How It Works-Book Of Dinosaurs

You’ll struggle to fi nd a

dinosaur without a tail.

This is because the

majority of dinosaurs used their tails

for two important roles: the fi rst

being balance and the

second being self-defence.

Large animals like the T-rex

and Diplodocus, thanks to

their skulls or necks,

were very top-heavy.

They needed long and heavy

tails to counterbalance this,

especially when running. Smaller

creatures such as Ankylosaurus

(left) used its tail when under attack,

evolving a large bony club at the end

which could bludgeon assailants.

One of the most telling links between

dinosaurs and birds is the Unenlagia, a

genus of theropod dinosaur from the

Late Cretaceous that in almost all

aspects, aside from fl ight, resembles a

modern bird. It was discovered in 1997

and to date two species have been

confi rmed – U comahuensis and U

paynemili – both of which share an

almost identical pelvic structure to the

early bird species Archaeopteryx.

Due to their

appearance in the

Jurassic Park fi lms,

the Velociraptor is

easily one of the

most recognisable of

all species. Importantly though, this

image of the Velociraptor is way off the

mark in terms of reality.

In contrast to the movie monster,

research evidence suggests that the

Velociraptor was actually a feathered

dinosaur under 0.6 metres (two feet) in

length, with colourful plumage used in

mating rituals and visual displays. The

species also had hollow bones, much

like birds, and built large nests to

protect their offspring.

The Velociraptor did impress in

ground speed, with it capable of hitting

39 kilometres (24 miles) per hour at top

speed and boasting amazing agility,

being able to change direction

incredibly quickly. It used this speed to

chase down prey, which largely

consisted of small to medium-sized

herbivores such as Protoceratops, and

then kill them with its nine-centimetre

(3.5-inch) retractable claws and

sharp teeth.

New research suggests that,

while sociable compared with

other carnivores, raptors

were not apex pack hunters,

with co-operative kills possible

but infrequent.

Tall tails

Unenlagia:

half bird,

half dinosaur

Velociraptors debunked

Massive scientifi c effort has been put

into identifying which creatures today

can trace their roots back to these

prehistoric beasts. One of the best

examples of this was the hunt for the

nearest living relative of the once-mighty

T-rex, undertaken by a research team at

the North Carolina State University in

2007. To go about this the researchers

sequenced proteins from a 68-million-

year-old T-rex tissue sample and, much

to their surprise, discovered that the king

of the dinosaurs’ molecules showed

remarkable similarity to the common

chicken and that its collagen makeup

was almost identical. So, at least for the

time being, the humble chicken is the

rightful ruler of the Earth...

Relatives in the modern world

Tail

The powerful tail was

tipped with bone

spikes and could be

swung at speed as a

form of self-defence

Legs

The front limbs were

far shorter than the

hind limbs, granting

its characteristically

arched appearance

Body

Due to Stegosaurus

being vegetarian, it

had a large stomach

perfectly adapted to

breaking down tough

plant matter

Skull
The skull was relatively
small, slender and low
to the ground, helping
it graze on low-growing
plants and vegetation

Plates

Two rows of triangular back

plates are believed to have

acted as key components of

a thermoregulatory system,

serving as organic radiators

One of the most recognisable
dinosaurs of all time, the
Stegosaurus – despite its herbivorous
nature – was a formidable opponent,
with its large muscular tail tipped
with lethal bone spikes. With a
length of about nine metres (30
feet) and a typical weight of two
to three tonnes, the Stegosaurus
had a rounded body and heavy skull.
Stegosaurus lived in the Late Jurassic
period around 150 MYA.

Stegosaurus

THE PREHISTORIC WORLD

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