Ostrich necks give clues to dinosaur flexibility

The familiar view of sauropod dinosaurs
reaching out for vegetation using their
long, graceful necks may not be entirely
accurate, say scientists.
A study of modern-day ostriches suggests the
ancient animals were probably quite stiff in
their movement.
Sauropod dinosaurs had a thick mass of
muscle in their necks and the researchers say
this would probably have restricted the range
over which the beasts could move their heads.
The study is published in Plos One.
Its authors say the findings have implications
for the way we display the dinosaurs in
museum exhibits and in the media.
Computer modelling that has been used to
simulate sauropod movements will not have
portrayed the lack of neck flexibility
accurately, the team adds.
For example, the BBC's landmark TV series
Walking with Dinosaurs modelled the neck
movement using the position of the vertebrae.
But this did not account for the effects of soft
tissues like muscle and cartilage, which this
new study tries to incorporate by looking at
ostriches.
The team, led by Matthew Cobley from the
University of Utah, US, has shown that muscle
mass reduces the maximum flexibility of
ostrich necks.
The researchers measured the flexibility of the
flightless birds with all their muscle tissue
intact, and then slowly removed the muscles to
test how this changed the situation.
As they are the largest birds to exhibit
elongated necks, with vertebrae and
musculature broadly comparable to those of
sauropods, ostriches provide useful insights
into the past.
"Previous studies looked at the skeleton on its
own and the assumption was that flexibility is
limited by the bones of the skeleton, but our
study shows it's actually the soft tissue around
it," said Mr Cobley.
He added that computer modelling of any
biological system needed to be "ground-
truthed" before it was accepted by the
scientific community and presented to the
public.
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