Two Moschops about to fight on a sandstone mesa


The therapsids include all mammals plus the many mammal-like reptiles, such as Dicynodon and the sabre-toothed gorgonopsids. The therapsids rose to prominence in the Permian to become the most successful land animals of their day. The secret of their success was in their teeth, as therapsids evolved new and better methods of chewing plant and animal food. However, the group took a hammering in the mass extinction at the end of the Permian, and was sidelined for millions of years as the dinosaurs diversified. The therapsids' ultimate successors - mammals - now rule the Earth courtesy of those efficient therapsid teeth and jaws.

Scientific name: Therapsida

Rank: Order

Common names:

beast arch

Watch video clips from past programmes (1 clip)

In order to see this content you need to have an up-to-date version of Flash installed and Javascript turned on.

Explore this group


Discover what these behaviours are and how different plants and animals use them.

Adapted to running Adapted to running
Running and walking evolved as a method of getting around when life emerged from water on to dry land. Animals that travel about on foot usually have a particular speed of gait which is their most energy efficient.

Additional data source: Animal Diversity Web

When they lived

Discover the other animals and plants that lived during the following geological time periods.

Fossil types

Learn more about the other animals and plants that also form these fossils.

Trace fossils Trace fossils
It's not only the actual bodily remains of dead animals and plants that can become fossils. Things created or left behind by animals can also fossilise, such as their footprints, burrows and dung.