They walked on two legs, laid their eggs in nests, and some even glided through the air – find out more about the theropod dinosaurs, from which all birds evolved.
- Birds are vertebrates and have lightweight bones.
- Birds are warm-blooded.
- All birds, including flightless birds, have wings.
- All birds reproduce by laying eggs.
Despite their diversity, all birds evolved from the same set of ancestors - a group of dinosaurs called the theropods.
Theropods ranged enormously in size from the huge spinosaurus – up to 13 metres in length – to much smaller dinosaurs, like the three-metre-long saurornithoides but they did share some similarities. ...
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