"Terrible plant-eating lizards"
From about 240 to 65 million years ago, dinosaurs
roamed the Earth. They were a group of reptiles (cold-blooded
animals who had a backbone), with scaly skin, and they laid eggs.
They were first called "dinosaurs" in 1841 by Dr Richard
Owen - the word is Greek and means "terrible lizard".
The earliest dinos had deadly, slashing teeth and claws which
they used to kill, and eat other reptiles. These were the carnivores
and they liked their meat.
"We've vegetarians now, thanks very much"
Among their prey was the new breed of herbivore
(plant-eating) dinosaurs which evolved from one or more breed
of predatory dinosaur during the Triassic Age (248-213
million years ago) and which over the next hundreds of millions
of years were to develop into huge, long-necked beasts, with immense
armoured protection against the carnivore predators.
"A little of both, please."
There was also a third group of dinosaurs which -
like the human beings who were to succeed them many millions of
years later - were both meat-eating and plant-eating. These were
The Age of Dinosaurs began in the Triassic period
(248-213 million years ago). The first-known dinosaurs, in the
late Middle Triassic period, evolved from a rabbit-sized creature.
By the end of this period, meat-eating dinos were as heavy as
From two legs to four
From the early predatory dinosaurs came plant-eaters
and from small bipedal (two-legged) herbivores there emerged four-legged
creatures as big as a bus.
In the Jurassic Period (213-144 million years ago
- the name comes from the Jura Mountain rocks of France and Switzerland),
new, enormous dinosaurs emerged. Herbivores were the prey of
megalosaurids, allosaurids and other huge sharp-fanged predators.
In the last, longest Age (144-65 million years ago),
toothless birdlike dinosaurs emerged. Tyrannosaurids, the heaviest
land predators, were ranged against new, powerful plant-eaters.
At the end of this Age, dinosaurs became extinct.
The sauropods were the largest animals ever known
on land. They were plant-eaters and they lived all over the world,
from about 185 to 64 million years ago. Their five-toed hands
and feet were made like elephants' feet and had a large, fleshy
Pillar-like arms and legs supported a body that was
bigger than several elephants put together. All of the sauropod
dinos had very long necks - they were a sort of prehistoric giraffe
- and equally long tails. Their heads were very small compared
with their bodies.
A life of non-stop guzzling
As plant-eaters, they probably spent much of their
time eating. The sauropods defended themselves against predators
by using their long, whiplash tails and large stamping feet.
Believe it or not
Inside the belly of a sauropod
Sauropods had spoon-shaped or peg-shaped teeth with
which they cropped leaves. They didn't chew but swallowed raked-in
food, which was passed to their stomach where it was digested
by "gastroliths" - gizzard stones which they deliberately
swallowed to break up their food. Its bulky digestive system
helped it to bear its own huge body weight on all fours.
Apatosaurus - "deceptive lizard"
to a group of sauropods that included Diplodocus,
Barosaurus and Mamenchisaurus. Apatosaurus
was 23 m (76 ft) long, 5 m (17 ft) high at its hips and weighed
41.3 tonnes (42 tons). For a long time scientists believed that
the sauropods were so big and heavy that they could only have
lived in water by using their nostrils like a snorkel. The water
would have helped to support their weight. But when Apatosaurus
footprints were found in rock in Texas, they changed their
minds. The huge footprint had not been made in mud deep under
water but in sand, damp enough to keep the print sharp.
Among the strangest dinosaurs, the hadrosaurs, or
duck-billed dinosaurs, were also some of the last alive on earth.
The "duck-bill" nickname comes from their wide, flat,
toothless beak, which had a horny cover and was used for biting
off twigs and leaves.
Would you wear an inflatable balloon on your head?
Strange though it was, this beak was quite ordinary
when compared with some of the head decorations of the duck-bills.
Tsintausaurus had a bony spike sticking up from
its skull and some hadrosaurs from North America had trumpet-like
crests of hollow bone. Saurolophus, from China
and North America, had an inflatable balloon of skin over the
top of the skull and some hadrosaurs like Edmontosaurus
from North America had inflatable areas of skin over the
These bony crests and blown-up balloons may have
been used to "talk" to each other. The inflated skin
and bony passages were connected to the nostrils and helped to
make loud calls.
I'd know that bony spike anywhere
It was also possible that the shape of bony spikes,
like the aerial of Tsintausaurus, would have been a visual
signal to other hadrosaurs.
An ancient, exclusive club
The duck-bills were plant-eating dinosaurs that usually
walked on broad-footed rear legs. They first appeared about 100
million years ago and lived in eastern Asia and western North
America, which were probably connected at the time. The hadrosaurs
were a very distinct group of dinosaurs, and were probably later
relatives of the group that included Iguanadon.
Biggest hadrosaur ever
Excavated in the Shandong province of eastern China
in 1964-8, and 15 m (50 ft) long, Shantungusaurus may
have been the largest of the hadrosaurs. This flat-headed giant
of the duck-billed world had large, strong, rear legs. Three
"hoofed" toes on each foot spread out to carry its weight.
Click here to find out more about Hadrosaurus
and the hadrosaurids (a group of hadrosaurs).
