Page 107 - World of Animals - Deadly Predators

Dinosaurs

THERIZINOSAURUS With powerful jaws, sharp
Therizinosaurus cheloniformis claws and a ferocious appetite,
Lifespan Unknown the Tyrannosaurus rex ruled as
Weight Up to 5 tons an apex predator

© Getty © Thinkstock

T-REX
Tyrannosaurus rex
Lifespan 30 years
Weight Up to 15 tons

Why so big?

The bodies of many dinosaurs had surface-area-increasing traits in large
pneumatic bones, which means that they mammals today, such as the sagging skin
Also known as the contained air sacs making them far lighter and huge ears of an elephant.
Scythe lizard, this
ferocious dinosaur compared to dense mammalian bones and The largest of the dinosaurs were,
used sword-like therefore easier to carry at a greater size. somewhat surprisingly, the herbivores, and
claws to keep Being cold-blooded reptiles also meant this is thought to be a consequence of not
predators at bay
that dinosaurs were able to increase their chewing. By swallowing a greater volume
body volume, reducing their comparative of plant material they could consume far
surface area without upsetting their body more in a day, and without the heavy teeth
temperature. Were hot-blooded mammals needed for mastication they could lift their
to grow in the same way they would heads higher, developing longer necks and
likely overheat, which is why we see many reaching more food.
One such threat to the mosasaurs was
the Cretoxyrhina, an extinct species of
The diet and anatomy
mackerel shark, which, at 7.6 metres (25
of dinosaurs living in the
feet), was more than capable of slicing Jurassic period was the key
through Mosasaurus flesh and bone using to their immense size
its razor-sharp teeth and forceful bite. We
know this animal preyed on mosasaurs
thanks to the fossil evidence provided
by sections of mosasaurs that have been
hacked off, swallowed, partially digested
and then regurgitated.
The other marine hunters dominating
the oceans at this time were the
plesiosaurs. These marine reptiles
boomed in the Jurassic period, with
over 100 species being named to date,
growing to sizes ranging from 1.5 to 15
metres (4.9 to 49.2 feet). Their broad, flat
bodies with flipper-like appendages and
long, paddle-like tails made them highly
adapted at hunting in the water. They are
believed to have been ambush predators,
giving chase to escaping prey and using
their long necks to capture swerving fish.
It’s also thought they may have been able
to ambush prey by sitting on rocks by the
water’s edge, dunking their heads in to
capture unsuspecting fish. They had very © iThinkstock
large heads with sharp, outward-facing
teeth, perfect for ripping apart their food.

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