Dinosaurs had respiratory system like birds -study

LONDON (Reuters) – Dinosaurs may have been fierce predators
but they had a respiratory system similar to modern birds such
as the sparrow, scientists said Wednesday.

Ancient beasts such as the mighty Tyrannosaurus rex were
thought to have had lungs similar to crocodiles but researchers
in the United States have discovered the creatures had more in
common with birds than reptiles when it came to breathing.

“The pulmonary system of meat-eating dinosaurs such as
T.rex in fact shares many structural similarities with that of
modern birds, which from an engineering point of view, may
possess the most efficient respiratory system of any living
vertebrate inhabiting the land or sky,” said Leon Claessens, of
Harvard University in Massachusetts.

Claessens and Patrick O’Connor, of Ohio University’s
College of Osteopathic Medicine, compared dinosaur bones in
museums in the United States, Germany and England with modern
birds. They looked at how the skeleton related to the air
system in areas such as the neck and chest.

The researchers found that dinosaurs had a respiratory
system with the potential to support elevated rates of
metabolism. Although it is not identical to birds, O’Connor
said it is nothing like the crocodile system.

“What was once formally considered unique to birds was
present in some form in the ancestors of birds,” he added in a
statement.

The study, reported in the science journal Nature, is the
latest to show similarities between dinosaurs and birds. Recent
research suggests some dinosaurs may have had feathers and
incubated their eggs.

Claessens and O’Connor said their research does not mean
dinosaurs were habitually warm-blooded. They believe the
creatures were somewhere between what scientists describe as
warm and cold blooded animals.