Ceratopsians were a group of ornithischian (bird-hipped),
herbivorous (plant-eating) dinosaurs with short, deep, parrot-like
beaks. These dinosaurs flourished during the Cretaceous period
(144-65 million years ago) and their sometimes alarming protective
features made them a worthy adversary of ferocious meat-eaters
such as T. rex. They were able to tackle tough plants with their
extra strong jaws, formidable beaks and scissor-like teeth. There
were three subgroups of ceratopsians: protoceratopsids,
ceratopsids and psittacosaurids.
Protoceratopsids: frightening or attractive?
as Protoceratops, Bagaceratops and Microceratops,
were relatively small, ranging from 76 cm (30 in) to 3 m (10 ft)
long. They had a bony frill around the neck that may have been
used to frighten predators, protect the neck, or attract mates;
the frill may also have served as an anchor for the jaw muscles.
Some species of protocerapsid also had brow ridges and small
horns on their noses and cheeks.
Ceratopsids: the big heads - not just frills but horns too
Ceratopsids, such as
Torosaurus ("Bull Lizard") and Triceratops
("Three-Horned Face") had neck frills that were
larger than protoceratopsids and horns on their brow and nose.
In some cases, ceratopsid brow horns were up 90 cm (3 ft) long.
These were the rhinoceroses of their time with huge heads (Torosaurus'
head, relative to its body, was larger than any other animal's),
bulky bodies and pillarlike limbs with hooflike claws. They probably
roamed in herds, browsing on low-growing vegetation. When threatened,
they charged their enemies.
Psittacosaurids: horns in the cheek
the only psittacosaurid known, was 2 m (6 ft 6 in) long.
In addition to the parrot-like ceratopsian beak, it had small
cheek horns (though it didn't have a bony neck frill) and its
eyes and nostrils were located high up in its head. It had long
hindlimbs and strong short forelimbs with blunt claws suitable
for walking on or grasping leaves. Its long tail counterbalanced
the fore part of its body when it walked or ran.
Prosauropods: small heads with leaf-shaped teeth
The first plant-eaters appeared in Late Triassic
time. They most likely evolved from some early predatory dinosaur
and the first large group of herbivores was the prosauropods.
These were saurischian (lizard-hipped) dinos that lived from
231-188 million years ago until Early Jurassic times and they
were distributed throughout the world.
Big ones and small ones
The prosauropods may have had the same ancestors
as sauropods (remember them? - the biggest land beasts ever!).
But the prosauropods varied greatly in size. Typical features
included a small head containing leaf-shaped teeth, a relatively
long neck and tail, and hind limbs that were longer than the forelimbs.
All known prosauropods had large, curved thumb-claws.
Lizard"): this was one of the smaller prosauropods, at about
2.1 m (7 ft) long and weighing 27 kg (60 lb). It had a small,
slim-snouted head with ridged teeth suitable for shredding leaves. It probably walked on all fours, but could have reared to feed.
Bigger than a tennis court?
Mountain Lizard") was one of the largest prosauropods at
about 12.2 m (40 ft) long - which is longer than a tennis court
is wide! A four-legged plant-eater with a small head and long
neck, it had a bulky body, elephantine legs and long tail.
Bigger and bigger
The small early bipedal (two-legged) prosauropods
probably gave rise to the huge, bulky quadrupedal (four-legged)
variety during the Triassic Period. By the end of Jurassic times,
the tendency towards increasing size reached its climax in colossal
sauropods. Their later decline was probably due to competition from the
ornithischians (bird-hipped dinos in the Late Triassic to Cretaceous period (220-65 million years ago) and the spread of plants that sauropods were badly equipped to eat.
Or maybe the prosauropods just got too big to move!
Heterodontosaurus ("Different Teeth Lizard")
This ornithischian was a small, fast plant-eater
1.2 m (3ft 11 in) long, with small, sharp cutting teeth, short,
curved tusks (maybe only in males), and close-packed, grinding
cheek teeth that chewed from side to side as well as up and down.
Life was no picnic for the prehistoric plant-eaters.
Eating a diet of plants causes animals many more problems than
eating meat. Plants are made of tough materials like cellulose
and woody lignin, and need to be broken down before digestion
can take place in the animal's stomach. Plant-eating dinosaurs
coped with their diet in a variety of ways.
Triceratops: powerful jaws and teeth
Dinosaurs like Triceratops ate tough,
fibrous plants. Triceratops, like many ceratopsians, had extremely powerful jaws and sharp
scissor-like teeth to help it to cope with its diet. After tearing
off the vegetation with its beak, it would then have sliced it
up with its teeth. The rough grooves and pits on the cropping
beak marked the place where the horny covering of keratin was
attached. The lower wider part of the bone (called the predentary)
fitted tightly against the lower jaw.
Sauropods: no chewing and not just of gum
The sauropods didn't chew at all, but simply swallowed
raked-in vegetation. This passed directly to the stomach, and
was ground up by deliberately swallowed "gizzard stones"
(gastroliths), or fermented by bacteria, as in a cow's stomach.
Sauropods' teeth were either spoon-shaped, for nipping, or peg-like,
for raking in leaves.
Hadrosaurs: chopped before swallowing
The hadrosaurs, or duck-billed dinosaurs, had special
teeth which ground and chopped their food before they swallowed
it. They could also store extra food in their cheeks, like hamsters.
