"Terrible meat-eating lizards"

They roamed the Earth from about 240 to 65 million years ago. 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". And some of them had deadly, slashing teeth and claws which they used to kill, and eat other reptiles.

These were the carnivores and they loved their meat …

What's for dinner - meat, veg … or both?

Carnivores were predators, hunting, killing and devouring other weaker or smaller animals, including other dinosaurs, but particularly their prey became the more gentle, peaceful herbivores, or plant-eaters. 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 omnivores.

Triassic Dino

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 arabbit-sized creature. By the end of this period, meat-eating dinos were as heavy as cows.

From two legs to four

From the early predatory dinosaurs came plant-eaters and from small bipedal (two-legged) herbivores emerged four-legged creatures as big as a bus.

Jurassic Dino

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.

Cretaceous Dino

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.

"Beast feet"

All meat-eating dinosaurs were theropods - literally "beast feet". Theropods existed from the Upper Triassic to the Upper Cretaceous Ages (190-65 million years ago). Some dinosaurs who were theropods belonged to a group called carnosaurs.

What Carnies were like

Carnosaurs - or Carnosauria - were large, flesh-eating, saurischian (lizard-hipped) dinos, ranging in length from 6.1 m (20 ft) to 15.2 m (50 ft) and weighing up to about 6.4 tonnes. Another way of putting it is: they were very, very big. They were also very successful as a group - you could say they were a kind of Prehistoric Jet Set - and their fossils have been discovered throughout the world.

So what did they look like?

Typical carnosaurs, such as Tyrannosaurus and Allosaurus, had large heads, short muscular necks, powerful hind legs (they were bipedal, meaning they walked on two of their "beast feet") and stiff, heavy tails to aid balance.

Meat-eaters who swallowed vegetarians?

All in all, carnies were the most formidable of all predatory dinosaurs. And they particularly hunted herbivores (plant-eaters). The carnosaurs possessed the kind of jaws that could have swallowed a human whole, and they had lots and lots of curved, serrated teeth up to 18 cm (7 in) long for ripping flesh from their prey.

The huge "sailing" Spinosaurus

Some carnosaurs had unusual features; for example, Spinosaurus - at 15.2 m (50 ft) the largest carnosaur yet discovered - had a 1.5 m (5 ft) tall "sail" along its back. The exact function of this sail is not known. It may have been used to regulate body temperature, attract mates, or frighten other dinosaurs during territorial battles.

Fishy Baryonyx

Another unusual carnosaur was Baryonyx, whose long neck, crocodile-like jaws with many sharp teeth, and relatively long forelimbs with large hooked claws were probably adapted for hunting fish.

The brainiest of the breed

Theropods were the brainiest of all dinosaurs and the brainiest group of all theropods was the coelurosaurs. In contrast with carnosaurs, they were small, slightly built, nimble and fast-running predators with small heads - whose narrow jaws were lined with small, sharp teeth - long flexible necks and long arms with sharply-taloned grasping hands.

"Hollow lizards"

Coelurosaur means "hollow lizard" and they were probably the most successful of the lizard-hipped dinos. Some coelurosaurs were the fiercest of predators, including a species considered to be the ancestor of the first true bird.

Fossil famine

Unfortunately, although coelurosaurs must have been quite abundant throughout the 140 million year reign of the dinosaurs, the fact that they were both small and slender has reduced their fossil evidence. Small animal carcasses tend to rot quickly and their skeletal remains are liable to be scavenged and scattered, or completely destroyed.

An odd mixture

The coelurosaurs were an odd mixture of small, nifty theropods, who may not have been close relatives but shared physical characteristics. They were all fast runners, hunting for mammals and insects. Coelurosaurs were the "clean-up squad", finishing off food after carnosaurs had had their fill.

"Bird robber"

One of the most active predators of the coelurosaur clan was Ornitholestes ("bird robber"). About 2 m (6.5 ft) long, Orni fed on small animals like lizards, frogs and early mammals. It had strong jaws and powerful grasping hands. and may have captured early birds for food.

