What Preyed On The Phenacodus

What else might have happened?

A No one can be sure that an asteroid collision alone was the cause of the dinosaurs' extinction. Scientists also think that at the end of the Cretaceous Period there were numerous volcanic eruptions in India. These might have polluted the atmosphere with so much dust that the Sun's rays could not penetrate, and many creatures may have died of cold.

Erupting volcano

Tyrannosaurus rex

Tyrannosaurus rex

Pterodactylus

Did flying reptiles all die?

| A Throughout the time of the dinosaurs, the skies were filled with flying reptiles, but no pterosaurs survived the mass extinction. Reptiles would never take to the skies again and no human would see a Pterodactylus or a Quetzalcoatlus, the largest flying animal ever, swooping overhead.

Quetzalcoatlus

What happend to marine animals?

| A When seas still teemed with life, the most dominant groups of sea creatures were the dinosaurs' distant relatives, marine reptiles. Like the dinosaurs, the marine reptiles, such as Mosasaurus, were all killed in the extinction event. Many other sea creatures died out or were seriously diminished, although fish were mostly unaffected.

More Facts

■ One early theory suggested that the dinosaurs' extinction was caused by mammals eating all their eggs.

Which meat-eaters were the last survivors?

A The big theropod T. rex was among the last meat-eating dinosaurs to walk the Earth. After the asteroid impact, dead and dying animals would have been plentiful, so it is unlikely T. rex died of hunger. It is possible that, together with other dinosaurs, T. rex died out because the low temperatures made all

Which plant-eaters survived to the end?

A The ankylosaurs were some

Ankylosaurus

of the last herbivorous dinosaurs. It is possible that smaller plant-eaters close to the spot where the asteroid hit escaped harm by burrowing into the ground. In the long term, these plant-eaters would have gone hungry because many plants were damaged or destroyed by the lack of light and heat.

Ankylosaurus

The First Dinosaurs And Mammals

Who was top predator after T. rex?

It was millions of years before big animals reappeared following the mass extinction. While the dinosaurs were alive, mammals remained relatively small, but they gradually evolved to replace dinosaurs as the dominant land animals. Hoofed beast Andrewsarchus became the biggest carnivorous land mammal ever. However, these large mammals faced competition from an unlikely source when birds also evolved into fierce predators.

What did predatory mammals eat?

| A Andrewsarchus would have been able to hunt down plant-eating mammals, resembling this early hoofed herbivore called Phenacodus. About the size of a sheep, Phenacodus was lightly built so it stood some chance of escaping a predator. It probably lived in herds and kept to forests for feeding and shelter.

Phenacodus

Heavy body covered i dense fur

Phenacodus

Phenacodus

Heavy body covered i dense fur

Uintatherium Predators

Huge canine teeth for crunching through bone

Toes tipped with short hooves

Huge canine teeth for crunching through bone

Toes tipped with short hooves

Uintatherium

When did big plant-eaters reappear?

| A Some 20 million years after the mass extinction, big plant-eating animals were back on the scene. Uintatherium was about the size and shape of a rhinoceros and had pillarlike, weight-bearing legs. It had three pairs of horns on its head and tusklike canine teeth, which it probably used for fighting. Uintatherium lived on a diet of leaves and fruit.

Uintatherium

Enitatherium

When did bats first appear?

| A Ten million years after the disappearance of the pterosaurs, the first flying mammals appeared. Bats have changed little since then and are still the only flying mammals. Many bats are nocturnal and use their special sense of hearing to find their way and locate prey in the dark.

Large ears for hearing high-frequency sounds

Large ears for hearing high-frequency sounds

Uintatherium

Did early mammals live in water?

| A This animal looks like an otter, but was, in fact, a very early whale. Although Ambulocetus could walk on dry land, it was also a powerful swimmer, showing how whales evolved from land-dwelling mammals. It would take about 10 million years before watery mammals such as Ambulocetus, evolved into the whales that we recognize today.

I q Which birds were predators?

| A Large, carnivorous, flightless birds became some of the world's fiercest predators. Titanis, or "terror bird," was about 7 ft (2 m) tall and had a sharp, hooked beak and huge claws. Titanis hunted small mammals on North America's open plains, where it competed with the big carnivorous mammals to be top predator.

Crocodile

Which animals are as old as dinosaurs?

Even though dinosaurs were around for 160 million years, other animals have survived for as long, or even longer. Ancient animals live everywhere—on land, in the sky, and in the seas and rivers. Many of them have changed little from their prehistoric forms— crocodilians have not needed to adapt since Cretaceous times. If their habitats are preserved, these animals could continue living for millions more years.

Did any land reptiles survive the extinction?

A Small lizards lived throughout the Mesozoic Era, and they are still with us today. Paleontologists are not sure why these reptiles were unaffected by whatever killed the dinosaurs. It is possible that when many plants had died lizards burrowed into the ground and hibernated to escape the hazardous surface conditions.

Heavily armored skin

Which are the most successful animals?

| A Insects are the most numerous and diverse animals that have ever existed on Earth. There are millions of different insect species and some of them have existed, relatively unchanged, since before the time of the dinosaurs. The oldest dragonfly fossil ever found is about 320 million years old, and dragonflies are still a common sight today.

Heavily armored skin

Feet designed for running on land

What is a crocodilian?

This is the name for a group of archosaurs made up of crocodiles and their relatives. The first crocodilians appeared about the same time as the dinosaurs and lived on land. Soon, they evolved to live in seas and rivers. Today, there are 23 crocodilian species.

I A Fossil evidence suggests that arachnids—the animal group that includes spiders and scorpions—are more than 400 million years old. There are hundreds of thousands of species today. All of them are predators, killing by injecting deadly chemicals, called venom, into their prey. The venom of some scorpions can kill humans.

Tough shell protects soft body parts

Are cockroaches indestructible?

Cockroaches could be the most hardy of all insects. They eat almost anything, but they can also survive without food for about a month. They can even recover after being frozen. Cockroaches live everywhere except the polar regions. They have existed for 300 million years.

Great white shark

What is a crocodilian?

This is the name for a group of archosaurs made up of crocodiles and their relatives. The first crocodilians appeared about the same time as the dinosaurs and lived on land. Soon, they evolved to live in seas and rivers. Today, there are 23 crocodilian species.

Which are the oldest sea creatures?

| A Marine invertebrates (animals without backbones), including clams and jellyfish, are the oldest. However, the most ancient big sea animal is undoubtedly the shark. These formidable fish have survived more than 400 million years of history, including the Cretaceous extinction.

IGeosaurus was an aquatic crocodilian of the Jurassic Period. Instead of the heavy armor that most crocodilians have, Geosaurus had smooth skin, making it a more agile swimmer than its relatives.

Geosaurus

Great white shark

Geosaurus

2 At about 50 ft (15 m) in length, Deinosuchus was one of the biggest crocodilians. Its powerful jaws could probably crush a large dinosaur.

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  • assunta
    What caused the extinction of the phenacodus?
    9 years ago
  • william
    What preyed on the phenacodus?
    3 years ago
  • Sampsa Hassi
    Where did the phenacodus live?
    2 years ago
  • Rita Samuel
    When did phenacodus live on earth?
    1 year ago

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