Edmontosaurus (a duck-billed dino) had about 1000
strong teeth in its cheek region. It may have blown up the loose
skin on its flat face to make a loud bellowing call.
Ankylosaurs: small teeth - soft plants only
The ankylosaurs, or armoured dinosaurs, had small
teeth which were only good for eating soft plants. No dinosaur
had flat teeth like human molars, which we use to crush and grind
First plate-back dino
the first plate-back dinosaur ever found. A four-legged, plant-eating
vegetarian, Steggy is most easily recognised by its narrow snout,
short front legs and thin, spiny vertical plates jutting from
These triangular plates resembled armour and allowed
the animal to appear bigger and tougher than it really was. The
plates may have worked like solar panels, storing sunlight and
helping to regulate internal body temperature.
Sting in the tail
Stegosaurus' tail was
thick and heavy. At its base were four tall spines, arranged
in pairs and angled back towards the tip. These spikes were effective
weapons against predators like Allosaurus and Ceratosaurus.
One of the fascinating mysteries about Stegosaurus
is its very small brain compared to its large body size. Its
tiny brain was only about the size of a golf ball, weighing approximately
78 gm (2.5 oz).
Steggy's head was small too, only 40 cm (16 in) long,
narrow in shape, with a rounded beak like a turtle. Its thick
hind legs were long and powerful and its front legs were very
Stegosaurus' family ties - the "Roof Lizard"
Steggy belonged to the stegosaur family, a
group of ornithischian (bird-hipped) dinosaurs that lived from
Middle Jurassic to Late Cretaceous times (188-65 million years
ago) in what are now North America, Europe, Africa and Asia.
They were generally medium-sized dinosaurs, between 3 m (10 ft)
and 9.1 m (30 ft) long, with bulky bodies that weighed up to about
1.5 tonnes (1.47 tons).
There were two main subgroups of stegosaurs: stegosaurids,
such as Stegosaurus, Tuojiangosaurus, Kentrosaurus and
Wuerhosaurus, and huayangosaurids. Huayangosaurus,
the only known huayangosaurid, resembled stegosaurids but is thought
to be more primitive.
Biggest of the breed
Stegosaurus was certainly
the biggest stegosaur - in fact it was also the largest known
plated dinosaur - measuring up to 9 m (30 ft), which was three
times the average size of a stegosaur.
When did it live? And where?
Steggy thrived in the late Jurassic period (150 million
years ago) in what is now the United States. Remains have been found in Colorado, Oklahoma,
Utah and Wyoming. Though it became extinct before the end of
the Cretaceous period, this great beast walked the Earth for 50
million years. It was named in 1877 from an incomplete skeleton
Another brain in its hip?
Although Steggy had a tiny tubular skull with a brain
the size of a small golfball - or a big walnut - it is thought
that it may have had a second brain in its hip region.
More about those strange plates
Stegosaurus had small
flat plates on its neck and bigger diamond-shaped plates on its
back and the first part of its tail. These are usually shown
in two rows, but there may have only been a single row, or they
may have stuck out sideways like a protective shield over the
back. The exact function of these plates or spikes is not known.
They may have been for defence, for display, or for regulating
body temperature by absorbing or radiating heat.
Lizard") was one of the predators which may have fallen foul
of Steggy's spikes. This large flesh-eater - the most abundant
predator in Late Jurassic North America - was 11 m (36 ft) long
and weighed about 1.5 tons. It had a big head, S-shaped "bulldog"
neck and bulky body, balanced by a long, deep tail. The top of
its head had bony ridges and bumps, and its jaws held serrated,
the most advance dinosaur in a group known as bone-heads. This
dome-headed dinosaur's skull had a very thick and bony top, just
behind and above the eyes, covered with bumps and nodules at the
front and back of the neck. The density of the skull - 25 cm
(10 in) thick - was designed like a crash helmet to protect the
animal's brain during head-butting contests. Pachy had a short,
narrow face and ate only plants.
Head to head
Today male deer and goats batter each other head-on,
fighting for mates, and it is believed that this is just what
Pachy leaders did - defending their territory by charging and
butting heads like mountain goats.
The bony head spikes may have also been used to dig
up vegetation. Pachycephalosaurus ran on two legs with
its tail extended horizontally. It roamed the plains in herds
and may have moved into mountainous areas to avoid competition
Pachy's family ties
to the pachycephalosaurs, a relatively rare and puzzling
group of dinosaurs which lived towards the end of the Cretaceous
period, 65 million years ago. The first possible pachycephalosaur
remains that were discovered consisted of a single tooth from
the Judith River Beds of Montana in the late 19th century.
This was named Troödon formosus ("wounding tooth")
and over the next ten years similar teeth were discovered.
Mistaken for an armadillo
In 1920 a skull and partial skeleton were discovered
which were linked to Troödon, but it wasn't until
1940 that the almost complete, beautifully well-preserved skull
of another thick-headed dinosaur was discovered and the name Pachycephalosaurus
was finally given to it. In fact, when Pachy's bones were
first discovered in Montana they were misidentified as part of
the Tylosteus family, a giant armadillo-like reptile!
High domes and low domes
Pachycephalosaurs have been divided into high-domed
forms (pachycephalosaurid, such as Pachy and Stegoceras);
and low-domed forms (homalocephalid, such as Homalocephale).