"Hollow form"

Among the earliest coelurosaurs was Coelophysis ("Hollow Form"), another small, agile dinosaur 1 m (3 ft) tall, with a wedge-shaped head and sharp, serrated teeth, who chased after its prey, grabbing small lizards in hands set free by its upright posture. Fossils reveal that the species' prey may have included its own babies!

When did they arrive?

Dinosaurs first appeared 230 million years ago, at the beginning of the Late Triassic Age. The earliest-known were the carnivorous (flesh-eating) herrerasaurids and staurikosaurids, such as Herrerasaurus and Staurikosaurus.

"Herrera lizard"

Too primitive to be saurischian (lizard-hipped) or ornithischian (bird-hipped), Herrerasaurus was a two-legged flesh-eater 3 m (10 ft) long, with sharp teeth, short, birdlike, folding arms, longer thighs than shins, four-toed feet and hip bones with saurischian and ornithischian features. Fossils have been found in northwest Argentina. Herrerasuria may have been the stock that gave rise to all other dinosaurs.

"Southern Cross lizard"

Staurikosaurus was another primitive dinosaur, a speedy, lightly built two-legged carnivore 2 m (6 ft 6 in) long and weighing 30 kg (66 lb), with a large head, sharp teeth, short arms, long legs and tail, five toes and fingers, and only two vertebrae joining spine to hips.

What was their prey?

Life on Earth was originally water-based until amphibians living on land and in water ("amphibious" means "having a double life") evolved from meat-eating fishes. Only after reptiles conquered the land did vertebrates begin eating plants.

And meat-eating dinosaurs were there already, waiting for them!

Reptile eats reptile

In the Triassic Age, many sprawling reptiles and amphibians were killed off by thecodonts, reptiles of the archosaur group. Thecodonts died out, many killed by the earliest dinosaurs such as herresaurids and staurikosaurids.

Dinosaur eats dinosaur

Small predators chased lizards, seizing them in sharp-clawed hands, swallowing them head first. Others roamed in packs, creeping up on big plant-eaters then killing them with a sudden rush. Dinos ate each other, theropods striking with their fangs and sharp toe and finger claws. The toothless variety made do with

insects or digging up and eating other dinosaurs' eggs.

So what was so special about T.rex?

Tyrannosaurus was the biggest and strongest meat-eating animal ever - nearly as tall as a double-storey house. Although it was very heavy, scientists believe it could sprint over short distances to catch slow-moving dinosaurs.

Family ties of the "tyrant lizard"

Tyrannosaurus rex ("tyrant lizard") belonged to the Tyrannosaurids, a closely knit group of Late Cretaceous (65 million years ago) theropods. Its closest relatives were Daspletosaurus and Tarbosaurus, both very similar types. One further relative is Albertosaurus - though separated slightly from its cousins because of its light build.

When it lived and where

Remains have been found in Late Cretaceous rocks in Colorado, Montana, New Mexico, South Dakota, Wyoming, China and Mongolia. It lived for a comparatively short period - in dino terms - 70-64 million years ago. But in that mere 6 million years tyrannosaurids established themselves as the main predators. Indeed T. rex is one of the last known dinosaurs.

How big was big?

With a length of 14 m (46 ft) and a height of 5.6 m (18.5 ft), T. Rex was one and a half times as big as its closest relative, Daspletosaurus, whose length was 9 m (29.5 ft). Weighing 5 tons it could run at a speed of 15 to 25 mph and had a life span of up to 200 years.

Terrible teeth

T. rex had a massive skull with powerful jaws that held serrated 18 cm (7 in) long teeth which could be compared in length and shape to a set of steak knives. The tyrannosaurids were not recognised as a distinct group until 1906, shortly after the first reasonably complete skeleton of Tyrannosaurus was discovered in Montana in 1902. But 50 years earlier in the mid-nineteenth century. Joseph Leidy, the pioneering palaeontologist, described the set of teeth also collected in Montana, and later identified as belonging to T. rex, as Deinodon horridus - "horrifying, terrible tooth".

Big-headed beast

With its enormous head and barrel-shaped body, T. rex is the most widely recognized of the ancient predators. It walked upright on long, powerful hind legs with three-taloned feet. Its small forearms had tiny, two-clawed hands. Standing it would have been tall enough to peek into a second-storey window.

