsonian Inst, Washington DC),
Celeste C Horner, John R Horner (Museum of the
Rockies, Montana State Univ, Bozeman), Jeffrey J
Thomason (Dept of Biomedical Sci, Ontario
Veterinary College, Univ of Guelph) published in
Nature on February 22.)
[Contact: Beck
Lockwood]
22-Feb-2001