Remains have also been found in Madagascar, China and Mongolia.
How big was Pachy?
As the largest of the bone-heads, Pachy was 4.6 m
(15 ft) long. His name means "Thick-Headed Lizard".
How did that compare with other bone-heads?
Roof") was much smaller - a mere 2.5 m (6 ft 6 in).
Were all bone-heads the same?
No. The difference between pachycephalosaurids and
homalocephalids, which were the two kinds of pachycephalosaurs,
probably reflected their different behaviour patterns.
Head-butters vs head pushers
Whereas Pachy and Stegoceras belonged to the
pachycephalosaurids who had high domed heads and the males practised
head-butting, Homalocephale (the name means "Even
Head") belonged to the sub-order of homalocephalids which
were flat-headed bone-heads. They had a large, flat, fairly smooth
skull roof with nodes along the back. Rival males probably pushed
against each other like bighorn sheep. The homalocephalids may
not have been a single family but a sequence of increasingly advanced
All pachycephalosaurids such as Pachycephalosaurus
walked with level back and were not designed for running fast.
They ate leaves, fruits, seeds and perhaps insects. They would
detect danger with sharp eyes and a keen sense of smell. The
winners of the males' head-butting contests mated with and ruled
the herds of females.
What do their teeth have to tell us?
The first specimens of pachycephalosaurs were their
teeth. Their compressed, slightly curved and serrated nature
suggests that they belonged to a herbivorous (plant-eating) animal
and that they were used to shred plants. In many ways, Pachy's
lifestyle was something like that of modern sheep and goats:
they probably lived in small groups in upland areas.
Undoubtedly Pachy's head-down charging was also used to fend off enemies, as well as in fighting for dominance within its own group. A typical adversary would have been Abertosaurus, a Late Cretaceous saurischian - like a smaller version of T. rex.
was one of the most distinctive of all the crested dinosaurs.
This crest was a long, curved, hornlike tube that arced back
from its head towards its shoulders. This amazing bone structure
was double the length of the dinosaur's head. Its elaborate crest
was filled by hollow air passages which may have emitted low-frequency
sounds, that could have been useful in communicating with other
dinosaurs. Parasaurolophus was huge, weighing over 2 tons,
but highly adaptable. It could walk upright or move about on
All beak and teeth
This dinosaur probably ate tough tree material like
pine needles and oak leaves. Like all hadrosaurs, it had a duck-like
beak. Behind the beak were several rows of teeth, used for crushing
and grinding. It had the ability to replace old teeth as they
became worn out. Because the beak was scoop-shaped, scientists
believe Parasaurolophus also ate plants from shallow water
Parasaurolophus had keenly
developed senses, with remarkable vision and acute hearing. While
browsing in herds, its well-developed senses kept it alert to
approaching danger. It had strong, muscular legs and toed hooves.
Its front legs were short with webbed fingers. It could run
and was probably also able to swim.
Parasaurolophus was a
hadrosaur - a group of ornithischian (bird-hipped) dinosaurs
that lived during Late Cretaceous times (97.5-65 million years
ago). All hadrosaurs had duck-billed beaks, and although these
were toothless, they had large numbers of cheek teeth - sometimes
more than 300 in each jaw.
Flat skulls vs bony crests
There were two main subgroups of hadrosaurs: hadrosaurids
(such as Gryposaurus and Maiasaura)
and lambeosaurids (such as Corythosaurus and
Parasaurolophus itself). The main difference between
the subgroups was the shape of the skull: hadrosaurids had flat
skulls, some with bumps of solid bone on the snout, whereas the
skulls of lambeosaurids had large, hollow, bony crests.
How long? Parasaurolophus
was 10 m (33 ft) long. From its head
a 1.5 m (5 ft) curved hollow tube (the crest) projected back above
Evidence: Remains have
been found in Alberta, New Mexico and Utah.
length was about the same as that of another lambeosaurid, Corythosaurus;
one striking difference between these two crested hadrosaurs was
in the crest itself: whereas Parasaurolophus' was tube-shaped,
Corythosaurus' was shaped like a large dinner plate set
up on end on top of the skull.
Another unusual crested hadrosaur was Tsintaosaurus
whose crest pointed forward. It took the form of a hollow tube
that pointed straight up between the eyes.
Teeth, teeth and yet more teeth
Incredible as it may seem, Parasaurolophus
may have grown up to ten thousand teeth in its liftetime!
There have been a number of theories about the function
of Parasaurolophus' extraordinary crest.
Underwater snorkel: it allowed Parasaurolophus' to breathe underwater while feeding on submerged plants. (Drawback: there was no actual hole at the tip of the crest through which air could have passed!)
Air storage tank: it helped Parasaurolophus' to stay submerged for long periods while feeding. (Drawback: the amount of air that could have been stored was very small!)
Salt glands: it housed salt glands to regulate salt balance in Parasaurolophus' body.
Smelling device: it was an advanced smell detector.
Signalling device: the crests of individual species of hadrosaurids helped them to signal to members of their own species - especially useful for courtship and mating!
Foliage deflector: perhaps
Parasaurolophus lived in quite heavily wooded areas, using
its crest as a deflector to crash through heavy foliage to escape
their predators without damaging their heads. And just as the
elaborate crests of lambeosaurids like Parasaurolophus indicate
that they lived in dense forests, did flat-headed hadrosaurids
live in open areas where deflectors were not necessary?