Tail up or down?

For many years after its discovery, Tyrannosaurus rex was incorrectly displayed as having its long tail dragging on the ground. It is now thought that the correct position is more likely to be: tail out, balanced in the air.

"Dem bones, dem bones, dem dry bones"

Because of its massive size (14 m (46 ft) long) and weight (7 tons) , Tyrannosaurus' skeleton is an amazing balance between the need to bear this massive weight and to run around to catch food. Its massive skull, built to withstand impact, is supported by a stout neck. The backbones acted like a massive girder

With these hands …

The arms and hands of Tyrannosaurus are among its most bizarre features. The forelimbs of carnosaurs tend to be relatively short when compared with those of the more lightly built coelurosaurs. In T. rex and tyrannosaurids generally this trend seems to be taken to a ridiculous extreme. The shoulderbone is moderately large, but the arm is minute and ends in a small two-clawed hand.

What was the claw for?

There are various theories about T. rex's two-clawed hand. One suggestion is that the hand might have been used as a kind of grappling hook during mating, or to anchor the front of the body as the animal tried to raise itself after resting on the ground.

Footloose and fancy free

T. rex's feet are much stronger than its hands since the back legs take the animal's weight. The broad short feet have three forward-pointing toes ending in sharp, curved claws.

Born to kill

T. rex was a ferocious hunter, able to charge with great speed. Following and ambushing herds of plant-eaters, it was able to judge distances when attacking its prey with the help of its forward-facing eyes. Probably using its tiny arms to push itself upright after it had been lying down, swinging its muscular tail, it moved in for the kill, lunging forward, massive jaws open, throwing its head up and roaring.

Just one bite

T. rex could kill with one crushing bite of its massive steak-knife teeth, twisting its powerful neck, ripping flesh from its prey, pinning the carcass to the ground with its large birdlike feet. With its huge appetite, it could have easily eaten its own weight in meat every week and probably stole the kills of other animals to survive. Tyrannosaurus' skeleton shows broken bones, leading experts to believe that it engaged in a lot of fights.

The laid-back lifestyle of Albertosaurus

Unlike its tyrannosaurid relative T. rex, Albertosaurus was a very slow-moving creature of sluggish habits, who would lie prone on the ground for long periods. When driven by hunger, Albertosaurus would raise itself to its feet and slowly pace about in search of food, relying mainly upon scavenging the carcasses of dead animals.

T, rex: quick mover - but short distances only

In contrast with its lazy cousin, Tyrannosaurus was a dynamic animal. In spite of its great weight, it was not a slow, lumbering creature. Like the rhinoceros, which also possessed pillar-like legs to support its immense bodyweight, it could run extremely fast but only over short distances. It's hard to imagine a six-ton tyrannosaurid chasing a hadrosaurid at speed for several kilometres. What's more likely is that tyrannosaurids were lurking predators waiting in ambush for their prey and catching them after a short chase.

Triceratops - the three-horned rhino beast

In spite of its overwhelming power and ferocity, T. rex didn't always get its own way. Some of its more difficult prey, like Triceratops, could inflict nasty injuries. One of the strongest dinosaurs, Tricer's massive horned skull and over 6 m (nearly 21 ft) long, barrel-like body were built to withstand attack from the fiercest predator. It could charge at more than 25 km/h (15 mph) against an attacking meat-eater.

Huge head

Tricer's enormous head made up almost one-third of its overall length. The head was armed with long, sharp horns on the brow and nose, which could be used as fearsome weapons if they didn't scare off an attacker. The head-frill was edged with bony lumps, protecting the dinosaur's powerful neck.

Crash barrier

Triceratops' thick skull and strongly built neck and hips helped it to withstand the impact of crashing into an attacker or locking horns with a rival.

Euoplocephalus - the armoured dino

Another worthy foe was Euoplocephalus ("well-armoured head") of the Ankylosauridae family, a four-legged armoured dinosaur up to 7 m (23 ft) long and weighing about 2 tons, with a broad beaked head and massive limbs. Like many other plated dinosaurs, Euoplocephalus had a leathery skin studded with bony lumps and bumps. Its other formidable weapon was a spiked bony club at the end of its raised tail.

