Page 28 - The Dinosaur Book and Other Wonders of the Prehistoric World (DK-Smithsonian)

Inside a

Introduction dinosaur Tail muscle Backbone

Although soft tissues of
animals’ bodies seldom

fossilize, we can still
figure out what dinosaurs were Tyrannosaurus
like on the inside. Dinosaurs were
vertebrates, and all vertebrates
share the same basic body plan,
with powerful muscles connected Leg muscles ❯ Big
to a jointed skeleton and internal dinosaurs like this
Tyrannosaurus had
organs that included a heart, lungs, huge muscles. Heat
stomach, intestines, and brain. generated inside the
Dinosaurs were once thought dinosaur’s body kept
the muscles warm for
to be cold-blooded, lumbering maximum efficiency. Thigh muscle
reptiles, but we now think that
many were as quick-witted and
active as birds, and some may
even have been warm-blooded.

Dinosaur features

The brain of a dinosaur The closest living relatives Air sacs (blue) stored air
like Citipati was adapted for of extinct dinosaurs have and pumped it back
sharp senses, not intelligence. four-chambered hearts. through the lungs (red).

Brain The brains of extinct Heart Pumping blood around Lungs Fossil evidence shows
dinosaurs were relatively small, the body of a giant dinosaur that dinosaurs had lungs
and some were tiny. Most would required a powerful like those of modern birds,
not have been as intelligent four-chambered heart—similar which are more efficient
as modern birds. to a human heart, but a lot bigger. than the lungs of mammals.
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