The massive Triceratops ("Three Horned
Face") is the most well-known of the horned dinosaurs. It
was the largest, measuring up to 9 m (30 ft) long, heaviest and
most visually distinctive. Named for the three horns on its nose
and brow, it had an extremely elaborate head frill, like a huge,
open fan. Some Triceratops' horns measured 100 cm (40
in), about the length of a golf club.
Triceratops had a large
brain and sharp vision. Scientists believe it could run fairly
well for its large size. With its stout stature and massive head,
it resembled a larger, modern-day rhinoceros. Triceratops
weighed approximately 5 tonnes (5.5 tons) and required a lot of
plant material to sustain its enormous bulk. Its teeth were like
long blades, operated like shears, but functionally unable to
crush or grind. This great dinosaaur ate palm leaves and may
have knocked over tall trees to get to the top, tender branches.
The best form of defence
Though Tricer had an aggressive nature, it had no
lasting enemies because it could outmanoeuvre opponents with its
facial horns, a strategically well-designed defence mechanism.
("Terrible Three-Horned Face")
belonged to the ceratopsid subgroup of the ceratopsians
(horned dinosaurs, see pages 8-9) and was among the last-known
dinosaurs on the planet. Ceratopsians seem to have grown bigger
and bigger as they evolved. An early ceratopsian Protoceratops
("First Horned Face") was not much bigger than
a large dog. What they had in common was the large bony neck
frill pointing backwards from the skull and masking the neck,
horns on the nose or over the eyes, and a narrow hooked beak.
Most were four-legged and stocky, like today's rhinoceroses,
and all were plant-eaters.
Many fossils of ceratopsians found in the same area
suggest that they roamed in herds, confronting a threatening meat-eater
as a pack.
Remains of Triceratops have been found in
Colorado, Montana, Wyoming and Canada.
Tyrannosaurus meets Triceratops
Sometimes, even the mighty T. rex can meet its match.
Triceratops is well-protected against the
fierce predators, such as Tyrannosaurus, that track the
herds of plant-eaters across the great plain. Triceratops'
giant, bony frill also makes its head look huge and frightening
to deter any prowling carnivore or meat-eater. Triceratops
has long, sharp horns on its forehead and snout. In addition,
the dinosaur has specially strengthened bones on its neck and
hip area and on the roof of its skull to withstand great shocks if it charges into an attacker.
The monster attacks
A hungry T. rex spots a Triceratops, feeding
away from its herd. The meat-eater rushes at its prey, hoping
to knock it down. It will try to wound Triceratops with
one fatal bite from its dagger-like teeth. Tricer shakes its
head, bellows, and lunges towards its attacker
As Triceratops rises from the ground, its
long back legs push its hips upwards. Huge muscles support Tricer's
great 6-tonne (6 ton) body over its front and rear legs. Its
hip bones take the strain of its heavy body weight. Breaking
into a run, perhaps as fast as 25 km/h (over 15 mph), it charges
forward, trying to stab Tyrannosaurus' belly with its horns.
If it succeeds, Triceratops may escape from death - this time.
Standing its ground
Tricer may look a little like a rhinoceros - but
it's twice the size and a reptile, not a mammal, though it may
have had similar ways of defending itself. Pawing the ground,
its legs kicking up a cloud of dust to confuse its attacker, it
hisses at T. rex, looking for a way to escape the terrible hunter's
razor-sharp, slashing teeth. But Tyrannosaurus is growing
tired and may decide to give up and hunt a weaker animal.
a neck three times the size of a giraffe. It belonged to a group
called the sauropods and had a tiny head compared to its long
neck and tail. Its body was perfectly designed for its lifestyle,
allowing it to feed from the tops of the tallest trees. It munched
on leafy vegetation few other dinosaurs could reach.
Hoovering up, Jurassic style
Its neck was strong and flexible, capable of raising
and lowering with ease. Built like a modern-day crane, its head
was lightweight and compact, allowing freedom of movement and
quick manoeuvring in close quarters. It may have eaten the plants
from shallow lakes, swinging its neck along the sides like a powerful
vacuum hose. Its body was designed to support its enormous weight.
Backbones were strong and hollowed out for lightness. Its muscular
legs supported its body structurally like the architectural pillars
and when the vegetation was gone, it moved on to the next lake.
to the euhelopodid family ("Good Marsh Feet") of sauropods.
They lived in the Late Jurassic Age (95-60 million years ago).
These large four-legged plant-eaters have only been found in
China, and are sometimes grouped with the camarasaurids. Like
those, euhelopodids had chisel-shaped (or spoon-shape) teeth and
a tall blunt snout. Like Mamenchisaurus, many euhelopodids
had amazingly long necks with 17 vertebrae.
Highest number: In fact,
Mamenchisaurus had 19 neck vertebrae, more than
any other known dinosaur. Many of these vertebrae overlapped
with long, thin, reinforcing bony struts.
Evidence: Remains have
been found in Sichuan, Gansu and Xingjiang, China.
was possibly 27 m (89 ft) long - yes,
89 feet! - with the world's longest known neck perhaps measuring
up to 15 m (49 ft). As Winston Churchill said, "Some neck."