Edmontonia - spiky armoured plant-eater

Edmontonia, of the Nodosauridae family, could also defend itself against T. rex. A large, four-legged plant-eater, 7 m (23 ft) long, it had a tough armour of bony plates and fierce spikes.

Pachycephalosaurus - "Thick-headed Lizard"

This was the largest bone-headed dinosaur: a two-legged plant-eater 4.6 m (15 ft) long with a high-domed braincase 25 cm (10 in) thick, low spiky snout and sharp knobs at the back of the head, making it look like a crash helmet.

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.

Horned defence

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 …

Moving … in a trice

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.

Master scavenger?

Some people think Tyrannosaurus may not have been so much the grand predator of the dinosaurs as the grand scavenger. Because of its leg joints and the position of its feet, the argument goes, it could only take very short steps, moving at about 5 km/h (3 mph), and therefore could hardly have chased and fought with the other animals. This, of course, contradicts the view that T. rex attacked in short fast bursts.

Meat slicer

Tyrannosaurus' 15 cm (6 in) long teeth were saw-edged and ideal for slicing up meat, but they were also very thin and could well have been broken in combat. So it is possible that T. rex may partly at least have scavenged for food, eating the bodies of dead animals which had been killed by other predators. After it had discovered a large plant-eater's carcass, T. rex squatted down beside it, ready to eat up its dinner.

Feeding time

Whether Tyrannosaurus scavenged or hunted, the prey would have been rapidly torn apart. Its jaws, armed with those large serrated teeth, would have sliced through the skin and flesh of the carcass. Violent twisting and tugging of the head, aided by T. rex's powerful neck and legs, would have torn the most powerful of sinews, so that great chunks of flesh and bone could have been swallowed whole.

Thick skull

Another theory is that, as tyrannosaurid skulls are heavily reinforced, they may have attacked their prey by running into it jaws agape, the shock of such a collision being absorbed by the skull bones.

And those tiny arms and hands?

The minute size of T. rex's forelimbs is another puzzle. One explanation is that they were used as props to help it rise from a prone position. And after a long siesta it would climb to its feet, ready for the next meal …

The demon kangaroo dino

It was quite unlike other dinosaurs, with its long upcurved skull, slender, compact proportions, sharp teeth and great sickle claws. Velociraptor was fast, smart and a highly effective hunter which was well-equipped for attack and could beat a hasty retreat from larger predators. It had large eyes on each side of its triangular-shaped head and looked a little like a kangaroo.

A ferocious little beast

The ferocious raptor had long, clawed fingers and toes, with hands that could grasp and clutch its victim. Known for its strength and speed, its size and shape were perfectly designed to capture swift, lightweight prey. Scientists know it could also handle larger animals because of its wide jaws. Its most distinguishing characteristic was the sickle-like claw on the second toe of each hind foot, just right for slashing meat. Pound for pound it was among the most powerful known predators.

Family ties: Is it a bird? No, it's a raptor

Velociraptor flourished in the Late Cretaceous period, 80 million years ago. It belonged to the family of theropods known as Dromaeosaurs. However, to confuse matters, in recent years it has also been classified as belonging to another related family - that of the feathered, winged Archaeopteryx, believed to be the direct ancestors of the first birds. Not that raptors had feathers, nor could they fly, but they share many characteristics of primitive birds. And the word raptor itself means "bird of prey".

"That doesn't look very scary - more like a six-foot turkey"

If you've seen Jurassic Park, remember the young boy whose sceptical attitude is replaced by one of terror and awe as the palaeontologist describes the pack-hunting methods of attack of the little creature on the TV monitor? Yes, that was Velociraptor.

Where's the evidence?

Remains have been found in North America, China, Mongolia and Russia.

Anyone for sickle claws?

The most dazzling feature of Velociraptor is the tremendous sickle claws, far larger than in any other known predator. They can be compared to the sabre teeth of some extinct cats, weapons of power way beyond what was normal for animals of their size. Among theropods only Tyrannosaurus, with its huge skull length, could equal velociraptor in total power relative to weight. The claws enabled them to be big-game hunters, capable of felling animals much bigger than themselves.

