How It Works-Book Of Dinosaurs

Nests & eggs

28

All dinosaurs laid eggs

Dinosaurs all reproduced by laying eggs like

modern-day birds, and some of the hatchlings were

thousands of times smaller than the full-grown adults.

17

Herds of

dinosaurs

were fossilised

together

At a bonebed in

Alberta, Canada, at

least 27 ceratopsids

with frilled heads and horns

were found buried together.

29

Some dinosaurs cared

for their young

Adult Psittacosaurus have been found alongside the

fossilised remains of their young, and the bones of

older babies have been found in the nests of

Maiasaura, indicating that they probably helped to

raise their young.

30

The largest dinosaur

egg was over 60cm long

The largest dinosaur eggs were found in Mongolia in

the 1990s, and measured around 45cm (17.7ft) across.

Compared to the size of the adults, they are still

surprisingly small.

31

Some of the best dinosaur

fossils are babies

A 113-million-year-old fossilised baby dinosaur found

in Italy still contains traces of preserved soft tissue,

including intestines and tail muscles.

27

Ceratopsians had

horned faces

The most famous ceratopsian is

Triceratops, but there were other

dinosaurs with horns and frills. These huge

herbivores started to appear around 160

million years ago, and it is thought the frill

was used as protection against predators,

to impress potential mates and as a

radiator to get rid of excess heat.

26

Dinosaurs had feathers

Despite what you might see in textbooks, museums

and even in this bookazine, we now know that most dinosaurs

were not all scaly and bald. We have known for a while that the

two-legged theropods had feathers, but in 2014 a very

distantly related beaked dinosaur found in Siberia was also

found to have feathers, suggesting scales were replaced early

in dinosaur evolution.

21

The Sea level

dropped as the

dinosaurs went extinct

At around the time the dinosaurs went

extinct, the sea level fell by 150m (492ft).

20

Big bodies kept

dinosaurs warm

This process is known as ‘thermal inertia’.

The larger the body of an animal, the lower

the surface-to-volume ratio – preventing

heat escaping from the skin.

32

Baby dinosaurs

grew rapidly

Sauropods like Diplodocus weighed a tiny 5kg (11lb) at

birth, and grew to 10,000 times their size within just

30 years. Fossilised embryos show sauropod bones

fi lled with blood vessels, bringing nutrients to allow

rapid growth.

33

There are two main

types of dinosaur egg

Dinosaur eggs can be divided into two main

categories – spheroidal and elongated. Rounder eggs

were laid by herbivores such as sauropods, while

elongated, bird-like eggs were laid by theropods.

34

Oviraptors didn’t

steal eggs

The name ‘Oviraptor’ means egg thief, but these

dinosaurs weren’t criminals. They were actually

devoted parents, and fossilised nests found in Mongolia

show they arranged their eggs in spiral layers.

16

Ankylosaurus was one of the

last surviving dinosaurs

These heavily armoured dinosaurs had clubbed

tails, weighed over 4,000kg (8,818lb) and

were covered in bony plates. They were

extremely tough, and no predator could

tackle a full-grown adult.

19

Pterosaurs

weren’t dinosaurs

Pterodactyls are the iconic fl ying dinosaurs, but

they weren’t actually dinosaurs at all. Dinosaurs

were all land animals. Quetzalcoatlus, the largest

pterosaur of all, had a 12m (39ft) wingspan,

making it the largest animal that ever fl ew.

Sauroposeidon was

about three times

taller than a

giraffe

18.5m

Sinornithosaurus

Early Cretaceous

China

Styracosaurus

Late Cretaceous

Canada

© Corbis; Thin k stock; Nobu Tamura; Michael B. H

DID YOU KNOW? (^) The Cuban bee hummingbird is the smallest living descendant of the dinosaurs, measuring just 5cm (2in)
FACT 18