Marsh Feet"): half its length, a mere 10-15 m (33-50ft),
weighing up to 25 tons. Other euhelopodids: Omeisaurus,
20 m (66 ft) ; and Tienshanosauraus, 12 m (40 ft)
Diplodocus - long neck, long tail
Another massive long-necked sauropod was Diplodocus
(26 m, 86 ft) long whose neck, unlike Mamenchisaurus,
was balanced by a long tail.
Mimic") was the largest of the birdlike dinosaurs. With
its toothless beak and long tail, it resembled a modern-day ostrich.
It had large eyes, a small head with a narrow beak, long, slender
S-shaped neck and powerful long, slim hind limbs. Its thin front
"arms" had elbow joints that bent for flexible movement.
The structure of its internal anatomy was similar to a bird's.
Scratching and scraping
Gallimimus had non-grasping
clawed "hands" that could not have torn meat. It may
have scratched and scraped the soil and eaten the eggs of other
animals. Its body was covered with scaly skin and its feet were
clawed, front and back. Its long tail extended over the ground.
When it ran, its tail was stiff, held horizontally for balance.
One of the fastest
Gally was one of the fastest of all the birdlike
runners, with speeds up to 40 km/h (25 mph).
Remains have been found in Southern Mongolia.
Gallimimus lived in Late
Cretaceous times (95-65 million years ago) and belonged to the
ornithomimosauria group of the ornithomimidae ("bird
mimics") family. The ornithomimidae were saurischians ("lizard-hipped
dinosaurs") and all looked like ostriches with small, light
head, relatively big brain, large eyes and long narrow beak.
They had long, slim, curved, mobile necks, compact bodies and
fairly long arms with grasping, clawed, three-fingered hands.
They had long, strong legs, with longer shins than
thighs and long feet, each with three toes tipped with claws.
The stiffly held tapered tail positioned level with the back
balanced the forepart of the body when they ran. Ornithomimids
ate low-growing plants, eggs and maybe insects and small reptiles.
They might have kicked enemies but their chief defence was a
Biggest of the breed
Measuring up to 6 m (20 ft) long, Gallimimus was
the biggest in its family.
How did Gallie compare with other ornithomimids?
("Emu Mimic"): half the size of Gallie but half again
as fast; it was 3.5 m (11 ft) long and weighed 100 kg (230 lb),
with big, keen eyes, toothless beak, long neck and tail, short
back, slim arms with three-fingered hands, and long legs capable
of running up to 64.4 km/h (40 mph), compared with Gallie's 40
km/h (25 mph) speeds.
Lizard"): reputedly an ancestral ostrich dino 3.5 m (11 ft
6 in) long, with light, hollow bones, but, compared with later
ornithomimids, shorter arms and legs and a shorter running speed.
Mimic"): 3.5 m (11 ft 6 in) long, with small head, toothless
beak, long curved neck, thinner arms than Struthiomimus,
three clawed fingers on each hand, long sprinter's legs and long
tail occupying more than half its length.
Mimic"): ostrich-like predator (or herbivore) 3.5 m (11 ft
6 in) long, with fairly strong arms.
What big eyes you've got, Gallie
Galliminus' eyes were
bigger than ostriches, yet its skull was narrower. Its eyeballs
were actually flattened and could not move much in its socket.
This means that Gallie and all the other ostrich-mimics (ornithomimids)
must have had to flick their heads to and fro to sight in on various
Look out it's behind you!
Because Gallie's eyes faced sideways, its binocular
vision (ability to use both eyes together at the same time which
enhances vision) was more limited than in some other protobirds
(early bird-like dinosaurs). However, to compensate for this,
it was better adapted to detect predators from behind.
Advantages of a full belly
ribs show that the belly's lower contour is not as hollow as in
hungry predator theropods (meat-eaters). This is because ostrich
dinos always kept their bellies at least partly filled with digesting
plant material in order to support the flora of micro-organisms
that do the actual breaking down of plant materials.
was a member of the hadrosaurids (a type of hadrosaur). Confused?
Then see Family ties for an explanation!
Prehistoric waste disposal
a duck-billed dinosaur that lived during the Late Cretaceous era.
Though its beak was toothless, Hadrosaurus had up to 300
cheek teeth in each powerful jaw. It could grind tough vegetation
like a waste disposal unit. Which was fortunate because Hadrosaurus
was a browser, which grazed continuously.
Haddie's body was heavy with a long head that ended
in a flat, horny bill. It resembled a large, oddly shaped kangaroo,
standing on its hind legs, with shorter front legs dangling in
front. Its toothless beak indicates that this dinosaur was primarily
a land feeder, dining on palm fronds and needles.
First mounted dino
Hadrosaurus was the first
mounted dinosaur skeleton ever displayed - at Philadelphia in
Hadrosaurus was a member
of the hadrosaurids (a type of hadrosaur). That might sound like:
"A human being is the member of the human race (a type of
human)", but actually it's rather different. What it means
is that Hadrosaurus was a species of hadrosaurid,
which was a particular subgroup of the larger group of hadrosaurs,
which were duck-billed dinosaurs. (Click here to find out more
So what on earth were hadrosaurids?