Velociraptor antirrhopus - fantasy beast

Found in Montana and Wyoming, V. antirrhopus is 3 m (10 ft) long with a skull length of 332 mm (13 in), femur length of 284 mm (11 in) and weighing 45 kg (86 lb) (though the largest example was 3.3 m (11 ft) long with a 45 cm (1ft 6 in) head), its long, low, streamlined skull and fantastic array of claws have turned it into an extraordinary fantasy creature - except, of course, that it existed!

V. mongoliensis - locked in combat

The most advanced species of Velociraptor, it has a greatly elongated snout. Found in Mongolia, it was 2 m (6.5) long with a skull length of 190 mm (7.5 in) and femur length of 200 mm (8 in). Amazingly, remains show it locked in combat with a small horned dinosaur, the raptor's hand still gripped in the protoceratopsid's beak!

A steering tail

A fast runner, raptor's long, stiff, slender, rudder-like tail enabled efficient steering. The tail end, marked by two bands of long, ossified rods, exerted stiff whip-action balance for hard manouevres, while the first few vertebrae behind the hips could bend 90 degrees upwards. It was thus both flexible and rigid.

A bit of a bird

Birds have unique "saddle-shaped" necks, which can be seen in Velociraptor, with its lightly built upturned skull and curved neck. So successful was raptor's design that its form hardly changed for 50 million years - a rare achievement.

Snapping jaws and slashing claws

Velociraptor had vicious jaws that would bite the flesh of its victims, sometimes while they were still alive! It could do this because its main weapon was the slashing claw on its hind foot. The jaws were secondary weapons. It killed by deeply raking the prey's limbs or belly with the sickle claws on the second toe of each hind foot, probably disembowelling the victim. Both claws were used in tandem, to double the effect.

The raptor's prey

Velociraptor was a Prehistoric "Jack the Ripper". The victims of its predatory raids of terror were generally larger plant-eating dinosaurs, like Tenontosaurus ("sinew lizard"). This bipedal/quadropedal (both two- and four-footed) beast about 21 ft (6.5 m) long, had a deep head, toothless beak, broad five-fingered hands and four-toed feet, with long arms and a strong deep tail which perhaps it swung in vain to defend itself against raptor's attack.

How raptor was discovered

The original specimens of Velociraptor were collected in the early 1920s by an American expedition to the Gobi Desert in Mongolia. It wasn't clear what kind of dinosaur it was until the discovery of Dienonychus, a similar predator, in the 1960s showed the powerful jaws and great hunting claw on the foot in detail.

Even "Plunderer" was vulnerable

In 1971 researchers made a remarkable fossil find: the skeleton of a Velociraptor that had died while attacking a horned dinosaur called Protoceratops ("first horned face"). This Late Cretaceous four-legged plant-eater was 1.8 m (6 ft) long with big head, parrotlike beak, shearing cheek teeth, broad bony neck frill, thickened bones above the eyes and snout and a bulky body.

Tit for tat - horns for claws

Apparently the predator killed its prey by disembowelling it. At the same time the Protoceratops, with its armoured head, somehow impaled the raptor. And so the two died - intertwined together.

THE RAPTORS ARRIVE

A sunny day in Montana, 80 million years BC

In the humid plains of Montana in the Lower Cretaceous period, a Tenontosaurus is grazing in a clearing, having left the safety of the trees to feed on the plants that grow on this sunny spot. It is a rash move for it has made the plant-feeder conspicuous and vulnerable to attack from predators.

The raptor appears, moving lightly like a bird, bobbing its head. By instinct, Tenontosaurus freezes, genetically programmed to believe that if it doesn't move the raptor won't be able to spot it. But unlike T. rex, whose visual acuity is based on movement and who will lose its prey if it doesn't move, Velociraptor keeps Tenontosaurus in its sights.

For long long seconds the two creatures stare at each other in silence and still without moving. And that's when the attack comes. Where Tenontosaurus is least expecting it …

Slash from the side

The attack comes not from the front, but from the side …

Tenontosaurus doesn't even see the other two raptors. Velociraptors hunt in packs, using co-ordinated attack patterns. They slash at Tenontosaurus with their six-inch retractable sickle claws, wounding its flanks and soft underbelly, using their stiff tails to balance themselves as they turn and turn again, slashing with demonic efficiency.

