Cretaceous Animals - Kids Facts

Did you know there were a lot of Cretaceous animals? Not just the Dinosaurs! Find out who else was living during this amazing time.

Animals of the Cretaceous Period

144 to 165 million years ago the earth began to have seasons, which meant colder winters and warmer summers. This caused the appearance of many new groups of mammals and birds, as well as new Cretaceous plants.

The Cretaceous was teeming with life. Some of these animals are still around today.


Creataceous Animals - Mammals

There were several mammals around during the Cretaceous. Some examples are

  • Yanoconodon
    Yanoconodon lived in what is now China. Some of them, such as Repenomamus grew so large they could eat small dinosaurs.
  • Gobiconodon
    This was a carnivorous mammal that looked like a large opossum. It grew to about 18 inches long.
  • Eomaia
    Eomaia means 'dawn mother' and was a very small mammal - about 4 inches in length. It lived in what is now China and was covered in fur.
  • Crusafontia
    A small mammal that may have looked like a squirrel.
  • Reptiles

    Dinosaurs were reptiles - but not all reptiles are dinosaurs! Here are some other reptiles that lived at this time.

  • Champsosaurus
    The name Champsosaurus means 'crocodile lizard'. It hunted in rivers and swamps, catching fish in its long tooth-lined jaws.
  • Snakes
    Snakes are thought to have evolved from either burrowing or aquatic lizards during the Cretaceous period.
  • Crocodiles
    Crocodiles have not changed very much for 200 million years. They are the largest air-breathing animals to survive at the end of the Cretacious. It is believed they suvived because they can live as scavengers and can survive without food for months.
  • Giant Tortoises
    Giant Tortoises belong to the most ancient group of reptiles. They are one of the world's longest-living animals, living for 100 years or more.
  • Flying Reptiles

    The air of the Cretaceous period was filled with flying reptiles called pterosaurs (which means "winged lizard").

    Pterosaurs are the earliest vertebrates known to have flown. They came in many sizes - from the very small Nemicolopterus to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx.

    The Pterosaurs would have preyed on the other smaller cretaceous animals and dinosaurs.


    During this era, insects began to diversify, and the oldest known ants, termites and some lepidopterans (like butterflies and moths) appeared. Aphids, grasshoppers, and gall wasps also developed. The new flowering plants of the time also brought the appearance of bees.

    Aquatic Animals

    The seas of the Cretaceous were full of fish and molluscs. This provided lots of food for predators like swimming dinosaurs. Here are some sea animals of the time :

  • Mosasaurus
    The Mosasaurus was an aquatic lizard, like a flippered crocodile. Its name means "Meuse lizard", because it was found near the Meuse River.
  • Trinacromerum
    Looking like a 'four-flippered penguin, Trinacromerum could swim very fast. It fed on small fish, and grew to about 3 meters (10 feet) long.
  • Clidastes
    Clidastes was an agile and fast swimmer. It hunted on the surface or in shallow waters for fish, flying reptiles and anything that got too close. It grew to 2-4 meters (7-12 feet) in length.
  • You can see there were lots of Cretaceous animals.

    Check out the Cretaceous dinosaurs they lived with. 

    Cretaceous Animals
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