Hadrosaurids ("big lizards") were a family
of medium to huge, heavily built bipedal (two-footed) or quadrupedal
(four-footed) plant-eaters; they were among the last and largest
of all bird-footed, bird-hipped dinosaurs. There were two such
families of hadrosaurs or duck-bills, so nicknamed because of
their broad, flat, toothless beaks. Both groups had powerful
jaws and pavements of self-sharpening cheek teeth chewing leaves
and twigs stored in roomy cheeks. Most were big and heavy, with
longer limbs and deeper tails than their forebears. Each hand
had only four fingers, cushioned in a padded paw.
The difference between hadrosaurids and hadrosaurs
Unlike other hadrosaurs, hadrosaurids had a flat
skull or one with crests or bumps of solid, and a relatively longer
lower jaw and longer, slimmer limbs.
Hadrosaurus: some facts and figures
Haddie was 8-10 m (26-32 ft) long; its mode of attack
was head-butting. Remains have been found at Alberta in Canada;
and New Jersey, Montana and New Mexico in the USA.
How did Hadrosaurus compare with other hadrosaurids?
Aralosaurus ("Aral Lizard"): early hadrosaurid, known from an incomplete skull with a Hadrosaurus-like low bulge in front of the eyes.
Brachylophosaurus ("Short-Crested Lizard"): this primitive hadrosaurid was about 7 m (23 ft) long, with long forelimbs, deep snout, low nasal crest and (between the eyes) a bony plate forming a short, backward-pointing spike.
Lizard"): a small, early hadrosaurid 3.7 m (12 ft) long with
long hind limbs, slender feet and body, and rows, not batteries,
of teeth behind the toothless beak.
More of Haddie's relatives
Lizard"): large, flat-headed hadrosaurid, bigger than Hadrosaurus,
being 13 m (42 ft 6 in) long and weighing nearly 3.2 tonnes (3.5
Mother Lizard") : this bipedal (two-legged)/quadrupedal (four-legged)
plant-eater was about 9 m (30 ft) long, with short, broad, toothless
beak, batteries of cheek teeth in shallow jaws, and a short bony
crest between the eyes. It was found near nests that were 2 m
(7 ft) across, containing the fossil young of different ages.
Bumps and bellows
Hadrosaurus walked on
all fours but stood on hind legs, balancing its body with the
aid of its long, stiff tail. Its skin was tough and leathery
and its skull was flat, often with bumps on the snout. Scientists
believe that it had a very loud voice.
Hadrosaur bones - they're all over the place
Hadrosaur fossils make up about 75% of all land animal
bones that have been found.
Palaeontology: looking for clues
Palaeontology is the study of the geological past.
Scientists have made maps to show the different ages of rocks.
Dino fossils are found throughout the world in 210-64 million-year-old
How are fossils made?
When most animals die, their remains are broken up
and destroyed by the weather and by other animals. Sometimes,
however, their bodies are washed into a river or lake and quickly
covered in sand and mud; in a desert the remains might be covered
by wind-blown sands. This is how some dinosaurs became preserved.
Permineralization - minerals reinforced the bones
Over millions of years more and more sand and mud
piled on top of the remains. The sediments gradually turned into
sandstone, limestone and shale, the soft parts of the dinosaurs'
scaly skin lasted long enough to leave its impression in the fine
mud, and fragile egg shells were also turned into fossils.
Petrification - turned to stone
The fossils discovered by scientists are different
from the dinosaurs' original remains. Chemicals have changed
them into stone, or they may have been crushed. Sometimes minerals
replaced the bone itself until the bone was turned to stone.
Different types of remains
Teeth: the hardest parts
of all, often surviving with little change at all; the fossilized
teeth of plant-eating dinosaurs are blunt and flat
Moulds: certain minerals
dissolved some bones but left bone-shaped hollow fossils called
Casts: a mould that was
later filled by other minerals became a cast; some moulds or casts
even show a dinosaur's scaly skin
Trace fossils: other traces
left by dinosaurs, including:
Ichnites: fossil footprints,
left in lakeside mud that dried out in the sun; fossil trackways
show where dinos walked on two or four limbs, whether they trudged
or sprinted, and travelled singly or in herds. Click here for more information
Coprolites: these fossil
droppings are moulds showing the shape of the intestines
Ooliths: fossil eggs
What fossil tracks tell us
Fossil tracks reveal that dinosaurs stood, walked
and ran with limbs beneath bodies. They also show where, when
and how sauropods, hadrosaurs and others moved and rested on the
muddy sides of lakes.
Herds of herbivores
Big herbivores (plant-eaters) such as sauropods walked in herds. Washtub-sized depressions left
by huge feet in mud and now hardened into rock show where sauropods
once roamed. Finds from Texas and other places suggest sauropods
and other herbivores trudged in herds, perhaps in seasonal migration.
Tracks of the theropods
Theropods were meat-eaters, and large and small predatory
dinosaurs left birdlike tracks on the muddy shores of lakes and
rivers in the Connecticut valley and elsewhere. Some were probably
scavenging corpses washed ashore; others ambushed herbivores that
had come to drink.
Tracks other than footprints indicate where a dinosaur
sat down to rest or doze.
Running dinosaurs left footprints far apart - the faster they ran, the greater the gaps.
One set of tracks indicates that large theropods (meat-eating
predators) could run at 40 km/h (25 mph). Small prints usually
mean they were small animals. An Early Jurassic trackway in Arizona
revealed that a theropod no heavier than a whippet had sprinted
as quickly as a galloping horse.