Tenontosaurus can bite with its beak and kick hard. It's also a fair runner, but its power is no more than that of a big horse and no match for the raptors' concerted attack. Still alive, Tenontosaurus staggers and falls as the Velociraptors start to eat it, disembowelling their victim.

And all this could actually have happened …

The main Velociraptor quarry in Montana includes pieces of a Tenontosaurus which the Velociraptors may have been feeding upon when they all died together.

The mysterious case of Archaeopteryx's wishbone

In 1861 fossil hunters came upon the bones of a perfectly preserved Late Jurassic creature in a German quarry. This reptile had died 150 million years ago. But the mud into which it fell hardened before the skeleton could be destroyed by natural decomposition or scavengers. When they inspected it closely, scientists made an extraordinary discovery: the reptile was covered with feathers!

Dinos with wings?

The tiny feathered dinosaur was 0.9 m (3 ft) long, had thin, fine-boned legs, long, delicate toes and slim jaws with short teeth. Its feathers lay along its slender arms and the long bones of its tail. It was named Archaeopteryx ("Ancient Feather") and it was soon found to share yet more characteristics with birds. Most extraordinary of all, Archaeopteryx had what was clearly a wishbone, just like those to be found in the collar bones of all birds, and which no other animals have.

But what's this to do with Velociraptor?

Well, for the next hundred years scientists debated about the link between dinosaurs and birds. The doubters argued that whereas Archaeopteryx's wishbone had clearly evolved from a collar bone, the coelurosaurs - which were the dinos that resembled Archaeopteryx most closely - didn't even have a collarbone.

But Velociraptor did!

In the 1970s palaeontologists made some startling fossil discoveries. They found that Velociraptor and some other coelurosaurs did have collarbones that could well have developed into Archaeopteryx's wishbone. Scientists now generally agree that Archaeopteryx is related to Velociraptor and some coelurosaurs, and the debate has moved on to such questions as the function of Archaeopteryx's primitive wings, why feather first evolved, how skilful they were as fliers and where they lived.

Little Compy - the miniature dino

Compsognathus is one of the smallest dinosaurs ever found, being roughly the size of a guinea hen. With its long legs and tail, it was able to run extremely fast.

Not so much a cannibal, more of a lizard-eater

The Compsognathus resembled a wingless bird, with its narrow jaws and sharp teeth. These razor-sharp teeth show that it may have eaten small vertebrates as well as insects. One well-preserved skeleton was found with a lizard in its stomach. With its long neck and flexible forearms, Compsognathus was a light, fast predator. The little Compy had a small head, low skull and massive upper leg bones. Its feet were birdlike with three-fingered claws. It had a long, whiplike tail and a long, narrow mouth. Its eyes were positioned back along the sides of its head. Compy proved to be an agile, crafty hunter.

One of the smallest of the small

Compsognathus longpipes (meaning "Pretty Jaw" or "Elegant Jaw") was a small theropod, one of a diverse group of lightweight, predatory saurischian (lizard-hipped) dinosaurs that were widespread from Late Triassic to Late Cretaceous times (231-65 million years ago). Compy was one of the smallest, at about 70 cm (28 in) long, but even the largest small theropod, Coelophysis, was only 3 m (10 ft) long.

The perfect specimen

Closely related to Coelurus, it lived at about the same time. Only three specimens of Compsognathus have been found - in south-east France and Bavaria. A single complete skeleton was found in Germany in 1861, pressed in lithographic limestone. A fascinating fact is that this was one of the most completely preserved sets of dinosaur bones ever found.

Airhead

Compy had a light, sharp-snouted skull. Large open spaces allowed its muscles to move. The eye sockets were large and this dinosaur probably had large eyes to help it find and chase its prey.

Not just another turkey

One of the smallest-known dinosaurs, Compsognathus longipes was about the size of a turkey, measuring only 70-140 cm (28-54 in) in length and weighing 3 kg (6.5 lbs); its average skull length was 76 mm (3 in); femur length 67 mm (2.6 in); and hip height 0.21 m (8.3 in) .