Swimming dinos: fossil
tracks with incomplete footprints suggested that dinos sometimes
swam. A hindfoot print marked where a big herbivore kicked off
to change direction, the limb functioning as a kind of punter's
pole to push off from a lake bed.
Walking dinos: tracks
with short distances between footprints indicate slow speeds.
Traces left by sauropods suggest they always ambled and never
Tails raised: where tracks
show no groove left by a dragging tail, it has been deduced that
the tail was held aloft to balance the body and prevent the tail's
being trodden on by other members of the herd.
The tools of the trade
Dinosaur discoveries are rare, often lying buried
in layers of rock until exposed on a hillside, a quarry or perhaps
a rocky beach. Only then can a team of experts go to work to
excavate fossil dinosaur. They use pick-axes and shovels
to clear away rock; hammers and sharp chisels to work close to
the bone without damaging it, and brushes to sweep away the dust.
Workers wear protective goggles to keep their eyes safe. Hard-hats
are essential near cliffs.
Protecting the fossils
Wet tissue paper is spread over the fossil to protect
the surface. Thick bandages or sacking are soaked in plaster
and spread over the paper. When this has hardened the fossil
is carefully turned over. Its other side is also covered in paper
and plaster bandage. When the plaster has hardened, the fossil,
wearing its "jacket", can then be lifted out.
Putting dinos together again
After the hard work of excavation, the precious fossils are taken back to the laboratory for preparation, study and display. They are removed from their protective jackets; then the remaining rock or earth is cleaned away with chisels, delicate power-driven tools and chemicals. The cleaned
bones are then studied to understand how they fitted
together - and therefore how the dinosaur lived. Tell-tale clues
can be found on the bone surface: muscles sometimes leave clear
marks where they were attached.
Adding the flesh
It may take some time to work out how the bones fitted
together and missing bones may have to be modelled from plaster.
Skin impressions have sometimes been preserved to aid the model-maker,
but colour is a matter of guesswork.
A load of old bones
During the 19th century, when dinosaurs
had just been discovered, the sculptor Benjamin Waterhouse Hawkins
built models of dinosaurs first in Britain, then in America.
The remains of herbivore (plant-eating) dinosaurs
have been found all over Europe, but the fossilized skeletons
tend to be less complete than elsewhere. Among those discovered
are: Plateosaurus ("Flat Lizard"), 6-8
m (20-26 ft); Iguanodon ("Iguana Tooth"),
9 m (30 ft); and Scelidosaurus ("Limb Lizard"),
4 m (13 ft).
This part of the world has been popular with dinosaur
hunters since the mid-19th century. Famous plant-eating
finds include: Camarasaurus ("Chambered Lizard"),
18 m (59 ft); Parasaurolophus, 10 m (33 ft); Triceratops
(see pages 26-9), Euoplocephalus
("Well-Armoured Head"), 7 m (23 ft); Stegosaurus
(see pages 14-17) and Apatosaurus
("Deceptive Lizard"), 21 m (69 ft). New dinosaur
remains are still being discovered here.
Much of South America is covered with dense vegetation,
making it difficult to dig for dinosaur remains. But important
finds have been made in the more barren areas further south.
Plant-eating finds include: Mussaurus ("Mouse
Lizard"), 3 m (10 ft); Amargasaurus, 9 m (30
ft); and Riojasaurus, 10 m (33 ft).
This huge continent has been home to many different
kinds of dinosaurs. The oldest are found in the south; younger
dino remains are further north. Among important finds: Massospondylus
("Massive Vertebrae"), a two-legged/four-legged
plant-eater 4 m (13 ft) long, with long neck and tail, bulky body,
massive hands, rounded front teeth, flat-sided back teeth, and
possibly a horny lower beak.
Some of the most recent and exciting finds have been made in Asia, including Yingshanosaurus, 5 m (16 ft); Tuojiangosaurus, 7 m (23 ft); Saurolophus ("Ridged Lizard"); 9 m (30 ft); and Shantungosaurus, 15 m (49 ft). Fossilized dino bones (once thought to belong to dragons!) are found all over China. Many dinosaur remains, including dino eggs, have been discovered in the Gobi Desert.
Not many dino fossils have been found: the most complete
dinosaur discovered here was the plant-eating Muttaburrasaurus,
7 m (23 ft).
Only two dinosaurs have been excavated here so far,
in 1988 and 1889, but there may well be many dino fossils under Antarctica's icy waters.
Before people understood how old the Earth was, they
entertained ideas about fossils that now seem very funny: they
were put there by the devil to confuse people; or they were the
remains of animals drowned in the Flood when Noah escaped in his
ark. The explanation nearest to the truth was the suggestion
that fossils were mistakes that God made while creating all the
and theories of extinction
About 65 million years ago dinosaurs, plesiosaurs, pterosaurs and many other animals of land or sea became extinct. Just why remains a mystery that many scientists have tried to solve. Among the theories: dinos evolved such awkward bodies that they couldn't move or breed; predatory dinos ate the rest then starved; tiny mammals gobbled up dino eggs. But the most likely explanations have been drastic global change or relatively slow extinction as shifting continents, rising mountains and shrinking seas helped new creatures evolve who outcompeted the old.