Sharp teeth

Such a small, agile hunter needed sharp teeth to deal with its prey when caught. Compy had about 68 small, widely spaced, delicately curved teeth in its jaws. The front teeth were more conical than those behind and lacked serrations. The front lower teeth radiated from one another like the spokes of a wheel. All this indicated that this house-cat-sized theropod was a full-time small-game hunter; the semiconical teeth couldn't do much damage to a big victim. This isn't surprising since its home was a Jurassic European group of small semi-arid islands upon which only small vertebrates (like lizards) lived.

Where did Compy live?

Compy probably lived on the unforested shores of lakes and lagoons - its footprints have been found in sand and mud. This was a popular place to live because there was plenty of water and vegetation, and sandy soil in which to lay their eggs. Compy may also have eaten scraps from the water. It was alert with good senses and it needed them in a world full of bigger dinosaurs.

Short lifespan

Compy had large eyes to look out for and chase prey, and to watch out for enemies. Its speed was useful for avoiding predators. Despite this, it probably had a short lifespan, and may have laid large clutches of eggs to ensure the survival of its species.

Prehistoric heating shortage

If dinosaurs were warm-blooded, it is the small animals like Compy that would have had difficulty finding enough food to keep warm - the bigger dinosaurs seemed to fare much better!

The riddle of Compy's "death throe"

The single skeleton of Compsognathus longipes found in 1861 was the first complete dinosaur skeleton ever discovered. The skeleton is twisted backwards and some pieces have been moved apart. The tail's lifted up; the head bent back over the tail. This was considered an unnatural position, indicating that Compy was in agony.

Did it die in its sleep?

In fact, when long-necked animals die, their neck muscles and ligaments dry and shrink, causing the neck to curl backwards. Gases from rotting part of the flesh of other parts of the body may cause bones to move apart. Nearly all the bones have been preserved, but almost half the tail's missing. Although Compy's head has been turned upside down, the bones around the brain have been fossilized. The back legs are still in place on both sides of the pelvis, and the tiny, sharp toe bones have hardly changed.

More about that skeleton

Compy's skeleton, like that of Coelophysis and Ornitholestes (both coelurusaurs), was lightly built: these animals were comparatively small for dinosaurs and presumably did not have serious weight-bearing problems. Its neck was long, flexible and joined onto a compact body. The animal was bipedal (two-legged) with strong, slender back legs and reduced, but still useful, front legs. Compy's fingers were armed with strong claws for grasping prey. Its tail was long, acting as a counterbalance for the front of the body.

Windows in the skull

Compy's skull contained open spaces - windows. These had two functions: they lightened the skull which aided Compy's speed and mobility and they left extra room for the muscles which opened and closed its jaws. These windows were: (a) nasal opening; (b) antorbital opening; (c) orbit (for the eye); (d) upper temporal opening; (e) lower temporal opening; (f) mandibular opening. In the armoured skulls of such dinosaurs as Panoplosaurus these holes were closed.

A diet of reptiles

The specimen of Compsognathus discovered in 1861, like of those of Coelophysis, had small bones inside it, and it was thought that Compsognathus was also a cannibal. It has now been shown that the bones belonged to a lizard, Bavarisaurus.

Looking for lizards

A two-legged runner, Compsognathus caught fast-moving insects and small lizards. Its long back legs and long four-toed feet were essential for providing the speed it needed.

A glimpse at Compy's life

Time: 155 million years, BC

Place: island in the Upper Jurassic lagoons of Germany

In lush undergrowth among tree-like cycads and stubby palmlike cycadeoids, with gingkoes, ferns and tree ferns clothing river banks in forest, two Compsognathus run through horsetail thickets, chasing sphenodontid lizards and dragonflies. Above them pterosaurs dart through the air, catching prey. An Archaeopteryx, the first bird and Compy's close relative, squawks a descant over the buzzing symphony of insect and reptile sounds.

Why only two fingers?

Compy had only two complete fingers on each hand. The third finger was only one bone.

Scientists are stumped

Small arms like those found on Compy were not used for walking or running. The two short-fingered hands may not have been much use for grasping prey either. Scientists still do not know what Compy did with its hands.

Who are Compy's descendants?

It is difficult to compare Compy with any living animals. There are very few two-legged carnivores about - all the two-legged ones are birds (like kestrels and eagles). But they are not that similar to Compy. After all, Compy was a ground-living dinosaur (it couldn't fly!) and had scaly skin, not feathers.

Dinos, birds and crocs

Although about 64 million years ago dinosaurs became extinct, there are animals today that bear some relation to them. Two surviving relatives of dinosaurs are birds and crocodiles.

Ancient ostrich … without feathers?

It is believed that birds emerged from a common ancestor during the Jurassic period, about 190-300 million years ago. But it is more likely that birds evolved from two-legged dinosaurs, like Compy, which could have been the ancestor of the ostrich, looking very similar apart from its scaly skin, long tail and arms.

Ancient case of mistaken identity

The first recorded skeleton of a feathered dinosaur - Archaeopteryx - was incredibly similar to Compy. Its bones have even been mistaken for Compsognathus' fossils. They did differ - their hips varied and Arch had longer legs to support its wings. Arch probably ran like Compy with short bursts of flight to catch insects.

What made dinos fly?

It's easy to understand why dinosaurs took to the air - it meant that they would have been safe from predators and enabled them to travel long distances with ease in their quest for food.

Separated at birth … or just good friends?

For fast-moving dinosaurs like Compy, it was logical they would eventually want to take off into the air. Compy's limb bones resemble those of birds - the forelimbs with 3 digits and hind limbs with 4 toes. Dinosaur ankles are also like those of a bird, with heel bones fused to the shin bones. Dinosaurs also had a skull with more holes in it than other reptiles - two openings behind the eyes and one between the nose and mouth. Birds have a version of this skull today. Dinos also show the existence of blood vessels and air-sacs in their bones, just like birds.

Compy lives!

Next time you see a bird, imagine it with scales instead of feathers, and arms and claws instead of wings. And a long tail. Then increase its size massively and there you have it - your very own Compsognathus in your back garden!

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 rocks.

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

Moulds: certain minerals dissolved some bones but left bone-shaped hollow fossils called moulds

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 (fast runners' footprints would be far apart), and travelled singly or in herds

Coprolites: these fossil droppings are moulds showing the shape of the intestines

Ooliths: fossil eggs

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 19^th century, when dinosaurs had just been discovered, the sculptor Benjamin Waterhouse Hawkins built models of dinosaurs first in Britain, then in America.

Europe

Dinosaur remains have been found all over Europe, but the fossilized skeletons tend to be less complete than elsewhere (with the notable exception of Comfy). The word "dinosaur" was first coined in England in 1841 to describe the three known giant reptiles at the time: Iguanodon ("Iguana Tooth"), a plant-eater found in great numbers; Megalosaurus ("Great Lizard"), a large heavily-built two-legged predator 9 m (30 ft) long and weighing a ton; and Hylaeosaurus ("Woodland Lizard"), a four-legged armoured plant-eater.

North America

This part of the world has been popular with dinosaur hunters since the mid-19^th century. Famous finds include: Tyrannosaurus, Diplodocus ("Double Beam"), a long four-legged plant-eater; and Stegosaurus ("Roof Lizard"), the largest known plated dinosaur, a four-legged plant-eater 9 m (30 ft) long. New dinosaur remains are still being discovered here.

South America

Important finds include the two-legged flesh-eater Herrerasaurus, one of the earliest known dinosaurs, who lived 230 million years ago.

Africa

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 the finds are: Spinosaurus ("Thorn Lizard"), an immense two-legged predator with huge teeth and vast crocodile-like lower jaw.

Asia

Some of the most recent and exciting finds have been made in Asia, including Tarbosaurus ("Alarming Lizard"), a two-legged flesh-eater whose immense head contains huge jaws armed with terrifying fangs. 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.

Australia

Not many dino fossils have been found: the most complete dinosaur discovered here.was the plant-eating Muttaburrasaurus.

Antarctica

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.

Extinct theories …

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 animals.

… 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.